It's great to have such an in-depth teardown of a total station, thanks Mike! The little widget on the top of the telescope is for the person operating the TS to get roughly in the right direction to point at the person with the staff - sight down the widget with both eyes open so the circle is full, and make coarse adjustments of the scope until the circle covers the top of the staff, then look through the scope and use the fine adjustment knobs to zero the crosshairs on the reflector. Normally the rodman's job is to hold the staff upright and in place and wait for the surveyor to shout that they've taken a reading. They need to keep an eye on the spirit level on the rod, and so won't be able to sight back to the TS. With staking-out (positioning the staff on a pre-computed point) the surveyor will set a known location and the TS will guide them up/down/left/right/back/forward, and they shout to the rodman to move until the reflector is in the right place. So in both cases the rodman's job is the more important - they need to choose the right location and keep as still as possible. The surveyor just needs one working eye, and the ability to press a few buttons. The black and white part of the rotary encoder is for taking double-face shots. The surveyor will sight normally and take a reading, then they will flip the telescope and rotate the TS 180 degrees and take a second reading, the TS then averages the angles which eliminates any mechanical offset errors. The ASCII chart is fascinating! The only thing I can think of is after looking at the control panel it only has numbers on it, so typing text requires the user to type in ASCII integers! That's batshit for '97! My TS is only a few years younger, and it has a speccy keyboard style alpha numeric keypad. While there's not a ton of text that needs typing - most of it can be set up in the office through the serial cable - there's enough to warrant a proper alpha keyboard.
We had a total station from about the same era at a job I worked on a few years ago. The reason the front-panel/user-interface is removable is because it was effectively the storage disk for any measurements you took. The idea was you would detach it, carry it into the office, and plug it into a desktop PC which ran some accompanying software. These things are extremely sensitive to level. The power-on process for the one we had involved it requiring you to do an extremely fine levelling procedure. You'd need to level the tripod using it's built-in level, and then that would get the overall level close enough for the internal sensor to work. I spent some time writing software to get measurements from it. It had a ridiculously terrible serial interface, which would periodically lock-up and become unresponsive.
My Nikon TS from the late 90s/early 00s is also a painful device to use. It doesn't have a detachable keypad, so you have to lug the whole thing to the computer to do any comms. Thankfully I've not had any crashes with it, but it is still a faff to get what you want and then translate the output to something less ~batshit~ memory efficient.
I was once given a Spectra Physics “Dial Grade” pipe alignment laser, as a teenager. A fascinating unit. Way, way before the internet I would work my way through the “Yellow pages” asking for old or discarded equipment (that’s how I got my first ever job at 16, as a TV & VCR apprentice). I sat up all night and took the “Dial Grade” apart on the sitting room carpet. I was new to taking things apart back then in the 90s; it was all so magical and exciting. I didn’t have a torx driver (they were mysterious, exotic things) and so persisted in forcing the security screws undone with ingenuity and brute force. I still CLEARLY remember the beautiful iridescent shimmer of the thick red HeNe laser beam, and the prettiness of the light reflecting off the coated lenses and dichroic glass prisms. I would clip the leads to a car battery next to my bed and shine it out across the fields so it hit the wooded area about a mile away. Beautiful memories.
If the beam looked irridescent, that HeNe was an impressive HeNe indeed! Colors other than red are rare, especially as power increases and the higher gain lines start to dominate.
"The ASCII table can be used to enter alpha characters directly from the keyboard on instruments with a numerical keyboard. This can be done with the help of the (ASCII) key.", from "Pentax total station operating manual". Cheers !
For the ASCII table - I've also seen them on old mobile road signs. The interface for entering the message is just a 3x4 keypad, so you enter ASCII directly. I assume people using this would also use those road signs.
Thank you for the tear down. Reduces my urge to tear mine apart. With careful battery change I think I can get some years of life out of mine when I learn to use it. The User interface on these units is abysmal with cryptic numeric command codes that made sense when the first total station was made and then the surveyors learnt the codes and did not want anything to change. I'm reasonably sure that this was originally the Geodimeter brand that was purchased by Spectra Precision and then by Trimble. The earlier units had a DE-9 connector and later a 4 pin so this case was perhaps made during the change over period. The DE-9 connector has RS-232 or ASYNC TTL and power on non standard pins but not sure what the other contacts on the 6 way slip ring were for. I have a GDM424 Geodimeter unit that is before this one and this was probably one of the 500 or 600 series units, I think some model numbers were changed somewhat when the ownership changed (Trimble may have added 5000 to the model number). The displays came in numeric and alphanumeric versions (cost cutting a keypad) so the ASCII table was to enable a numeric interface to easier enter alphanumeric names for the surveyed points. The various units had either just calibration constants stored in the units with the battery backed ram or some of the 500, 4000 or 600 series units had the user interface program also RAM backed up. Earlier than the 400 units some had the fixed constants loaded into RAM memory as well that were the same for all units, perhaps they thought that some error in hardware or software could be compensated later by adjusting the speed of light to air density calibration. In the end all of these earlier units become doorstops if they loose their battery data because Trimble can no longer access the factory presets and except for one enthusiastic fellow nobody has any way to generate the calibration constants for the units. This amateur specialist might be happy to get copies of the ROMs for his collection. The little telescopes are for coarse sighting for the operator. Some devices have a light beam they shine to the pole holder so he can point the prism (reflector) at the operator at the ranging station. Some of the units with motorised sighting had detachable keyboards with radio link provisions, later units this was standard. The lone button was to take a reading when the unit was flipped over and the keypad was on the other side. Not much used on these because the factory calibration and the internal levelling (compensator) provided almost the full accuracy with just a single sighting. Some units could send voice signals to the pole holder via the measuring beam to an optical receiver attached to the pole with the prism. I found a table that indicated some of the modulation frequencies used to calculate the ranging and while I did not follow why they were chosen it seems that there is some important reason. Here is a selection of the frequecies in Hz. 29970000 14985530 14985543 14984651 14984629 14985453 14987103 14987090 14983482 14985400 These were from 4 manufacturers including some Geodimeter but not these particular units where cryptic notes hints at the reason. Note (i) The carrier wavelength can vary between 850nm and 910nm due to the use of different types of diodes from various sources Note(j) The manufacturer selects the modulation frequency (~15 MHz) according to the actual carrier wavelength (as well as the 10M unit length) so that the same C and D terms can be used for all instruments The "Terms of first velocity correction" indicated as C=275 and D=79.55 are the same for all but the very early Geodimeter total stations. Other vendors have different constants. Geodimeter also has their "Reference Refractive index" = 1.00275 for later units, other vendors have different values. "?" gives a command list on some units. Someone called mike1202 offered the following serial commands, "OV*" - dump memory, "RV,100" - GDM model "RV,110" - loader time and date "RV,111"- GDM serial number "RV,113" - program version Some others can clear all RAM memory The open source project is on GITHUB user ROBOTS project GDM I think that may be the same user that provided the command list above.
