Yes, this right here.Not really. You basically have two wires coming out of the battery pack slide-on connector. Conventionally they will be red for positive, and black for negative. One way to proceed is to splice two red wires into the single red wire, and connect these two wires to their own fuse holder (I recommend automobile fuse holders). Then the two wires on the other side of the fuse holders will feed the two buck regulators (positive input terminal). You'll have to splice two black wires to connect to the negative terminal of the buck regulators too. This is your ground reference.Thanks for the breakdown of how to implement. I am new to the hardware side of things so have some to learn here. Is there an existing example you can point to of stacking the fuse with buck converter? If not no worries I will dig around
Right.
You already said that you didn't want separate supplies, but you probably should. Not least because if your servos draw too much current then the Pi will brown out.
I was also going to suggest the power tool battery approach. You'll have to be a little bit careful as they can deliver a very large current if you make a mistake. You also have to keep an eye on the voltage as not all battery packs have built-in low-voltage cutout (although if they do, you'll have to be careful that power is not abruptly cut and make your Pi sad).
I'd suggest you look at your local DIY store for cheap own-brand battery packs and charger just for this application. Acquire or make an adapter to break out the power connection. Add a fuse. Add a buck converter to provide 5V to the Pi. You won't need 5A, but you can if you want. Add a second buck converter (and maybe second fuse) to power the servos. 5V is fine, but some are rated at 6V. Your servo control signal ought to work as there will be a common ground due to the buck converters sharing the same battery supply.
Now you have two buck regulators being fed from the battery pack. If they are fixed voltage (5V) then you're all set. If they are adjustable, connect the battery pack and adjust each one. 5V for the Pi, 5 or 6V for the servos (or whatever).
The buck converters have two output pins, positive and negative (ground). You can connect the 5V Pi supply to the 5V and GND pins in the Pi GPIO connector, or wire up a USB-C plug and plug it in. You can connect the servos to the other regulator, but again you'll have to splice cables together somehow to feed more than one servo.
Finally, connect your GPIO pin of choice to the servo control pin and send your servo control signal.
I'm not sure how easy it is to generate servo control signals on Pi 5. It's easy on earlier models, but the GPIO architecture changed on Pi 5.
You end up with just 1 supply just one buck converter for each voltage level needed in your project. Just remember to tie your grounds together like already mentioned.
This also gives you the ability to use a usb-c pigtail for powering the pi or powering the pi via the gpio pins. Either would work, whatever is easier for you.
And one more thing: cheap buck converters are cheap for very good reasons. Most of them aren't actually rated for the power they're advertised or don't have enough heat sinking abilities. So don't just go with the cheapest ones you find AND choose ones that are rated above your specs for a bit of wiggle room too.
Statistics: Posted by memjr — Thu Jan 09, 2025 9:16 pm