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javeryh's Woodgrain Cabaret Copy
Arroyo:
I believe that Javery is correct and these are 2V LED’s. At least the originals were. I discussed building a voltage divider for the ones I used on the flight stick in my thread to bring the 5V down to 2V:
http://forum.arcadecontrols.com/index.php/topic,156267.msg1644624.html#msg1644624
PL1:
--- Quote from: Arroyo on December 13, 2020, 11:28:41 pm ---I believe that Javery is correct and these are 2V LED’s. At least the originals were. I discussed building a voltage divider for the ones I used on the flight stick in my thread to bring the 5V down to 2V:
http://forum.arcadecontrols.com/index.php/topic,156267.msg1644624.html#msg1644624
--- End quote ---
The 220 ohm resistor acts like R1 and the LED acts like R2 in your voltage divider diagram.
How did I know that a 220 Ohm resistor would work for this application?
--- Quote from: yotsuya on June 10, 2015, 06:38:37 pm ---How I do it:
Wire in a 220 resistor on the line going to 5v. Crimp on a quick disconnect.
Attach the QD to the + end of the Atari button LED terminal.
Hook up the other end to ground.
Turn the machine on, see the red lit button.
No worries.
Never burned out a LED button with the resistor connected.
--- End quote ---
Scott
javeryh:
--- Quote from: PL1 on December 13, 2020, 11:19:48 pm ---What you need is a 220 Ohm (or 160 Ohm), 1/4 Watt (or 1/8 or 1/2 Watt -- smaller wattage ==> thinner leads) current limiting resistor between 5v and the LED+ terminal.
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--- Quote from: Arroyo on December 13, 2020, 11:28:41 pm ---I believe that Javery is correct and these are 2V LED’s. At least the originals were. I discussed building a voltage divider for the ones I used on the flight stick in my thread to bring the 5V down to 2V:
http://forum.arcadecontrols.com/index.php/topic,156267.msg1644624.html#msg1644624
--- End quote ---
Thanks guys. So if I buy THESE (100 LOL - I only need 2 max) I should be OK?
I would like to somehow pull the power from the iPAC2 - there are two trackball connections that I will not be using and there are pins labeled 5V. Could I use those for the LEDs?
I would run a wire from iPAC2 5V pin to the resistor and then the resistor to the positive side of the volcano button LED leads. I would run a separate wire from the negative side of the volcano button LED leads to the player 2 GND terminal on the iPAC2 (for ground). I realize this would mean as long as there is power to the iPAC2 the LED lights will be on. Would this work?
Also, which side of the resistor goes where? I assume it matters how it gets connected as it will be stepping down the voltage.
Sorry if this is ridiculously basic stuff... ;D
PL1:
--- Quote from: javeryh on December 15, 2020, 01:31:42 pm ---So if I buy THESE (100 LOL - I only need 2 max) I should be OK?
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They are a bit of overkill, but those will work fine.
Each LED and resistor pair are only going to draw a total of about 20 mA so that's 100mW -- around 60mW for the resistor and around 40 mW for the LED.
(Watts = V * A ==> W = 5v * 20mA ==> 100mW)
Same resistor in a 1/4 W size:
https://www.amazon.com/EDGELEC-Resistor-Tolerance-Multiple-Resistance/dp/B07QK9ZBVZ/
An assortment pack will cover many future projects as well:
https://www.amazon.com/McIgIcM-resistor-Electronics-resistors-assortment/dp/B06WRQS97C/
https://www.amazon.com/Resistors-Assortment-Tolerance-Excellently-Breadboards/dp/B07D2Z45CG/
--- Quote from: javeryh on December 15, 2020, 01:31:42 pm ---I would like to somehow pull the power from the iPAC2 - there are two trackball connections that I will not be using and there are pins labeled 5V. Could I use those for the LEDs?
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Yes. Those pins are designed to power the two LEDs of a trackball/spinner axis so they are perfect for this application.
--- Quote from: javeryh on December 15, 2020, 01:31:42 pm ---I would run a wire from iPAC2 5V pin to the resistor and then the resistor to the positive side of the volcano button LED leads. I would run a separate wire from the negative side of the volcano button LED leads to the player 2 GND terminal on the iPAC2 (for ground). I realize this would mean as long as there is power to the iPAC2 the LED lights will be on. Would this work?
--- End quote ---
Yes, you can either do it that way or you can connect one 5v line to the left side of both resistors in your diagram.
--- Quote from: javeryh on December 15, 2020, 01:31:42 pm ---Also, which side of the resistor goes where? I assume it matters how it gets connected as it will be stepping down the voltage.
--- End quote ---
There's no +/- polarity to a resistor so you can't install it backward. ;D
You may also want to use heat shrink like steps 1-3 here . . .
. . . and QDs like smalltownguy did here.
Scott
javeryh:
Scott - thank you for taking the time to provide such a detailed response. I just ordered the resistors and I'm looking forward to making this work! I have some shrink tubing so I will also try to make it as neat as possible. I should be able to finish the wiring this weekend. I'd love to have this playable but Christmas! :cheers: