You could've put common pin on the other row of pins. That way you would have the common fitting into the power lines directly (maybe with some little bending) without having to use that link on the side of the chip.
Funny there is not a lot of info out there on using SIL's. I have been building devices that use 8-10 LED's and using a LOT of resistors, where one or two SIL's would work. With that in mind I purchased a variety box of SIL's from the Electronic Goldmine online. It arrived with over 100 SIL's now the problem is figuring out what each one is in value. They have all sorts of markings due to various makers and designs, I think I have sort of figured out most of them now, it looks like it should
If you increase the led current a lot, you'll probably have problems with voltage dropping. Memory chips or logic chips can supply a very limited current. This creates problems with other chips not getting correct levels due to excessive current draw. Actually I'm supprised that it works even currently! To be safe, you'd better use a buffer to isolate leds from the logic level bus.
Being a couple of jumps ahead here, wanting the create my own 8bit breadboard computer, based on the videos from Ben Eater et al. and wanting to show the the address and databus inputs you are currently prototyping, I came across the same scenario with these 10bit bar graphs: I tested a number of SIL resistor networks and found the best turned out to be 330R for both 3.3v and 5v. I know you said you'd try the 330R SIL and I think you'll find it's the best option for a good brightness level.
Blue LEDs put out hundreds (thousands?) of times more photons than red LEDs for the same current. Using higher value resistors for the red and lower for the blue will increase the difference. I use resistors on the Blue LEDs that are 10 times the value of the red ones, and they're still noticeably brighter (but much less distracting).
The parameter of the side at which the common ground pin sits is the same parameter as the side to which the pins hang, as you can simply rotate the board for the pins to hang to the other side, with the only difference being that the common ground ends up at the right side instead of left (or the other way round)
You should try making a DIL package yourself, by getting those square LEDs(i forget the name) and attaching all the elctronics, aligning it inside the casing and pouring on resin. That would be interesting!
The more current you draw from those pins the more issues you are gonna have. Best off using a high value resistor so LED just lights up. Unfortunately this is rather camera unfriendly. Maybe other adjustments can be made but as you multiply the setup there gonna be trigger and voltage issues later. Like video, like the bar graph idea.
Julian, According to the data sheets 74LS gates and counters can sink a maximum current of 8mA (16ma for some) but maximum source current is only 400uA so sourcing current to the LEDs is very bad design practice. Saying "It seems to work OK" is promoting bad practice.
Nice project Julian! Two things: 1) You do know bar with upper pins and common left IS the same as a bar with lower pins and common right? ;) Aka, only two types 2) Blue leds indeed have a higher drop thus need a lower resistance for the same amount of current. BUT, blue leds tend to be a lot brighter with the same amount of current then the normal red leds... So 13mA (150Ohms) for the blue ones just makes them reaaaallllyyy bright and swamp the camera. The reds look just fine! Just use more like 2mA to 5mA for the blues to match :)
the extra leds might be useful for visualizing carry but if Julian gets around to building ALU. or maybe a Status register display which would have all of those extra bits (carry, zero, overflow, etc) but I'm now curious which architecture he's going for
I might have gone "old school" & put 2 wraps of wire wrap wire on the SIP common pin & the LED array lead it goes to; Gives the solder something to be attracted to + a good mechanical & electrical connection (compared to some other methods)
Hey Julian, can you please make a Fade-in Fade-out LED (Strip) Dimmer and sell the kit on your site or put an affiliate link so we can buy the parts? THANKS!!!
I noticed that the LED's on the right were considerably brighter then the ones on the left. Does that indicate the resistor pack has resistance across the common buss? Otherwise it should have the same amp draw across each LED no matter how many are lit. Especially considering it is tied directly to the negative terminal. I did not see the blue LED's changing in output so it is not a supply issue. Hmm
I think the brightness difference you are seeing is an artifact of the camera angle. If you watch the video before the red tape is placed over the LEDs there doesn't appear to be any difference.
Nice idea. If only IC sockets had nice long pins like these displays have. The pins on these displays are long enough that I can angle the displays forward a little which makes them easier to see.
Next time, tin the SIP leads before you put the package between the pins of the display. Also, clip the 3 leads so they're not in the way when soldering up.