The empty space behind the one side panel is for an optional extra battery compartment or an optional radio link. The hole in the battery compartment where the logo is visible is where the TrackLight would shine for the "rod man" to know where the operator is standing so he can orient the prism appropriately. The TracklLight is cool because it changes colour like glide slope indicators at a runway. The station operator can point to where he wants a measurement to be made and then the rod man can move along a line to the point where the light changes colour from red or green on the sides to white in the middle. The 600 series came out in 1994 with the models 610, 620 and 640 You can see a lot of history in a document. Search for "The History of Geodimeter J.R. Smith"
Hi Mike. Thanks for another really interesting vid. you always get some rarely available stuff and show us curious folks a really good look around inside and out.. from menial to mega complex, with good descriptions to help us understand what we are seeing. Love this channel. Thanks Mike. :)
I worked at Tripod Data Systems (now Trimble) and we sold quite a few of these, although they were branded as Nikon. I never got to take any apart though!
regarding the strange positions of the pins in that photodiode package, it looks like that puts one pin in the center of the package, so I would guess the actual photodiode die is mounted to the face of that pin. That would provide some improvement in package parasitics versus the other method of mounting the die to a shelf in the can base and bonding it out to the pins. The latter method is more common in laser diodes for better thermal coupling of the die to the can, but means the diode is either electrically bonded to the can or is capacitively coupled to the can via an insulating layer. Putting the die on the face of a central pin isolates the diode entirely from the can without the capacitive coupling and eliminates one set of bond wires.
The only reason I can think of for the ASCII table is that on average, it is likely faster to type in the B10 ASCII codes than it would be to type it in flip-phone texting style. The learning curve would be a lot higher though.
The 'load' bearing on the foot probably isn't there for taking load, as the other bearing would be more than enough to do so. It's my guess it's for better precision by taking out any possible wobble from the other bearing.
Very nice I've always wanted to see a total station tear-down. I've only read about inductosyn encoders, never seen one dismantled. For getting down to 1 second of arc it has an impressive lack of poles, so most of the resolution is from phase measurement. Yes I suspect the coarse optical is for absolute ambiguity removal. I wonder if they calibrate the encoder to remove its stationary non-idealities rather than relying on precision construction and alignment?
The ASCII table is likely useful because they didn't have the option to press a number several times to get 'abc', 'def' etc, like on a 90'es cellphone (before T9 dictionaries). Even though the date codes say 1997 the design is likely much older
I worked at an engineering company that used total stations. It's high precision stuff because they would use such a device in multiple steps into a long tunnel to get the "GPS" coordinate of the end so if you want to have mm precision 1km down you need precise angles. I wonder if the encoder could be done with a passive rotor with a tab that changes a wave guide length and use RF and phase detection. That way you have a single location for electronics and presumably inexpensive. time of flight should be fairly reliable, maybe air density compensation. With clever arrangement a single emitter might be able to determine the angles of multiple encoders. That would be kind of neat.
It's called total station becauae it makes angular and distance measurements, error calculations and mapping calculations all within this single instrument in contrast with traditional geodesy methods.
I've wanted a basic digital theodolite (don't really need GPS, but a rangefinder would be nice) for ages... despite not actually having a dire need for one. :) They can be quite handy, even indoors in a machine shop!
The hand held laser range finders that you can get for EUR30 at the hardware store are remarkably convenient though limited in range and probably accurate to about 10mm. With used total stations you get a little more accuracy and the angle readings but the old units are a gamble if they break or have lost their RAM battery voltage. Some units loose constants, calibration or even firmware.
When Mike mentioned inductive sensing via a transformer, the first thing I thought of was a resolver. I have an old CNC that uses those for position feedback.
It looks like a theodolite that we use to align precision aircraft optics . Digital data is sent to an external computer to calculate/display pass/fail criteria. The device we use was sourced from a major UK company.
Welcome in the very private club of youtubers who teardown total stations 😂 The name of total station might be because it does the job of a theodolite + the job of a telemeter + the computations, so basically the work of formerly several different devices.
Yes I was thinking the same, but wonder if it started with one manufacturer's product and then became a general term, like Hoover for vacuum cleaner ( in the UK at least) . Great channel BTW.
...Looks like an older vintage Geodimeter 600 rebranded-purchased under Spectra, Trimble names, A Trimble 5600 with out radio-remote servo's, late 90's unit... Front control panel plate is easy to find on-line.
Seeing the split lens reminded me of an old non electronic theodolite i was shown, iirc, when the theodolite is perfecty horizontal, a line in each side lines up with each other.
You’ve got it backwards. Those little sights aren’t for the guy holding the prism. They’re for quick rough sighting by the instrument man. Look at them from the eyepiece end and you’ll see an arrow that you can then line up with the target.
pretty sure that if object is in the middle on all axii, the accuracy end is where ever you point it. not which side you look through. if you look thru the wrong end and still get it all lined up, thats jedi master level skills territory 😂🤣
@@Palmit_ it’s a lens assembly, it not just a tube with a mask in the middle. I have them on a couple total stations and theodolites. When viewed from the eyepiece end, the arrow can be seen very clearly.
Hey ! Good day to you ! I was wondering if you can and want to do some video about that new "Sphere" in Las Vegas, if is so good as they say and what is needed to power it and manage all that amount of data. Cheers !
I reckon comms issues are probably some strange protocol used in the device; For it's application it's nothing to be expected, back in the day EE's just used whatever they liked that met the project specs.... I laugh because I like how Mike always tries to follow a logical layout within his own designs and something worth taking on board in electronics design.
On the image with the user interface i noticed it basically only has numbers. Maybe it was to enter text because they didn't bother implementing a complicated UI for it.
If you google image Precision Constructor Total Station you can see the detachable keypad/memory device and it only has a number pad + a few extra keys
Hey Mike, just wanted to ask if your going to be at Gaussfest this year? I've been watching your channel for 12 years now and it would be cool to meet you mate, thanks in advance Steve... 👍👍
مرحبا سيد ستيف لاحظت انك ذو خبرة كبيرة أود أن أسألك عندي جهاز تريمبل5600 قديم بدون راديو موديل عام 2001 اريدطريقة قياس مسافة او زاوية هل تستطيع مساعدتي
Optical encoders often have an index mark but they usually don't give you an absolute position "cold". You have to pass the index point and then count ticks from there. Versus a magnetic device that gives you sin/cos outputs that you can always get the abs position from. This appears to be neither, however.
@@rfmerrill Yes with an optical encoder on power on you would have to rotate the head through the index mark. Have used an absolute optical encoder but they are very complex and expensive for high resolution. This looks like a large PCB based RVDT. Or it just might just be PFM
Sure, quadrature optical encoders aren't usually used for absolute positioning since you would need to have some sort of indexing, but Gray code encoders will give absolute position right off.
*Summary* *Introduction and Basic Features of Geodometer* 0:00 - Introduction to a geodometer, also known as a total station 0:16 - The device is used for surveying buildings, roads, etc. 0:23 - The geodometer maps out positions of objects in 2D and 3D space 0:33 - Features include a laser range line and a telescope 0:52 - The device maps out an area by measuring angular positions and distance to an object 0:59 - Initially assumed this would be a remotely operated model 1:37 - The model appears to be a standard manual one without the user interface or computer panel 1:53 - Expectation is for high precision angular measurement and laser rangefinder 1:56 - The geodometer is a Spectra Precision Constructor 2:13 - Differences between different brands would likely be in precision 2:23 - The ASCII code table on the front of the device is puzzling *Physical Features of the Device* 2:52 - Bottom part of the device is the battery 3:00 - The battery also serves as counterbalance 3:12 - There are various knobs on the side and the bottom of the device 3:16 - The device features a telescope with a focus adjustment 3:26 - Telescope is of high-quality and long-range zoom 3:34 - There is a button on the front of the device 3:38 - Alignment aids on top and bottom help the person at a distance to line up with the lens 4:28 - The device features a 4-pin connector possibly for power and RS232 4:38 - There is a connector for a user interface or a computer that does calculations based on the angles and distances 4:44 - The device features an interconnect board and a push button on the front 4:46 - The side panel features an encoder, an 80c32 processor, external prom, and some RAM 6:03 - Inductive coils and opto reflective sensors provide high resolution output for angle measurement 7:14 - The encoder is connected directly to the rotating sensor 7:45 - The encoder provides both absolute position reference and a high-precision output *Further Investigation and Component Details* 9:29 - There is a PCB inside the cover with a couple of backup batteries 9:38 - The device features two knobs for adjusting each axis 10:01 - The device features a Sounder. (10:04 - 21:20: Details about components identified and their functionalities are discussed) - 10:04 Discussed a hearing aid type called Sounder - 10:08 Spotted a unique object - 10:11 Noticed several components including a 87c51 single chip micro, ram ewart chip, rs232 drivers, and analog switching - 10:29 Noticed power supply components and batteries - 10:31 Suggested batteries could be backing up the Ram and discussed user interface - 10:37 Noticed an inductor, believed to be associated with the power supply - 10:41 Discussed knobs and their functions - 10:47 Explained the process of course and fine adjustments using the knobs - 11:09 Suggested it is a way of providing course adjustments - 11:19 Noted similar functions for the rotation axis - 11:24 Introduced a locking mechanism - 11:41 Identified a similar type of encoder seen on the vertical axis - 11:47 Noticed a sensor connection, believed to be used to generate the field for the Central rotor - 11:57 Suspected the connector may be part of a slip Ring Time arrangement - 12:03 Saw a fuse which is likely for the power connection - 12:13 Suggested different versions may exist based on outdoor usage - 12:25 Noticed a slip ring assembly at the bottom - 12:34 Discussed the load bearing system - 12:39 Noted heavy plated copper for the slip rings on the PCB - 12:47 Noted duplicate tracks and contacts for redundancy - 13:05 Suspected a module to be a level sensor - 13:16 Predicted a ball or similar component inside - 13:22 Noticed a shielded cable connected to a PCB - 13:35 Opened a separate assembly on suspension - 13:46 Discussed the high impedance input stage and amplification circuitry - 14:39 Switched focus to the battery charge port - 14:46 Identified Nickelback high dried batteries - 15:03 Noticed three contacts likely for power and a temperature sensor - 15:13 Found a LED for visual indication - 15:26 Explored the Optical components - 15:39 Recognized an optical attenuator and mirrors for calibration purpose - 15:49 Identified a laser diode feeding into one of the fibers - 15:59 