I'm ramping up my prototype from a breadboard to a perfboard. My project basically consists of 10 strips of leds, 35 leds each. My code dictates that each strip performs the same function so they are set up as separate strips rather than in series.
This mean 10 data lines, 10 power wires and 10 ground wires. My question is, what's the best way to sort the power and ground wires? At the moment, I've got ground buses from Adafruit but I'd like to consolidate these onto the perf board if possible. The simplest way I can think of it would be to have 10 wires coming from 10 separate holes on the perfboard and then soldering each of them to a 10 gauge cable and then heat shrink everything?
I'll be dealing with a rough maximum of 25 amps, based on 350 leds at 60ma max per led.
Any suggestions for this? I'm new to electronics but I assume it would be a terrible idea to solder each of the power and ground connectors to a common line of holes on the perf board. I assume this would bottleneck the power and ground and 21 amps would not be able to reach the leds. The connections would have to be separate until they reach something that can handle this many amps, hence the 10 gauge wire?
How are the strips of LEDs connected? Strings of 3 LEDs & current limit resistor all sharing the same current to turn them on? Maybe your current draw is not as high as you think.
I'll try to explain this correctly. If you mean how are the LED strips connected to each other, they're not. I'm sure you understood that already but I thought I'd be thorough.
They are 10 separate strips of leds. On my current setup, I have 3 strips connected and each one has it's own independant data pin on the Arduino. Then the power and ground wires from the strips simply converge at the power supply.
I've got some Adafruit ground/power buses but I was thinking of taking the jump straight to the perfboard instead of soldering wires to all my strips etc.
I'm no expert as you know but I don't know how the current draw could be lower than the total number of leds multiplied by the potential draw of each led?
The simplest way I can think of it would be to have 10 wires coming from 10 separate holes on the perfboard and then soldering each of them to a 10 gauge cable and then heat shrink everything?
In more detail, for the wires, I was thinking of having the smaller wires attached to the board then connect them to an 'off board' larger wire. The other end of the bigger wire would then connect to the power supply so I wouldn't need it to be soldered to the perf board. Maybe for the sake of not tearing the smaller wires off the board, I could stick the larger wire to the board in some way but not solder the larger wire to the board.
So on the perfboard, there would never be that many amps on the board, just what's needed to be drawn by each strip.
Here's a diagram of my power distribution proposal:
So you can see that I've just shown the power here and you can see that there is no perfboard in sight. There could just be wires coming from the power and ground contacts on the led strips or a combination of shorter wires with some soldered routes on the perfboard. I need to have everything in front of me to decide the layout but either way, the current for each strip will be seperated until it comes 'off the board' and connects to the larger wire. So the highest current at any point on the board will be 2.1 Amps?
When I first started this thread, I thought there might be a popular perf board friendly bus bar that can be attached. So for example, I could route connections on the perf board to the bar and then attach a large gauge wire to one end. This would mean only 2 wires on the whole setup, power and ground. I could quite easily cut a piece of copper bar and connect it to the perfboard. I could drill a hole in one end, tap it for a screw and attach the 12 gauge wire.
So my question is, is my diagram suitable for power distribution? As in, is the large gauge wire it's own bus bar since there's no bottleneck?
You may be asking why I'm using a perfboard in the first place. I've been using an Uno plus a breadboard with loads of wires and some buttons which control the LED functions.
Now, I'm using a Nano which I'll attach to the board and I can get rid of the wires for the buttons and the data connections for the led strips. The only wires needed then would be for the power and ground.
This is electronics 101 I know but I'm a beginner as you said and feel I need to double check this stuff!
So the highest current at any point on the board will be 2.1 Amps?
That current is too high for perfboard. About 1A is the maximum.
There used to be thin tinplate bus bars to attach onto perfboard but I haven seen any for about 30 years now. What I do when I want a small run of high current is to solder up the strip and then reinforce it with a strip of 18 swg tinned copper wire on the back. In this respect strip board is better than perf board.
Really glad I asked now. This makes me think if the wire I've been using for my breadboard setup is too thin?
