Since I got asked multiple times here are some recommendations for C cal and C12. For C_cal I used: 1 nF / Styroflex capacitor / Axial / Rated Voltage: 160 V DC / Tolerance: 2 % / Dimensions: Ø 4.5 mm , Length 11.5 mm I bought it from here: www.reichelt.de/de/en/styroflex-capacitor-1-0-n-2--styroflex-1-0n-p19837.html?GROUPID=3158&START=0&OFFSET=16&SID=92fe968488052b504d180a23f581dc98fa3e05d01bdc62094114f&LANGUAGE=EN&&r=1 For C12 I used: 1.0 nF / Film capacitor (WIMA: Series FKP 2 / Dielectric PP film / Capacitor electrodes Metal foil) / Rated Voltage: 630 V DC / Dimensions: Pitch 5 mm , Length 7.2 mm , Width 4.5 mm , Height 6.0 mm / Tolerance: 2.5 % I bought it from here: www.reichelt.de/de/en/wima-film-capacitor-rm-5-mm-1-0-nf-fkp2-630-1-0n-p31942.html?&trstct=pos_0&nbc=1 These are both ok. However, I would recommend this capacitor due to its lower tolerance / better precision: 1.0 nF / Mica capacitor / Radial / Rated Voltage: 100 V DC / Tolerance: 1% / Dimensions: Pitch 4.5 mm, Length 8.5 mm, Height 5.0 mm, Width 7.0 mm You can buy it here: www.reichelt.de/de/en/mica-capacitor-1-0-nf-100-v--1--cy-22-3-1-0n-p42441.html?&trstct=pol_0&nbc=1
I'm looking forward to make an LC meter inspired by this wonderful design. One thing I would like to change in order to improve the meter is to add a flyback diode across the reed relay coil, just like the D2 diode
Nice project! I really appreciated the clarity of your hand drawn circuits and your complete explanation of all of the circuit modules. Thank you for your valuable addition to open source projects.
Glad you enjoyed it. Please leave a like and subscribe to this channel, it would mean a lot to me ! I have other vids too, and many more are coming. Try browsing through my channel's content and tell me if you liked something in particular. Thanks !
I came across your project and it is exactly what I was looking for. It is very well explained and thank you for sharing your designs. A quick question, what is the lowest capacitance value that your design can detect? I am looking for capacitance range of 1pF and up. Thanks
Quick answer to your question: if you work carefully, make good solder joints, clean your board, make sure there are no residues, use short / good quality measuring leads and probes, and most importantly use small tolerance parts (especially the two precision capacitors) you will be able to measure 1pF caps with very good precision. Thanks for watching.
@@coreWeaver That's great. I just watched your 4th video where you measured 2pF capacitor which is what I am after. Not sure if you have 0.1pF capacitor or similar, would you be able to measure tiny capacitances less than 1pF with your design as well? I think better question would be, what is the lowest value of capacitance can you measure. Also, do you accept donations?
@@davidnorman3000 I only tested till 1pF. I suppose I could try measuring a series capacitance of 2 x 1pF which should read 0.5pF. I'll also have to check the firmware first. I can't remember how that "converting to engineering units" subroutine works. I'm not sure it will display something smaller than 1 for the pF domain. I'll get back to you on that. As for donations, I don't have patreon yet, only paypal. If you want send me an email at: core.weaver@gmail.com. Thanks
@@coreWeaver that's great. Thanks. I am building some interdigital electrode sensors to measure moisture in soil, for which I will be providing a sinusoidal signal to the sensor and use your design to measure its capacitance with different levels of moisture. If possible, would you be able to recommend how to adapt your design for sinusoidal signal instead of a square signal?
I am curious why you used a 7805 rather than a 5v LDO. The LM7805 requires at least 3v of headroom so if 9v battery drops below 8v then the 7805 may not regulate. Also why did you use a LM317Z and 1% resistors rather than using a LP2950Z-3.3 or other 3.3v LDO as it is hard to get right resistors for LM317 and the Nokia display has a max voltage that could potentially be exceeded. Thank you for a very nice project. I am trying to upload the 1.6mm case files to JLCPCB but they keep saying the filename is too long and exceeds the 30 character limit (even though most do not exceed 30 characters). I dropped the same files into a online 3D viewer and it viewed correctly. Do you have the Case files uploaded to them of PCBWay or Seeed Studios so we can just pick them? Thank you.
You're right about the 7805. There are better choices for the regulator. I used despite its disadvantages you mentioned, because it's readily available, it's easy to source, and not expensive. The LM317 and the 1% resistors I had available, and yeah there are other ways to do the 3V3. The project is open source so anyone can modify the schematic. As for the Case files I never used a fab house to manufacture the case so I can't tell you what's wrong. Just a thought. Use the STL to export in whatever format your printer will recognize and save the files with shorter names.
Would 1% MLCC capacitor work you think? Is there any more details you can give on the design of the opamp circuit? I am also wondering if any other circuitry could be added to do a primitive ESR measurement.