Discussed separating the receiving and transmit paths - 16:20 Noticed a small assembly for inverting mirror to compensate for the inversion of the optical system - 16:42 Explained the eyepiece and how it provides mechanical zoom - 16:54 Discussed infrared rangefinder optics - 17:02 Noticed a LED indicator for users - 17:10 Identified two fiber optics, a transmit laser, an oscillator, and a temperature compensated oscillator - 17:20 Proposed a hypothesis for the functioning of the system - 17:36 Identified an 805.1 based architecture microchip - 17:46 Discussed the highly sensitive optical receiver inside a can - 17:53 Noticed NE602 mix Ross later, a coil, and a couple of high voltage diodes - 18:00 Discussed the architecture, compared it to a radio receiver - 18:20 Discussed the placement of Optics and fiber, and mentioned the possibility of an avalanche photodiode for high sensitivity. - 18:20 Introduction of an angled reflector - 18:24 Discussion of the weather fiber optics - 18:28 Reflection off the front piece - 18:35 Presence of a coating on the reflector - 18:40 This coating acts as an infrared reflector to maximize output and reduce risk to the user - 18:51 Presence of an insert acting as an indicator - 19:01 This allows for visual indication when using the device - 19:10 Examination of the PCB and fiber optics - 19:13 Speculation that the transmission laser could potentially be a laser rather than a LED - 19:18 SIM for AC 540 acting as a high-speed driver - 19:28 Mention of two unidentified semiconductors with oscillators - 19:35 Presence of a temperature compensated oscillator - 19:40 Frequency measurement of the oscillator - 19:49 Discussion of laser range finding and the use of high frequencies - 20:01 Speculation about the presence of the same chip in both transmit and receive paths - 20:09 Consideration that this could be a custom chip with both receiver and transmitter functionalities - 20:36 Single chip micro 805.1 based architecture present, dating to 1996/1997 - 20:46 Analysis of the optical receiver - 20:53 Mention of an NE602 mixer - 21:00 Observation of a coil and high-voltage diodes - 21:08 Speculation that the device could be using an avalanche photodiode - 21:20 Explanation for why optics are put down a fiber rather than located in the optical system *Testing and Concluding Remarks* 21:49 Attempt to power the device using 12 volts 21:55 Observations on the device's response 22:03 Difficulty in determining RS232 commands 22:28 Mention of similar teardowns found on RUclips 22:43 Surprise at finding an inductive encoder 22:54 Mention of the high price of new models 23:01 Additional features on newer models like motorized axes and GPS 23:07 Mention of the device's robust build for use on construction sites 23:19 Uncertainty about the device's functionality without the front panel 23:27 Speculation about the possibility of operating the device entirely through RS232. Disclaimer: I utilized gpt4-8k 0613 to condense the video transcript into a summary. It generated timestamped bullet list and organized it into sections with titles. The summary was manually formatted using RUclips comment markup. I think the transcript has quite a few wrong words: 'course adjustment' should be coarse adjustment. 'nickelback high dried batteries' should be ' Nickel-metal hydride battery'. Ah well.
I wonder maybe the hearing aid in the bottom, could be to detect vibration from heavy construction. So the measurements no can be valid when it’s happening.
@@mikeselectricstuff It looks extremely similar to a Telex/Audio Implements IFB earpiece transducer used in broadcasting. They're usually about 500 ohms, and I don't get why they wouldn't use a standard beeper because those transducers are rather pricey.
two videos within three days?? Did i miss chirstmas?
It's great to have such an in-depth teardown of a total station, thanks Mike! The little widget on the top of the telescope is for the person operating the TS to get roughly in the right direction to point at the person with the staff - sight down the widget with both eyes open so the circle is full, and make coarse adjustments of the scope until the circle covers the top of the staff, then look through the scope and use the fine adjustment knobs to zero the crosshairs on the reflector. Normally the rodman's job is to hold the staff upright and in place and wait for the surveyor to shout that they've taken a reading. They need to keep an eye on the spirit level on the rod, and so won't be able to sight back to the TS. With staking-out (positioning the staff on a pre-computed point) the surveyor will set a known location and the TS will guide them up/down/left/right/back/forward, and they shout to the rodman to move until the reflector is in the right place. So in both cases the rodman's job is the more important - they need to choose the right location and keep as still as possible. The surveyor just needs one working eye, and the ability to press a few buttons.
The black and white part of the rotary encoder is for taking double-face shots. The surveyor will sight normally and take a reading, then they will flip the telescope and rotate the TS 180 degrees and take a second reading, the TS then averages the angles which eliminates any mechanical offset errors.
The ASCII chart is fascinating! The only thing I can think of is after looking at the control panel it only has numbers on it, so typing text requires the user to type in ASCII integers! That's batshit for '97! My TS is only a few years younger, and it has a speccy keyboard style alpha numeric keypad. While there's not a ton of text that needs typing - most of it can be set up in the office through the serial cable - there's enough to warrant a proper alpha keyboard.
We had a total station from about the same era at a job I worked on a few years ago.
The reason the front-panel/user-interface is removable is because it was effectively the storage disk for any measurements you took. The idea was you would detach it, carry it into the office, and plug it into a desktop PC which ran some accompanying software.
These things are extremely sensitive to level. The power-on process for the one we had involved it requiring you to do an extremely fine levelling procedure. You'd need to level the tripod using it's built-in level, and then that would get the overall level close enough for the internal sensor to work.
I spent some time writing software to get measurements from it. It had a ridiculously terrible serial interface, which would periodically lock-up and become unresponsive.
My Nikon TS from the late 90s/early 00s is also a painful device to use. It doesn't have a detachable keypad, so you have to lug the whole thing to the computer to do any comms. Thankfully I've not had any crashes with it, but it is still a faff to get what you want and then translate the output to something less ~batshit~ memory efficient.
