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Currently I am building a quadcopter with Raspberry Pi and I have four 20A Tunigy Electronic Speed Controller (ESC). I was wondering about could I use ESC's red wire to power my Raspberry-Pi? (tying 4 red wire out of ESC could fill the current requirement?).

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    \$\begingroup\$ Can you provide the ESC part number or a link to the product page? That would help. \$\endgroup\$ – Ricardo Aug 7 '14 at 21:36
  • \$\begingroup\$ hobbyking.com/hobbyking/store/… \$\endgroup\$ – Arjun Aug 7 '14 at 21:40
  • \$\begingroup\$ I've edited your question to include the link. Thanks! \$\endgroup\$ – Ricardo Aug 7 '14 at 21:42
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It seems that you should be very careful using the BEC (Battery Eliminator Circuit) on your ESC. The hobbyking link says it outputs 5.5V while here it seems that the raspberry is very very picky at input voltages.

In my opinion 5.5V would be no harm at all but the specs were written by an engineer and it's better to trust them (on average). You can either search for better specs (these FAQs are not a specification) hoping for the best, try your luck hooking the BEC and the raspi together or search for a LDO regulator such as this, that seems to be in the 450mV range of dropout voltage sourcing 1A@5V. Keep in mind that 500mV is a very, very low headroom to put a regulator in between, but searching makes miracles sometimes.

I'd go for the last option, you want a nice 'n stable supply for the raspi anyway, and with 1$ you get the regulator and the necessary capacitors.

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  • \$\begingroup\$ Thanks for your response Vladimir. I will definately try this. As I am new to all these RC things, I am curious on one more Topic. For normal start-up of ESC I need to provide minimum of signal and then turn on the ESC right? So if i choose to power my Raspberry-Pi through ESC's BEC, how would I be able to give signal when ESC are not turned on? \$\endgroup\$ – Arjun Aug 7 '14 at 22:29
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    \$\begingroup\$ The BEC will turn on when you connect the battery, so the raspi will be powered anyway. The ESC will see a bad input, and if it's nice it won't start, if it's bad it will start doing random things. Anyway this should not happen since hooking ESCs to a raspi is dangerous because linux is NOT a real time system and bad, bad things can happen. A propeller can cut away a finger, that's not something you want to experiment with. \$\endgroup\$ – Vladimir Cravero Aug 7 '14 at 22:34
  • \$\begingroup\$ If I am using other flight controllers like Arduino even then I can't turn on ESCs and Arduino simultaneously, can I? What happens if ESCs are turned on without Signal? \$\endgroup\$ – Arjun Aug 7 '14 at 22:43
  • \$\begingroup\$ Arduino is better since it is a microcontroller, and the right software might be just fine. Have a look here. About your second question, that depends on the ESC. That's something I would avoid at all costs. \$\endgroup\$ – Vladimir Cravero Aug 7 '14 at 23:01

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