I think so. MLCC are very good quality nowadays. Try getting X8R or X7R. The LM311 is a high speed - voltage comparator. At t0, there's 2.5V on the non-inverting input and 0V on the inverting input. So the output (pin 7) will be high, which causes c10 to start charging through R19, which will cause then the comparator's output to get low again... The process repeats itself with a frequency equals to the resonant freq. of the L1 - C12 pair. As for the ESR, it will need some additional external circuitry. I will add it in a future version.
Why not just display the mode (L, C, or CAL) on the LCD instead of using the two LED's? Also, the atMega328 will run fine at 8 MHZ from a 3.3 volt supply, so there isn't any need to run it at 5 volts which would simplify the power supply. The relays might not work at 3.3 v, however I think that relays with a lower coil voltage are available, or they could be powered from before the 3.3 volt regulator.
I hope it's not too late, I just saw your message. Yeah it's possible to use a normal 5V relay instead of the reed relay. You should use a transistor though. The AVR can only sink 20mA @5V per I/O pin.
@@coreWeaver its never late. Actually i have learned so many things about avr after watching your video. I wanted to be 100% about this project. and i have collected all the parts accordingly . I have modified your pcb eagle file a little to make it at home, but i failed 2nd time. I belive in my 3rd trial i can finish this. Now i am on vacation, after finishing i'll inform you... Thank you.
all the documentation and also the sw are available here: hackaday.io/project/178081-build-an-lc-meter and here: github.com/coreWeaver/LC-Meter If you need help send me an email. Thanks for watching. Don't forget to subscribe.
Since I got asked multiple times here are some recommendations for C cal and C12.
For C_cal I used:
1 nF / Styroflex capacitor / Axial / Rated Voltage: 160 V DC / Tolerance: 2 % / Dimensions: Ø 4.5 mm , Length 11.5 mm
I bought it from here:
www.reichelt.de/de/en/styroflex-capacitor-1-0-n-2--styroflex-1-0n-p19837.html?GROUPID=3158&START=0&OFFSET=16&SID=92fe968488052b504d180a23f581dc98fa3e05d01bdc62094114f&LANGUAGE=EN&&r=1
For C12 I used:
1.0 nF / Film capacitor (WIMA: Series FKP 2 / Dielectric PP film / Capacitor electrodes Metal foil) / Rated Voltage: 630 V DC / Dimensions: Pitch 5 mm , Length 7.2 mm , Width 4.5 mm , Height 6.0 mm / Tolerance: 2.5 %
I bought it from here:
www.reichelt.de/de/en/wima-film-capacitor-rm-5-mm-1-0-nf-fkp2-630-1-0n-p31942.html?&trstct=pos_0&nbc=1
These are both ok. However, I would recommend this capacitor due to its lower tolerance / better precision:
1.0 nF / Mica capacitor / Radial / Rated Voltage: 100 V DC / Tolerance: 1% / Dimensions: Pitch 4.5 mm, Length 8.5 mm, Height 5.0 mm, Width 7.0 mm
You can buy it here:
www.reichelt.de/de/en/mica-capacitor-1-0-nf-100-v--1--cy-22-3-1-0n-p42441.html?&trstct=pol_0&nbc=1
Watching brings back old memories of doing this type of things for a living as a hardware / software engineer in industrial environment.
if you one day feel like wanting to share some of those memories, I'm always down for a good story :)
I'm looking forward to make an LC meter inspired by this wonderful design.
One thing I would like to change in order to improve the meter is to add a flyback diode across the reed relay coil, just like the D2 diode
Nice project! I really appreciated the clarity of your hand drawn circuits and your complete explanation of all of the circuit modules. Thank you for your valuable addition to open source projects.
Glad you enjoyed it. Please leave a like and subscribe to this channel, it would mean a lot to me ! I have other vids too, and many more are coming. Try browsing through my channel's content and tell me if you liked something in particular. Thanks !
Your exclamations are very thorough and appreciated.
You won a PCB. Contact me at: core.weaver@gmail.com to clear out the details.
@@coreWeaver just emailed, hopefully I'm not too late.
A masterpiece 👨🎓. My RESPECTS 👏
thanks a lot
Thanks a lot for the explanation. Do you sell this finished board? or KIT? is so, How can I order it?
core.weaver@gmail.com
I came across your project and it is exactly what I was looking for. It is very well explained and thank you for sharing your designs. A quick question, what is the lowest capacitance value that your design can detect? I am looking for capacitance range of 1pF and up. Thanks
Quick answer to your question: if you work carefully, make good solder joints, clean your board, make sure there are no residues, use short / good quality measuring leads and probes, and most importantly use small tolerance parts (especially the two precision capacitors) you will be able to measure 1pF caps with very good precision. Thanks for watching.
