> On Aug 24, 2016, at 7:24 PM, Przemek Klosowski <[email protected]> > wrote: > > > > On Tue, Aug 23, 2016 at 5:18 AM, <[email protected] <mailto:[email protected]>> > wrote: > > When I got my new bbgw I ran an internet search to find how to use the relay > and did not find an easy answer, so here goes: > 1. The Grove - SPDT Relay(30A) - uses +5V , so you need to solder the third > pin of that groove connector. Disconnect it from the board, and connect it to > the input 5v power. > > It seems that your relay requires nominal 5V coil voltage and 185mA coil > current. This is far beyond what a BBB pin can provide: they put out 3.3V and > barely above 10mA. Additionally, switching the coil on and off generates > inductive spikes that are likely to damage the BBB output circuits. You need > some sort of coil driver; I suggest buying something, e.g one of > http://blog.machinekit.io/p/hardware-capes.html > <http://blog.machinekit.io/p/hardware-capes.html>, or building your own > circuit like this one http://i.stack.imgur.com/OhY9d.png > <http://i.stack.imgur.com/OhY9d.png> This image is incomplete. You still need a diode across the relay coil or the transistor collector will see a much higher potential than the supply rail.
Regards, John > > -- > For more options, visit http://beagleboard.org/discuss > <http://beagleboard.org/discuss> > --- > You received this message because you are subscribed to the Google Groups > "BeagleBoard" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected] > <mailto:[email protected]>. > To view this discussion on the web visit > https://groups.google.com/d/msgid/beagleboard/CAC%3D1GgFMYszu7ETm7KWi6UvcvzRZFXE5Z2dsy3Bt2wf2tB2ROA%40mail.gmail.com > > <https://groups.google.com/d/msgid/beagleboard/CAC%3D1GgFMYszu7ETm7KWi6UvcvzRZFXE5Z2dsy3Bt2wf2tB2ROA%40mail.gmail.com?utm_medium=email&utm_source=footer>. > For more options, visit https://groups.google.com/d/optout > <https://groups.google.com/d/optout>. -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/DEBF839D-5F3C-4765-A6F8-A5E9A208C7E3%40gmail.com. For more options, visit https://groups.google.com/d/optout.
