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javeryh's Woodgrain Cabaret Copy
javeryh:
--- Quote from: PL1 on December 23, 2020, 06:45:47 pm ---
--- Quote from: javeryh on December 23, 2020, 04:21:20 pm ---can I wire these two LEDs in parallel? So I'd only need one resistor.
--- End quote ---
That configuration makes it a series-parallel circuit instead of two parallel circuits.
A guy on Stackexchange asked about a setup using one resistor to feed parallel LEDs.
https://electronics.stackexchange.com/questions/164370/9x-1w-leds-parallel-series-resistor-calculation-help-needed
--- Quote ---Manufacturing tolerances might make one LED draw a wide range of currents for a fixed voltage applied to its terminals. If you applied another LED in parallel one LED might take virtually all the current whilst the 2nd LED took virtually zero - this is the problem of not using a seperate resistor for each string of LEDs.
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Best practice is to use one resistor per parallel branch so you get consistant current which will give you consistant brightness.
You can either wire it like below or daisy-chain one 5v line to the left side of the two resistors the same way you daisy-chain ground to the right side of the LEDs.
Scott
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OK got it. I'm just trying to figure out how to do this in the most practical way - connecting to the pin on the iPAC2 is kind of a pain. Seems like my original pic is best but if I'm understanding you correctly, I could also do it like this as well?
The extra resistor is no big deal - they are so tiny though! I have some shrink tube and solder that will hopefully hold it all together (and not melt).
The wire I'm using that I posted above is VERY thin once I cut it open (only 2 wires too - Red, which is going to 5V and white, which is going to GND). There was also strands of wire in between the white and red covered wires, which I assume is what is used to connect X1 and X2 but it seemed weird to me.
Zebidee:
I find that wiring diagram confusing, so I re-created it for you (below). I like to keep my 5v and GND together so you can think of it as a "rail".
recycling old cables is always a bit of a mystery tour. Sometimes it is great, sometimes not so great.
To make things easy for yourself, you could try getting some "arduino wires" for this kind of thing. They come in different colours with male/female ends already attached. They can be easily separated from the "ribbons" of wires. Great for 5v project applications. Like these:
https://www.aliexpress.com/item/1005001769657025.html?spm=a2g0o.productlist.0.0.7f14377fbVavbk&algo_pvid=8076956e-0a85-4fb8-b71c-bd36cc26a824&algo_expid=8076956e-0a85-4fb8-b71c-bd36cc26a824-5&btsid=0b0a555c16087706106626359eba49&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_
PL1:
--- Quote from: javeryh on December 23, 2020, 07:21:54 pm ---OK got it. I'm just trying to figure out how to do this in the most practical way - connecting to the pin on the iPAC2 is kind of a pain. Seems like my original pic is best but if I'm understanding you correctly, I could also do it like this as well?
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Yes.
One easy way to connect the 5v line to two resistors is to strip and tin the wire, bend a hook in the wire end, then bend hooks in the leads of two resistors and solder all three hooks together in a Y-shape -- like this, but with two resistors instead of one.
Then you can solder a wire to the other end of each resistor and add a 0.110" QD for the LED+ tab.
--- Quote from: javeryh on December 23, 2020, 07:21:54 pm ---The wire I'm using that I posted above is VERY thin once I cut it open (only 2 wires too - Red, which is going to 5V and white, which is going to GND). There was also strands of wire in between the white and red covered wires, which I assume is what is used to connect X1 and X2 but it seemed weird to me.
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That might be a shielded audio cable for a CD or DVD drive. :dunno
Dupont jumpers like the ones Zebidee linked to are very handy and easy to work with.
- Use a F-F jumper.
- Pull the housing off one end.
- Push the resistor lead thru the pin (see attached pic), bend the lead so there's a good mechanical connection between the lead and pin, then solder the lead to the pin.
Since the jumpers are cheap and plantiful, it might be easier to run four separate lines instead of daisy-chaining the 5v lines and daisy-chaining the grounds.
Scott
Zebidee:
The Dupont jumpers should fit snugly onto those IPAC pins. You could cut a double-female and solder the bared wire at each end, but...
I like Scott's way better (two pairs of 5v + GND lines) because stronger connection and you can different colours for the 5v lead to each LED. So long as you have the extra 5v connections on your IPAC. Otherwise daisychaining is fine too.
It is all the same parallel circuit we've shown you in various forms as the 5v rail will be connected at the IPAC anyway.
javeryh:
Alright... wiring is complete and... nothing. LEDs not lighting up. Not sure what I did wrong but here's a quick video walking through it.
Any help at this point would be appreciated... I literally have no idea what to try next to turn these LEDs on.
I made 2 separate runs from the two 5V pins on the iPAC2 to what I think is + on the volcano button with the 220 ohm resistor soldered in-line for each wire. Then I daisy chained the ground wires and ran that back to GND on the iPAC2. I plugged the iPAC2 in and the green light came on so it has power but the LEDs did not light up as expected. Do I need to tell the iPAC2 to provide power to those pins in software or something?
Thanks guys. :cheers: