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I'm building a robot that requires 12 servos and a Raspberry Pi. I will be using the Adafruit 16-channel servo shield(https://www.adafruit.com/product/1411) and a Raspberry Pi 3B. Of course, if they were both connected to the same power supply, it would be way easier to turn the system on and off.

Is there any way to do it, even with additional pieces or arrangements? If so, how?

Also, could the power supply be a battery? What characteristics should it have?

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  • \$\begingroup\$ This is not answerable without details of the components. Generally though, sharing power supplies would be a bad idea. Probably what you should do is use something like a 12v gel cell and get multiple switching power converters (perhaps RC hobby or drone "battery eliminators") to divide the load, ie, have one just for the pi, and another for every 3 or 4 servos. These modules would need to be of a type that can have a common ground on the input and output. Done right, an overload from a jammed servo would be limited by a current limit in that power converter, and not brown out the pi. \$\endgroup\$ Aug 23, 2020 at 17:43
  • \$\begingroup\$ I will be using 12 MG90 micro servos (which draw a couple hundred mA when moving) and either a Raspberry Pi or an Arduino UNO board, depending on the final code. All the components in the circuit work on 5V. My only issue is powering the servo board and the main board with the same power supply, and it would be great if the solution weren't very sturdy. Could I make it work with power converters and a battery? \$\endgroup\$ Aug 24, 2020 at 9:18
  • \$\begingroup\$ If you use separate power converters it can probably work; if you use the same one for the pi and servos you may see no end of trouble. \$\endgroup\$ Aug 24, 2020 at 12:08
  • \$\begingroup\$ So do you think I could connect two power converters to a single battery and then connect one to the raspberry/arduino board and the other to the servo shield and it would work? \$\endgroup\$ Aug 24, 2020 at 15:29
  • \$\begingroup\$ If the battery has sufficient power capacity compared to the load and is of sufficiently higher voltage that even with load droop it still meets the regulator minimum input... \$\endgroup\$ Aug 24, 2020 at 20:07

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Read the fine#§* manual RTFM

5v 10A switching power supply (http://adafru.it/658) (up to perhaps 16 servos).  V
4xAA Battery Holder (http://adafru.it/830) - 6v with Alkaline cells.     
4.8v with NiMH rechargeable cells, portable!    
4.8 or 6v Rechargeable RC battery packs from a hobby store.

https://cdn-learn.adafruit.com/downloads/pdf/adafruit-16-channel-pwm-slash-servo-shield.pdf?timestamp=1598199855

Each servo under max load draws 1A . Estimate your Ah or Wh needs and dont undersize it.

It you overvoltage with 2S3P Li Ion you must control acceleration not just position to avoid over heating servos but that might work. A battery balancer extends life.

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  • \$\begingroup\$ Thank you!!! It's a relatively small project, and all the battery balancers i'm finding are very big. I'm looking for power converters. Do you think I could connect two power converters to a 2S3P pack or similar and then connect each power converter to a board? \$\endgroup\$ Aug 24, 2020 at 15:51
  • \$\begingroup\$ It depends on the implementation. some chips no, some floating chargers yes. \$\endgroup\$ Aug 24, 2020 at 16:21
  • \$\begingroup\$ What do you mean by floating chargers? \$\endgroup\$ Aug 24, 2020 at 19:59
  • \$\begingroup\$ Not earth grounded output. lmgtfy.com/?q=What+do+you+mean+by+Floating+chargers&iie=1 \$\endgroup\$ Aug 24, 2020 at 20:43
  • \$\begingroup\$ While 4xNiCd is indeed what hobby servos were designed to run on back in the day, that's not going to run a Raspberry Pi or an Arduino. A 3v3 Arduino or (if alkalines are never used) an unregulated ATmega can work however. But something like a pi is going to need a switching converter, typically stepping down from a higher voltage. \$\endgroup\$ Aug 26, 2020 at 14:05

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