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Refer to this video for how to power it with the power supply
IMPORTANT: IT IS CRUCIAL YOU USE THE RIGHT VOLTAGE. Setting it to anything other than 5V will be bad and if you do that I will cry a little.
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Alternatively, you can power it with another 5V power supply, such as a battery connected to a 5V buck. If you do so, make sure the supply can provide enough current. When idle, the board uses <100mA but to be safe, I recommend using something that can supply something at least 200mA and if you can then 500mA would be nice to be even safer. If you are using servos, it will draw significantly more current. The worst case servo current that this board allows (this would be under load) is 1.5A per servo, so with a safety margin I recommend finding something that can supply 6+ amps.
Pinout
These are the important Seeeduino pins and what they are mapped to
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