nigelsheffield wrote:So are all the arduino pro mini without xtal likely to work at lower voltages?
Just so I know for future purchases, for sensors then the xtal version might be fine as its not critical for flying but s.bus decoder the resonator type would be safest bet?
That doesn't depend only on the regulator. It depends also on the ability of the processor to work at 16Mhz with a lower voltage.
If its the regulator that's the problem then I guess it could be powered direct to VCC with a nice stable 5v but no more.
If you have a good BEC it shouldn't be a problem. There are a couple possibilities.
- You can for example the arduino from the S-Bus power and power the servos from another power supply.
- You could power the arduino from the first 2 cells the main battery using the "Raw" input. The arduino doesn't take much current and wouldn't unbalance your Lipo.. You could then power the servos the normal way. Just connect ground and signal to both S-Bus, and servo (PWM) lines.
- You could do it the way you said, with a regulator. But better to use for example a 8V regulator to the "Raw" voltage input of the arduino, instead of a 5V reg.. The reason is that the greater the voltage drop across the regulator, the greater is the waste of energy through heat.
So, you really have some options. My favorite is the second I guess, connecting to the first 2 cells of the lipo. I will give it a try when I build my next oXs sensor. At the moment I have a regulator, or use the arduino regulator directly to a 3s Lipo.. But it does get quite hot because the big voltage drop..