I thought the same thing. In your example, 20ma and 2.2V forward voltage would require a 140 ohm resistor in a 5V TTL system. That's why the LEDs are so dim with those 470 ohm packs.
Then again, LEDs have become so efficient, one could run regular LEDs at (5V - 2.2 V)/470 R = 6 mA and they'd still do a perfectly good job as indicators. Thanks for reminding me! Great channel, great conversations!
squalazzo The component itself is called a "bussed resistor network". Bussed means that one end of all the resistors is attached together, compared to "isolated" where all the terminals are kept separate. The particular package that Julien's component is in is called SIP, Single Inline Package.
No it's an adhesive putty substance and normally used to fasten paper or posters to the walls without making any holes or leaving any marks when it is removed. en.wikipedia.org/wiki/Blu-Tack
No, it really wouldn't be difficult. (I use marker pen once I've determined A&K.) These LED arrays sometimes have a corner chamfered like an IC pin 1 marker. The chamfered corner indicates one corner has been chamfered.
well no .... but blindly guessing is not smart when you have the datasheet ^^ .... I marked mine with a dot after testing it with a multimeter in diode testing mode.
Although the voltage would remain constant for the LED pack, the current changes depending on how many LED's you have turned on. To calculate the resistor value, you use voltage drop (5 volts minus the forward voltage of the LED) divided by current. So for one LED, it would be one resistor value and then a different resistor value when two LEDs are on, and so forth.
In his previous postbag video, Julian explained that he wants these rather than the round LED's because they are a better fit to the breadboard, and because they also look neater.
NoName You want him to sink current on his IC but he wants his leds be on for a high state output on his IC. It means he would have to use a inverter IC, which clearly isn't worth it.
It's not what I want, it is convention. Can run into problems breaking established convention. Like brightness problems, like data corruption problems, or chip failing.
Other than actually making all the components 'yourself,' isn't the whole thing *bespoke?* I guess that I will be alright if you don't *PRE-drill* any holes or make any *artisinal* food.
You could've put common pin on the other row of pins. That way you would have the common fitting into the power lines directly (maybe with some little bending) without having to use that link on the side of the chip.
Why don't use middle 8 LED-s leaving most left and most right ones unused, it will be symmetric and aesthetically more elegant.
I agree - it's also much easier to read the binary value if it's centred in the display :)
Tie both outside pins to the 'common' and leave them straight until you install it on the board, then just fold- under/trim off the undesired pin.
@Kew Akl: Good idea!
Great idea Kew.
Huh, I would say that makes it harder to read....
*Quality Street* ™ is a good source of small coloured filter gels.
And chocolate.
Funny there is not a lot of info out there on using SIL's. I have been building devices that use 8-10 LED's and using a LOT of resistors, where one or two SIL's would work. With that in mind I purchased a variety box of SIL's from the Electronic Goldmine online. It arrived with over 100 SIL's now the problem is figuring out what each one is in value. They have all sorts of markings due to various makers and designs, I think I have sort of figured out most of them now, it looks like it should
If you increase the led current a lot, you'll probably have problems with voltage dropping. Memory chips or logic chips can supply a very limited current. This creates problems with other chips not getting correct levels due to excessive current draw. Actually I'm supprised that it works even currently!
To be safe, you'd better use a buffer to isolate leds from the logic level bus.
All it takes is a ULN2804 if you are just hanging a 20mA load off the end.
Being a couple of jumps ahead here, wanting the create my own 8bit breadboard computer, based on the videos from Ben Eater et al. and wanting to show the the address and databus inputs you are currently prototyping, I came across the same scenario with these 10bit bar graphs: I tested a number of SIL resistor networks and found the best turned out to be 330R
for both 3.3v and 5v. I know you said you'd try the 330R SIL and I think you'll find it's the best option for a good brightness level.
Andy Jary , sweet :) That's one of two values I ordered & am waiting for.
Blue LEDs put out hundreds (thousands?) of times more photons than red LEDs for the same current. Using higher value resistors for the red and lower for the blue will increase the difference. I use resistors on the Blue LEDs that are 10 times the value of the red ones, and they're still noticeably brighter (but much less distracting).