@@coreWeaver That's great. I just watched your 4th video where you measured 2pF capacitor which is what I am after. Not sure if you have 0.1pF capacitor or similar, would you be able to measure tiny capacitances less than 1pF with your design as well? I think better question would be, what is the lowest value of capacitance can you measure. Also, do you accept donations?
@@davidnorman3000 I only tested till 1pF. I suppose I could try measuring a series capacitance of 2 x 1pF which should read 0.5pF. I'll also have to check the firmware first. I can't remember how that "converting to engineering units" subroutine works. I'm not sure it will display something smaller than 1 for the pF domain. I'll get back to you on that.
As for donations, I don't have patreon yet, only paypal. If you want send me an email at: core.weaver@gmail.com. Thanks
@@coreWeaver that's great. Thanks. I am building some interdigital electrode sensors to measure moisture in soil, for which I will be providing a sinusoidal signal to the sensor and use your design to measure its capacitance with different levels of moisture. If possible, would you be able to recommend how to adapt your design for sinusoidal signal instead of a square signal?
ruclips.net/video/OS8h7cKJdKs/видео.html hope this helps. I guess you could go lower than 0.2pF, but the measuring precision will drop more
I am curious why you used a 7805 rather than a 5v LDO. The LM7805 requires at least 3v of headroom so if 9v battery drops below 8v then the 7805 may not regulate. Also why did you use a LM317Z and 1% resistors rather than using a LP2950Z-3.3 or other 3.3v LDO as it is hard to get right resistors for LM317 and the Nokia display has a max voltage that could potentially be exceeded. Thank you for a very nice project. I am trying to upload the 1.6mm case files to JLCPCB but they keep saying the filename is too long and exceeds the 30 character limit (even though most do not exceed 30 characters). I dropped the same files into a online 3D viewer and it viewed correctly. Do you have the Case files uploaded to them of PCBWay or Seeed Studios so we can just pick them? Thank you.
You're right about the 7805. There are better choices for the regulator. I used despite its disadvantages you mentioned, because it's readily available, it's easy to source, and not expensive. The LM317 and the 1% resistors I had available, and yeah there are other ways to do the 3V3. The project is open source so anyone can modify the schematic. As for the Case files I never used a fab house to manufacture the case so I can't tell you what's wrong. Just a thought. Use the STL to export in whatever format your printer will recognize and save the files with shorter names.
Would 1% MLCC capacitor work you think? Is there any more details you can give on the design of the opamp circuit? I am also wondering if any other circuitry could be added to do a primitive ESR measurement.
I think so. MLCC are very good quality nowadays. Try getting X8R or X7R.
The LM311 is a high speed - voltage comparator. At t0, there's 2.5V on the non-inverting input and 0V on the inverting input. So the output (pin 7) will be high, which causes c10 to start charging through R19, which will cause then the comparator's output to get low again... The process repeats itself with a frequency equals to the resonant freq. of the L1 - C12 pair.
As for the ESR, it will need some additional external circuitry. I will add it in a future version.
Why not just display the mode (L, C, or CAL) on the LCD instead of using the two LED's?
Also, the atMega328 will run fine at 8 MHZ from a 3.3 volt supply, so there isn't any need to run it at 5 volts which would simplify the power supply. The relays might not work at 3.3 v, however I think that relays with a lower coil voltage are available, or they could be powered from before the 3.3 volt regulator.
which capacitor type is used for claibration? please. can it be replaced with ceramic ??
you need the smallest tolerance, precision cap (1000pF) you can find.
is it possible to use 5v relay instead of reed relay??
I hope it's not too late, I just saw your message. Yeah it's possible to use a normal 5V relay instead of the reed relay. You should use a transistor though. The AVR can only sink 20mA @5V per I/O pin.
@@coreWeaver its never late. Actually i have learned so many things about avr after watching your video. I wanted to be 100% about this project. and i have collected all the parts accordingly . I have modified your pcb eagle file a little to make it at home, but i failed 2nd time. I belive in my 3rd trial i can finish this. Now i am on vacation, after finishing i'll inform you... Thank you.
@@RepairRadioLab send me an email I might be able to help you out: core.weaver@gmail.com
what kind of compiler do you use?
Where is the schematic and parts list posted? I do not see it on your github page.
github.com/coreWeaver/LC-Meter/tree/main/LC%20Meter%20v1.0/1.%20Schematic%20and%20Gerber%20UPDATED%20Apr.08%2C%202021
Could I have your microcontroller firmware ? : ) because I don't have your LCD display and I want to change it to use another type of display .
Oh! Sorry , I know how to get the firmware now .
all the documentation and also the sw are available here: hackaday.io/project/178081-build-an-lc-meter
and here:
github.com/coreWeaver/LC-Meter
If you need help send me an email.
Thanks for watching. Don't forget to subscribe.
May I ask what type of capacitor you used for C_Cal and C12 ? Thank You !
see the pinned comment
what pcb software do you use, thank you
He is using Eagle
David Norman is right
Your exclamations are very thorough and appreciated.🙏
thanks !