I'm using a raspberry PI B+ to drive a relay via a BJT transistor. The GPIO pin source about 8ma ( calculated, since it is driving a 600 ohm load ) so when the I/O is on there should not be a too dramatic current difference. Relays are powered by another +5v rail. Both rails cames from a couple of 7805. After about 47 min ( yes, always the same time ) the device reboot. Any reason for that? Is there some way in having via software the voltage supplied? There could be any reason other than power fault causing a reboot? ( Temperature is, btw, about 55 C reported by software )

  • Are you powering a Pi from a 7805? If so I'd guess it is overheating and switching off. Why not use a switching power supply, you can buy a UBEC for a couple of GBP. – joan Jul 7 '15 at 7:51
  • yep they are part that already own. But strangely it seems to work if there is no gpio output, – Felice Pollano Jul 7 '15 at 8:32
  • The load on the gpios may be small but it might be the straw that broke the camel's back. I had a similar problem with a sonar ranger which worked fine until the system was busy and then started to produce wrong results. The drop of power available to the sonar ranger when the system was stressed was the problem (which I showed by connecting a more powerful power supply). – joan Jul 7 '15 at 9:10
  • @joan, yeah it could be... strange that the timing is almost perfect:) – Felice Pollano Jul 7 '15 at 9:55
  • That is certainly a valid counter argument, unless you can identify something which is launched at that time. However I'd certainly try an alternative power supply as soon as possible. – joan Jul 7 '15 at 10:03

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