The parameter of the side at which the common ground pin sits is the same parameter as the side to which the pins hang, as you can simply rotate the board for the pins to hang to the other side, with the only difference being that the common ground ends up at the right side instead of left (or the other way round)
Great. I love when you improvise a new component. That's 10 McGayver points to you. :-) Please do more audio projects.
Not sure if your Icon is a pipe, or a side view of a beard!
Spikey DaPikey it's a pipe
No it isn't...;)
You should try making a DIL package yourself, by getting those square LEDs(i forget the name) and attaching all the elctronics, aligning it inside the casing and pouring on resin. That would be interesting!
Emil Carr , they're often listed as 257 LEDs. (Because they're 2x5x7mm)
234s are common too.
Also cheap, about €$1.50 for 100 of any colour.
Sounds ideal! I want to see it done
The more current you draw from those pins the more issues you are gonna have. Best off using a high value resistor so LED just lights up. Unfortunately this is rather camera unfriendly. Maybe other adjustments can be made but as you multiply the setup there gonna be trigger and voltage issues later. Like video, like the bar graph idea.
What if you started one pin over so it would have been centred?
but Julian , isnt it better to sink, rather than source current for the bar displays? will you not get random bit toggles because of current draw?
It seems to work OK on the TTL outputs. On CMOS outputs there's no issue because they're complementary.
Julian, According to the data sheets 74LS gates and counters can sink a maximum current of 8mA (16ma for some) but maximum source current is only 400uA so sourcing current to the LEDs is very bad design practice. Saying "It seems to work OK" is promoting bad practice.
My experience is that blue LEDs are brighter at the same current as red LEDs. That means they need a higher resistor for the same brightness.
Robert Eliassen , My PICkit3 has a blue LED on it, covered with 4 layers of PVC tape to make it less eye meltingly blindy.
I wouldn't use red at all, since it is harder to see somehow and red LEDs never get so bright.
Nice project Julian!
Two things:
1) You do know bar with upper pins and common left IS the same as a bar with lower pins and common right? ;) Aka, only two types
2) Blue leds indeed have a higher drop thus need a lower resistance for the same amount of current. BUT, blue leds tend to be a lot brighter with the same amount of current then the normal red leds... So 13mA (150Ohms) for the blue ones just makes them reaaaallllyyy bright and swamp the camera. The reds look just fine! Just use more like 2mA to 5mA for the blues to match :)
Why don't you just colour in the unused LEDs with a black marker?
the extra leds might be useful for visualizing carry but if Julian gets around to building ALU. or maybe a Status register display which would have all of those extra bits (carry, zero, overflow, etc) but I'm now curious which architecture he's going for
I might have gone "old school" & put 2 wraps of wire wrap wire on the SIP common pin & the LED array lead it goes to; Gives the solder something to be attracted to + a good mechanical & electrical connection (compared to some other methods)
Hey Julian, can you please make a Fade-in Fade-out LED (Strip) Dimmer and sell the kit on your site or put an affiliate link so we can buy the parts? THANKS!!!
I noticed that the LED's on the right were considerably brighter then the ones on the left. Does that indicate the resistor pack has resistance across the common buss? Otherwise it should have the same amp draw across each LED no matter how many are lit. Especially considering it is tied directly to the negative terminal. I did not see the blue LED's changing in output so it is not a supply issue. Hmm
I think the brightness difference you are seeing is an artifact of the camera angle. If you watch the video before the red tape is placed over the LEDs there doesn't appear to be any difference.
absolutely fabulous
realy looking forward the this series.
Make them with a 20 pin IC socket, then you can apply the LED array later, in various colours & orientations.
Nice idea. If only IC sockets had nice long pins like these displays have. The pins on these displays are long enough that I can angle the displays forward a little which makes them easier to see.
Wire-wrap sockets have silly-long pins.
Nice solution to 8 LEDs in line.
I put blue LED warning lights in my car and had to use a massive resistor just so it wouldn't blind me at night.
Wouldn't a little nick or crease on the pin stop the solder wicking up past the point you want it to?
Szlater Szlater That might complicate or interfere with inserting it into the breadboard.
Maybe he could have inserted it into a bit of the blue tack.
Thomas Bland You're right, didn't think of that.
julian what's the brand of the solder you use ?