I was once given a Spectra Physics “Dial Grade” pipe alignment laser, as a teenager. A fascinating unit. Way, way before the internet I would work my way through the “Yellow pages” asking for old or discarded equipment (that’s how I got my first ever job at 16, as a TV & VCR apprentice).
I sat up all night and took the “Dial Grade” apart on the sitting room carpet. I was new to taking things apart back then in the 90s; it was all so magical and exciting. I didn’t have a torx driver (they were mysterious, exotic things) and so persisted in forcing the security screws undone with ingenuity and brute force.
I still CLEARLY remember the beautiful iridescent shimmer of the thick red HeNe laser beam, and the prettiness of the light reflecting off the coated lenses and dichroic glass prisms.
I would clip the leads to a car battery next to my bed and shine it out across the fields so it hit the wooded area about a mile away.
Beautiful memories.
If the beam looked irridescent, that HeNe was an impressive HeNe indeed! Colors other than red are rare, especially as power increases and the higher gain lines start to dominate.
@@railgap shimmering is more apt. You’re spot on.
finally you are back! come back more often, your videos on disassembling electronics are unique, I look forward to seeing you again!❤🎉
"The ASCII table can be used to enter alpha characters directly from the keyboard on instruments with a numerical keyboard. This can be done with the help of the (ASCII) key.", from "Pentax total station operating manual". Cheers !
For the ASCII table - I've also seen them on old mobile road signs. The interface for entering the message is just a 3x4 keypad, so you enter ASCII directly. I assume people using this would also use those road signs.
I had an old label printer when I was a kid that worked the same way.
The NE602 is a mixer amplifier chip used in radios so you're probably right that it works via some hetrodyne RF technique.
Thank you for the tear down. Reduces my urge to tear mine apart. With careful battery change I think I can get some years of life out of mine when I learn to use it. The User interface on these units is abysmal with cryptic numeric command codes that made sense when the first total station was made and then the surveyors learnt the codes and did not want anything to change.
I'm reasonably sure that this was originally the Geodimeter brand that was purchased by Spectra Precision and then by Trimble.
The earlier units had a DE-9 connector and later a 4 pin so this case was perhaps made during the change over period.
The DE-9 connector has RS-232 or ASYNC TTL and power on non standard pins but not sure what the other contacts on the 6 way slip ring were for. I have a GDM424 Geodimeter unit that is before this one and this was probably one of the 500 or 600 series units, I think some model numbers were changed somewhat when the ownership changed (Trimble may have added 5000 to the model number).
The displays came in numeric and alphanumeric versions (cost cutting a keypad) so the ASCII table was to enable a numeric interface to easier enter alphanumeric names for the surveyed points.
The various units had either just calibration constants stored in the units with the battery backed ram or some of the 500, 4000 or 600 series units had the user interface program also RAM backed up. Earlier than the 400 units some had the fixed constants loaded into RAM memory as well that were the same for all units, perhaps they thought that some error in hardware or software could be compensated later by adjusting the speed of light to air density calibration. In the end all of these earlier units become doorstops if they loose their battery data because Trimble can no longer access the factory presets and except for one enthusiastic fellow nobody has any way to generate the calibration constants for the units. This amateur specialist might be happy to get copies of the ROMs for his collection.
The little telescopes are for coarse sighting for the operator. Some devices have a light beam they shine to the pole holder so he can point the prism (reflector) at the operator at the ranging station.
Some of the units with motorised sighting had detachable keyboards with radio link provisions, later units this was standard. The lone button was to take a reading when the unit was flipped over and the keypad was on the other side. Not much used on these because the factory calibration and the internal levelling (compensator) provided almost the full accuracy with just a single sighting. Some units could send voice signals to the pole holder via the measuring beam to an optical receiver attached to the pole with the prism.
I found a table that indicated some of the modulation frequencies used to calculate the ranging and while I did not follow why they were chosen it seems that there is some important reason. Here is a selection of the frequecies in Hz.
29970000
14985530
14985543
14984651
14984629
14985453
14987103
14987090
14983482
14985400
These were from 4 manufacturers including some Geodimeter but not these particular units where cryptic notes hints at the reason.
Note (i)
The carrier wavelength can vary between 850nm and 910nm due to the use of different types of diodes from various sources
Note(j)
The manufacturer selects the modulation frequency (~15 MHz) according to the actual carrier wavelength (as well as the 10M unit length) so that the same C and D terms can be used for all instruments
The "Terms of first velocity correction" indicated as C=275 and D=79.55 are the same for all but the very early Geodimeter total stations. Other vendors have different constants. Geodimeter also has their "Reference Refractive index" = 1.00275 for later units, other vendors have different values.
"?" gives a command list on some units.
Someone called mike1202 offered the following serial commands,
"OV*" - dump memory,
"RV,100" - GDM model
"RV,110" - loader time and date
"RV,111"- GDM serial number
"RV,113" - program version
Some others can clear all RAM memory
The open source project is on GITHUB user ROBOTS project GDM I think that may be the same user that provided the command list above.
The empty space behind the one side panel is for an optional extra battery compartment or an optional radio link.
The hole in the battery compartment where the logo is visible is where the TrackLight would shine for the "rod man" to know where the operator is standing so he can orient the prism appropriately. The TracklLight is cool because it changes colour like glide slope indicators at a runway. The station operator can point to where he wants a measurement to be made and then the rod man can move along a line to the point where the light changes colour from red or green on the sides to white in the middle.
The 600 series came out in 1994 with the models 610, 620 and 640
You can see a lot of history in a document.
Search for "The History of Geodimeter J.R. Smith"
Hi Mike. Thanks for another really interesting vid. you always get some rarely available stuff and show us curious folks a really good look around inside and out.. from menial to mega complex, with good descriptions to help us understand what we are seeing. Love this channel. Thanks Mike. :)
I worked at Tripod Data Systems (now Trimble) and we sold quite a few of these, although they were branded as Nikon. I never got to take any apart though!