I bought this from SparkFun to tidy my setup a little:
I've only just realised it's 28 gauge but it seems to be dealing with the leds. I know it's not right though but the functions of my leds never use the full brightness. There's 3 functions, using 0,90,0 / 0,255,0 & 150,255,0 so I'm guessing the actual maximum would be nearer 40ma per led but I know this is still too high.
Your idea seems ideal. If we stick with Perf board for now, is it based on a single side board? Also, when you say reinforce it with a strip on the back, would each end of the copper come back through the board and connect to each end of the soldered strip?
I did a similar project recently. I just soldered the solid cores of mains wires (1,5mm^2) on the perfboard. Make sure all your solder joints are good. Cheaper soldering irons may not be able to properly deal with the thermal capacity and produce dry joints.
Also take some care about the screw terminals you use. I also send the 8A 12V side over the perf board, for that, I actually ordered parts from a reputable supplier, not Aliexpress as usual.
When you say you soldered the main wires on the perf board, is this with or without some sort of reinforcement as described above?
Also, what do you mean by screw terminals? Do you have a photo pf what you mean since I wasn't thinking of using them. Since I'm new to electronics, I'm not sure what the options are for this sort of thing so I'm all ears for different approaches.
With 12V 8A side, I mean the following:
You will supply the strip with 1 12V terminal, sending all the current over that one rail (in my case, 8A). Then, it splits into the three colors, so most of the ground side will consist of three rails, carrying only a third of the current, each.
With screw terminals, I mean something like these:
Is there a reason you need the LED power to go through the board? Since you mention data lines, I assume the actual power switch circuit is on the LED strip and the microcontroller just needs to apply a weak logic signal to turn the strip on.
If that's the case, I'd consider getting some 20A mains cable and wire nuts from a hardware store and daisy chain the power wires to the LED strips, and run a pair of smaller gauge wire from each LED strip to the microcontroller just for signalling.
Aren't you just making car taillights? Only reason to use perfboard is really just as support backing because you have some on hand and haven't cut anything else up. There is no reason to run anything at any point solely on perfboard trace. You'd do just as well to use scrap wood and drilling mounting holes in it.
Your LED strips are short, power going into one end each is sufficient. It's just a lot of soldering.
Thanks for the quick reply. This is making more sense now, you can see how new I am to this!
I was intending to simply use the perf board to sonsolidate the wires for the buttons to the arduino and the 10 data pins for the 10 strips of leds. Due to this, I suppose it's not entirely necessary for the 5V and ground contacts on the led strips to be connected in any way to the perf board but it would be a lot tidier.
I purchased this soldering iron, hopefully it's sufficient:
Here's a quick 3D model I made to show how I think I'm understanding this setup:
The connections are tricky to see so here it is without the perfboard:
I'm working on another simpler version too which will require a lit less soldering by using 3 way screw terminals very close to the start of each stirp.
A bit unnecessary but it'll work. Since this is an "assembled" piece, assuming you don't need to rearrange the strips again, I would just take a single sufficient gauge wire, and join all of the Vin pads of the strips together, and the same for the GND pads. Then a simple 2-wire screw terminal or jst connector or whatever 2-wire terminal you want to use. And it wouldn't hurt to do this from somewhere in the middle of the strips so you can hide all of your wiring behind the assembled piece instead of off to the side. But that depends on your end goal setup.
Yeah, I agree, totally unnecessary but It's my first time with perf board and I was thinking of exploring all aspects of it including options for power distribution etc but It would be easier to just connect the lower gauge wires directly to the pads as you said.
Are you suggesting daisy chaining the wires together instead of a seperate 5V and GND wire for each strip?
If so, what gauge wire would I need considering there'll be 21 amps? This is why I'm using 1 wire per strip, so the power is distributed to the higher gauge wire at the end?
14awg is the most you'll need, and yes just run along all the correct pads for power. Bunch of small wires (with even smaller conductors) don't change anything here other than giving you more work.
Practice soldering a bit before you try attaching wire to the traces on the strip. And just remember, a hotter iron for a shorter period of time is better than a cooler iron held to components longer.