Next time, tin the SIP leads before you put the package between the pins of the display. Also, clip the 3 leads so they're not in the way when soldering up.
10 10 till we do it again!
Colour in the unused leds with a sharpie
Julian. Thanks for the time.
Julian, guessing from your R value, do you really want to run the computer on 12 V (20 mA, 470 Ohms, +2.2 Vf)?
I thought the same thing. In your example, 20ma and 2.2V forward voltage would require a 140 ohm resistor in a 5V TTL system. That's why the LEDs are so dim with those 470 ohm packs.
Then again, LEDs have become so efficient, one could run regular LEDs at (5V - 2.2 V)/470 R = 6 mA and they'd still do a perfectly good job as indicators. Thanks for reminding me! Great channel, great conversations!
lot of investment is going on for discrete computer. hopefully this series will continue for sometime.
It's my favourite project at the moment :)
Julian Ilett mine too
and mine and I don't understand most of it ; -)
what's the actual name of those "rail" or "line" resistors? thanks
squalazzo
Hi, they are called resistor networks or sometimes SIP (Single in line package) Resistors.
squalazzo The component itself is called a "bussed resistor network". Bussed means that one end of all the resistors is attached together, compared to "isolated" where all the terminals are kept separate. The particular package that Julien's component is in is called SIP, Single Inline Package.
Jules just buy some 8 LED ones already :D I posted a link on your facebook page lol :P
is blue tack just playdough?
No it's an adhesive putty substance and normally used to fasten paper or posters to the walls without making any holes or leaving any marks when it is removed. en.wikipedia.org/wiki/Blu-Tack
No. Blue-tack is the stuff you use to put posters up on the walls etc. Play-Doh is what kids play with.
would it be that hard for the manufacturers to put anode and or cathode onto the product
No, it really wouldn't be difficult. (I use marker pen once I've determined A&K.)
These LED arrays sometimes have a corner chamfered like an IC pin 1 marker.
The chamfered corner indicates one corner has been chamfered.
well no .... but blindly guessing is not smart when you have the datasheet ^^ .... I marked mine with a dot after testing it with a multimeter in diode testing mode.
But then you have to remember what the chamfer means. (Although not too bad if you think 'schematic' :) )
"The chamfered corner indicates one corner has been chamfered", excellent message from the Department of Redundant Redundancy :)
SuperCreff , yes, we took over from the now-obsolete Ministry of Obsolescence.
Really interesting.Thanks.
10 - 10 till we do it again.
Julian you most of the time give us the web sites were you buy stuff
He has done, in the postbag video from the previous day.
Can you make your mind up anode or cathode
Why don't you use just one for example 1W resistor?
easier to manifacture and you could use all 10 LEDs
Although the voltage would remain constant for the LED pack, the current changes depending on how many LED's you have turned on. To calculate the resistor value, you use voltage drop (5 volts minus the forward voltage of the LED) divided by current. So for one LED, it would be one resistor value and then a different resistor value when two LEDs are on, and so forth.
cengland0 Thank you for your answer
i calculated it for myself and you are right
i missed this point
PS Elektroniker , you'd get the same problem with 7 segment LEDs.
1 would be brighter than 8,
4 & 7 middle bright.
... you could just do the same with normal round LEDs a busbar and some resistors soldered on you know julien
In his previous postbag video, Julian explained that he wants these rather than the round LED's because they are a better fit to the breadboard, and because they also look neater.
Better to have the IC sink the current rather than source it.
1:30
WTF has your post got to do with my point?
NoName You want him to sink current on his IC but he wants his leds be on for a high state output on his IC. It means he would have to use a inverter IC, which clearly isn't worth it.
It's not what I want, it is convention.
Can run into problems breaking established convention.
Like brightness problems, like data corruption problems, or chip failing.
RED LEDs aren't really bright. I would have used just all blue...
Kyôdai Ken , different colours for address and data.
You should improve your video editing. That will us time and your channel will grow drastically,because your content is good but time consuming.
101010 is the answer.
Other than actually making all the components 'yourself,' isn't the whole thing *bespoke?*
I guess that I will be alright if you don't *PRE-drill* any holes or make any *artisinal* food.