Nice! That little laser diode probably pushes out a 100W or so in a few hundred nanoseconds.
regarding the strange positions of the pins in that photodiode package, it looks like that puts one pin in the center of the package, so I would guess the actual photodiode die is mounted to the face of that pin. That would provide some improvement in package parasitics versus the other method of mounting the die to a shelf in the can base and bonding it out to the pins. The latter method is more common in laser diodes for better thermal coupling of the die to the can, but means the diode is either electrically bonded to the can or is capacitively coupled to the can via an insulating layer. Putting the die on the face of a central pin isolates the diode entirely from the can without the capacitive coupling and eliminates one set of bond wires.
The only reason I can think of for the ASCII table is that on average, it is likely faster to type in the B10 ASCII codes than it would be to type it in flip-phone texting style. The learning curve would be a lot higher though.
The 'load' bearing on the foot probably isn't there for taking load, as the other bearing would be more than enough to do so. It's my guess it's for better precision by taking out any possible wobble from the other bearing.
Very nice I've always wanted to see a total station tear-down. I've only read about inductosyn encoders, never seen one dismantled. For getting down to 1 second of arc it has an impressive lack of poles, so most of the resolution is from phase measurement. Yes I suspect the coarse optical is for absolute ambiguity removal. I wonder if they calibrate the encoder to remove its stationary non-idealities rather than relying on precision construction and alignment?
Making it with PCB will be pretty accurate to start with
@@mikeselectricstuffthanks for this teardown , they are a linear version of this encoder found in digital caliper .
@@labiadh_chokri Indeed! And I am amazed how accurately even the cheap ones can discern the _tiniest_ movements
The ASCII table is likely useful because they didn't have the option to press a number several times to get 'abc', 'def' etc, like on a 90'es cellphone (before T9 dictionaries). Even though the date codes say 1997 the design is likely much older
I worked at an engineering company that used total stations. It's high precision stuff because they would use such a device in multiple steps into a long tunnel to get the "GPS" coordinate of the end so if you want to have mm precision 1km down you need precise angles. I wonder if the encoder could be done with a passive rotor with a tab that changes a wave guide length and use RF and phase detection. That way you have a single location for electronics and presumably inexpensive. time of flight should be fairly reliable, maybe air density compensation. With clever arrangement a single emitter might be able to determine the angles of multiple encoders. That would be kind of neat.
It's called total station becauae it makes angular and distance measurements, error calculations and mapping calculations all within this single instrument in contrast with traditional geodesy methods.
I've wanted a basic digital theodolite (don't really need GPS, but a rangefinder would be nice) for ages... despite not actually having a dire need for one. :) They can be quite handy, even indoors in a machine shop!
The hand held laser range finders that you can get for EUR30 at the hardware store are remarkably convenient though limited in range and probably accurate to about 10mm.
With used total stations you get a little more accuracy and the angle readings but the old units are a gamble if they break or have lost their RAM battery voltage. Some units loose constants, calibration or even firmware.
as a surveyor, this was interesting to watch!
Don't turn it on! Take it apart :P Sorry I had to say it to your expensive gear!
Is this angle sensor perhaps a type of resolver? CuriousMarc has done some episodes on them, and I think they are really cool.
When Mike mentioned inductive sensing via a transformer, the first thing I thought of was a resolver. I have an old CNC that uses those for position feedback.
From the looks of it, it's probably an Inductosyn - very similar to a resolver, but with a lot more poles for increased accuracy.
I think it's pretty similar, though looks like it has more secondary windings for increased resolution
It looks like a theodolite that we use to align precision aircraft optics . Digital data is sent to an external computer to calculate/display pass/fail criteria. The device we use was sourced from a major UK company.
Welcome in the very private club of youtubers who teardown total stations 😂 The name of total station might be because it does the job of a theodolite + the job of a telemeter + the computations, so basically the work of formerly several different devices.
your channel also looks super interesting! subbed!
Yes I was thinking the same, but wonder if it started with one manufacturer's product and then became a general term, like Hoover for vacuum cleaner ( in the UK at least) . Great channel BTW.
@@mikeselectricstuff probably Leica, they were I believe the first company to really push the concept
Awesome video Mike! Fascinating technology 0.0
...Looks like an older vintage Geodimeter 600 rebranded-purchased under Spectra, Trimble names, A Trimble 5600 with out radio-remote servo's, late 90's unit... Front control panel plate is easy to find on-line.
The mug design is excellent. :)
Agreed!
Seeing the split lens reminded me of an old non electronic theodolite i was shown, iirc, when the theodolite is perfecty horizontal, a line in each side lines up with each other.
i remember being taught how to do that manually at uni. sum the back sights, sum the fore sights and some of us cocked it up completely!
You’ve got it backwards. Those little sights aren’t for the guy holding the prism. They’re for quick rough sighting by the instrument man. Look at them from the eyepiece end and you’ll see an arrow that you can then line up with the target.
pretty sure that if object is in the middle on all axii, the accuracy end is where ever you point it. not which side you look through. if you look thru the wrong end and still get it all lined up, thats jedi master level skills territory 😂🤣
@@Palmit_ it’s a lens assembly, it not just a tube with a mask in the middle. I have them on a couple total stations and theodolites. When viewed from the eyepiece end, the arrow can be seen very clearly.
if you want i have an control panel for it.
thats awesome.. but can mike put it all back together ? @mikeselectricstuff
Hey ! Good day to you ! I was wondering if you can and want to do some video about that new "Sphere" in Las Vegas, if is so good as they say and what is needed to power it and manage all that amount of data. Cheers !
I would keep that slip ring assembly. It will be worth its weight in gold to someones project!
That’s the rationale all hoarders use 😂😂😂😂
@@unlokia OOh yes got it in one !
ooh. quick question. the magnifier thingy @17:45 just behind the back of the chair. Can you tell us .. What is it's name and where can i get one?
It's a mantis stereo microscope. So, so good to use, and expensive, very expensive...
@@xtevesousa thx! :) yes.... they dont even give a price, only give you chance to ask how much .."request quote"
@@Palmit_ I paid £1K new - they do come up on ebay occasionally. Way better than a stereo microscope
Two videos in one week! And phenomenal taste in teardown equipment, as usual. **chef's kiss** 🤌
Fascinating to see Soo much analog goodness.
I have not received your book and would like a refund
@@TimPerfetto my book?
@@zaprodk How do I receive a refund
Wondering if that position sensing device is actually a high-precision resolver?
That's what I was thinking too.
Also what I thought. Resolvers usually are a bit more heavy duty but this might be based on the same principle.
'splain "resolver" pls.
@@Palmit_ in short, a magnetic coil that sends voltage back as position. It’s much more complicated than that, though.
Nice, been curious about these since I've first seen them.
interesting bit of kit. Great video 2x👍
Howdy Mike well pleased cheers!
its an EDM theodolite :) i used them plus levels as my life as a chain boy ~:) cool bits of kit
I reckon comms issues are probably some strange protocol used in the device; For it's application it's nothing to be expected, back in the day EE's just used whatever they liked that met the project specs.... I laugh because I like how Mike always tries to follow a logical layout within his own designs and something worth taking on board in electronics design.
It can surely be decoded and reverse engineered. It just takes time, and Mike does not have infinite amount of time to do it.
@@movax20hSomeone has done it. See my other comment.
Any news on the ASCII table yet?
On the image with the user interface i noticed it basically only has numbers. Maybe it was to enter text because they didn't bother implementing a complicated UI for it.
If you google image Precision Constructor Total Station you can see the detachable keypad/memory device and it only has a number pad + a few extra keys
Hey Mike, just wanted to ask if your going to be at Gaussfest this year? I've been watching your channel for 12 years now and it would be cool to meet you mate, thanks in advance
Steve... 👍👍
No - will be at Supercon then
@@mikeselectricstuff oh okay mate, thanks for the reply, maybe our paths will cross at some point, 👍👍
Steve
مرحبا سيد ستيف
لاحظت انك ذو خبرة كبيرة
أود أن أسألك عندي جهاز تريمبل5600 قديم بدون راديو موديل عام 2001
اريدطريقة قياس مسافة او زاوية
هل تستطيع مساعدتي
Best mug ever!
Finally! Thank you
thanks Mike :)
Pretty cool. I was also quite surprised they didn't use absolute optical encoders. But analog could also be cheaper. Interesting never the less.
I've always wondered how these work!
Always wanted to make one into a security robot with a blinding laser light for intruders 😂
Whats the french channel that tears down military stuff?
www.youtube.com/@msylvain59
@@FixitFrank Also www.youtube.com/@lelabodemichel5162 - he goes extreme - tracing out schematics & getting stuff working
@@mikeselectricstuff amazing, thanks.
Tacheometer?
Maybe those encoder thing is like those on digital caliper that bigclive teardown
No, those are capacitive. this is inductive
@@mikeselectricstuff ah... That's why it has bars not coils. Thanks.
that mug tho...
Maybe they use an inductive encoder since its an absolute device, never lousing zero?
Optical encoders can also be absolute. As Mike mentions, it can be a way to circumvent a patent.
Optical encoders often have an index mark but they usually don't give you an absolute position "cold". You have to pass the index point and then count ticks from there.
Versus a magnetic device that gives you sin/cos outputs that you can always get the abs position from.
This appears to be neither, however.
@@rfmerrill
Yes with an optical encoder on power on you would have to rotate the head through the index mark. Have used an absolute optical encoder but they are very complex and expensive for high resolution.
This looks like a large PCB based RVDT.
Or it just might just be PFM
Sure, quadrature optical encoders aren't usually used for absolute positioning since you would need to have some sort of indexing, but Gray code encoders will give absolute position right off.
@@frtard
For 8 bit resolution there would be 8 sets of tracks, emitters and detectors. gets really ugly at 16 bits.
*Summary*
*Introduction and Basic Features of Geodometer*
0:00 - Introduction to a geodometer, also known as a total station
0:16 - The device is used for surveying buildings, roads, etc.
0:23 - The geodometer maps out positions of objects in 2D and 3D space
0:33 - Features include a laser range line and a telescope
0:52 - The device maps out an area by measuring angular positions and distance to an object
0:59 - Initially assumed this would be a remotely operated model
1:37 - The model appears to be a standard manual one without the user interface or computer panel
1:53 - Expectation is for high precision angular measurement and laser rangefinder
1:56 - The geodometer is a Spectra Precision Constructor
2:13 - Differences between different brands would likely be in precision
2:23 - The ASCII code table on the front of the device is puzzling
*Physical Features of the Device*
2:52 - Bottom part of the device is the battery
3:00 - The battery also serves as counterbalance
3:12 - There are various knobs on the side and the bottom of the device
3:16 - The device features a telescope with a focus adjustment
3:26 - Telescope is of high-quality and long-range zoom
3:34 - There is a button on the front of the device
3:38 - Alignment aids on top and bottom help the person at a distance to line up with the lens
4:28 - The device features a 4-pin connector possibly for power and RS232
4:38 - There is a connector for a user interface or a computer that does calculations based on the angles and distances
4:44 - The device features an interconnect board and a push button on the front
4:46 - The side panel features an encoder, an 80c32 processor, external prom, and some RAM
6:03 - Inductive coils and opto reflective sensors provide high resolution output for angle measurement
7:14 - The encoder is connected directly to the rotating sensor
7:45 - The encoder provides both absolute position reference and a high-precision output
*Further Investigation and Component Details*
9:29 - There is a PCB inside the cover with a couple of backup batteries
9:38 - The device features two knobs for adjusting each axis
10:01 - The device features a Sounder.
