Using icsp as another 5v connection

Official Hardware Classic UNO R3
1

hello, can i use the vcc of the iscp section to power another device like e.g. a servo?

dont judge if the question is stupid pls

2

Which Arduino board or device, generally?
You can. It is directly connected to 5V so no problem. However, servo is probably (almost certainly) too much load. Total power consumption may not exceed the limit for specific device. Check the specification of your board.

3

No. Power servos externally.

Don't tell me what to judge, or not.

2 Likes
4

The general rule is that the board (UNO and others) is NOT a power supply. Each board has a limit, the UNO is 20 mA, so A temp or humidity sensor is ok, but NO motors like a servo. Many newer boards are a lot less.

5

20 ma rating applies to each digital output.

The 5V pins, whether on the ICSP header or on the board edge, are less well defined.

But certainly, a servo is beyond any reasonable expectation, not even the 9G servos. Use a separate 5V supply for that, and do not forget to create a connection from Arduino GND to the negative side of that servo supply.

6

thank you! i have bought a breadboard so the motor and the signal transmitter can share the 5v normally, is that doable?

7

Without a schematic I will probably say no. I am assuming the 5V is from the regulator on the Arduino. Hopefully the following helps you:
Gil's Crispy Critter Rules for Processor Hardware:

  1. Rule #1: An Arduino is NOT a Power Supply!
  2. Rule #2: Never connect anything inductive (motors, speakers) directly to an Arduino!
  3. Rule #3: Avoid connecting or disconnecting wires while the power is on.
  4. Rule #4: Do not apply power to any pin unless you are certain of what you're doing.
  5. Rule #5: Do not exceed the maximum voltage ratings.
  6. Rule #6: Many Arduinos cannot power transmitters directly.
  7. Rule #7: Before powering your project, take a break and double-check the wiring.

LaryD’s Corollaries:

  1. Coro #1: When starting out, add a 220Ω resistor in series with both input and output pins to protect against shorts.
  2. Coro #2: Invest in a Digital Multi-Meter (DMM) to measure voltages, currents, and resistance.

Note: Violating these rules can turn your Arduinos into crispy critters. For optimal performance, keep your wires under 25 cm (10 inches).

Additional Tips:

  • The L293 motor driver, though common, is inefficient as it can lose around 3V as heat when driving both legs of a motor. Consider using a motor driver with MOSFET outputs to reduce heat loss and conserve battery power.
  • For more on powering Arduino boards, explore this guide: Powering Alternatives for Arduino Boards.
8

Not sure what you mean by 'signal transmitter', but remember if a servo or any motor shares a power line with a noise-sensitive device like a radio of some sort, you need to add properly sized capacitors and a diode to suppress the noise. Search the forum for noise suppression.

9

The only stupid question is the one that was never asked.

Yes the 5V pin on the ISP is 5v, the same connection as Vcc. However it is limited in current capability, especially if you are powering it from Vraw.

10

Show exactly how you have them connected.
It may or may not be doable.