(10:04 - 21:20: Details about components identified and their functionalities are discussed)
- 10:04 Discussed a hearing aid type called Sounder
- 10:08 Spotted a unique object
- 10:11 Noticed several components including a 87c51 single chip micro, ram ewart chip, rs232 drivers, and analog switching
- 10:29 Noticed power supply components and batteries
- 10:31 Suggested batteries could be backing up the Ram and discussed user interface
- 10:37 Noticed an inductor, believed to be associated with the power supply
- 10:41 Discussed knobs and their functions
- 10:47 Explained the process of course and fine adjustments using the knobs
- 11:09 Suggested it is a way of providing course adjustments
- 11:19 Noted similar functions for the rotation axis
- 11:24 Introduced a locking mechanism
- 11:41 Identified a similar type of encoder seen on the vertical axis
- 11:47 Noticed a sensor connection, believed to be used to generate the field for the Central rotor
- 11:57 Suspected the connector may be part of a slip Ring Time arrangement
- 12:03 Saw a fuse which is likely for the power connection
- 12:13 Suggested different versions may exist based on outdoor usage
- 12:25 Noticed a slip ring assembly at the bottom
- 12:34 Discussed the load bearing system
- 12:39 Noted heavy plated copper for the slip rings on the PCB
- 12:47 Noted duplicate tracks and contacts for redundancy
- 13:05 Suspected a module to be a level sensor
- 13:16 Predicted a ball or similar component inside
- 13:22 Noticed a shielded cable connected to a PCB
- 13:35 Opened a separate assembly on suspension
- 13:46 Discussed the high impedance input stage and amplification circuitry
- 14:39 Switched focus to the battery charge port
- 14:46 Identified Nickelback high dried batteries
- 15:03 Noticed three contacts likely for power and a temperature sensor
- 15:13 Found a LED for visual indication
- 15:26 Explored the Optical components
- 15:39 Recognized an optical attenuator and mirrors for calibration purpose
- 15:49 Identified a laser diode feeding into one of the fibers
- 15:59 Discussed separating the receiving and transmit paths
- 16:20 Noticed a small assembly for inverting mirror to compensate for the inversion of the optical system
- 16:42 Explained the eyepiece and how it provides mechanical zoom
- 16:54 Discussed infrared rangefinder optics
- 17:02 Noticed a LED indicator for users
- 17:10 Identified two fiber optics, a transmit laser, an oscillator, and a temperature compensated oscillator
- 17:20 Proposed a hypothesis for the functioning of the system
- 17:36 Identified an 805.1 based architecture microchip
- 17:46 Discussed the highly sensitive optical receiver inside a can
- 17:53 Noticed NE602 mix Ross later, a coil, and a couple of high voltage diodes
- 18:00 Discussed the architecture, compared it to a radio receiver
- 18:20 Discussed the placement of Optics and fiber, and mentioned the possibility of an avalanche photodiode for high sensitivity.
- 18:20 Introduction of an angled reflector
- 18:24 Discussion of the weather fiber optics
- 18:28 Reflection off the front piece
- 18:35 Presence of a coating on the reflector
- 18:40 This coating acts as an infrared reflector to maximize output and reduce risk to the user
- 18:51 Presence of an insert acting as an indicator
- 19:01 This allows for visual indication when using the device
- 19:10 Examination of the PCB and fiber optics
- 19:13 Speculation that the transmission laser could potentially be a laser rather than a LED
- 19:18 SIM for AC 540 acting as a high-speed driver
- 19:28 Mention of two unidentified semiconductors with oscillators
- 19:35 Presence of a temperature compensated oscillator
- 19:40 Frequency measurement of the oscillator
- 19:49 Discussion of laser range finding and the use of high frequencies
- 20:01 Speculation about the presence of the same chip in both transmit and receive paths
- 20:09 Consideration that this could be a custom chip with both receiver and transmitter functionalities
- 20:36 Single chip micro 805.1 based architecture present, dating to 1996/1997
- 20:46 Analysis of the optical receiver
- 20:53 Mention of an NE602 mixer
- 21:00 Observation of a coil and high-voltage diodes
- 21:08 Speculation that the device could be using an avalanche photodiode
- 21:20 Explanation for why optics are put down a fiber rather than located in the optical system
*Testing and Concluding Remarks*
21:49 Attempt to power the device using 12 volts
21:55 Observations on the device's response
22:03 Difficulty in determining RS232 commands
22:28 Mention of similar teardowns found on RUclips
22:43 Surprise at finding an inductive encoder
22:54 Mention of the high price of new models
23:01 Additional features on newer models like motorized axes and GPS
23:07 Mention of the device's robust build for use on construction sites
23:19 Uncertainty about the device's functionality without the front panel
23:27 Speculation about the possibility of operating the device entirely through RS232.
Disclaimer: I utilized gpt4-8k 0613 to condense the video transcript
into a summary. It generated timestamped bullet list and organized it
into sections with titles. The summary was manually formatted using
RUclips comment markup.
I think the transcript has quite a few wrong words: 'course adjustment'
should be coarse adjustment. 'nickelback high dried
batteries' should be ' Nickel-metal hydride battery'. Ah well.
I wonder maybe the hearing aid in the bottom, could be to detect vibration from heavy construction. So the measurements no can be valid when it’s happening.
No, it's just a beeper. Maybe waterproof
@@mikeselectricstuff lol.. or one of those heavy goods vehicle sounders.. " attention, this tripod is falling over"
@@mikeselectricstuff It looks extremely similar to a Telex/Audio Implements IFB earpiece transducer used in broadcasting. They're usually about 500 ohms, and I don't get why they wouldn't use a standard beeper because those transducers are rather pricey.
I know who you mean, mysylvain
:D
Inductosyn
Hi, so today we have a comment on your video.
o/