What relay for the BBB when controlling about 5V battery-circuit?


I want to control a 5V battery-powered circuit through a relay.

I am quite unsure which will work with the BeagleBoneBlack and a simple GPIO input.

Are there any recommendations?


Hi! It just so happens that my IEEE group here at BYU-Idaho are putting together a flight computer for a rocket and used this to deploy our recovery system:


I can upload a schematic later but the idea is to have a 9V battery power the transistor which is triggered from an I/O pin from the BBB. This battery also supplies the current to switch the relay after the I/O pin is triggered. If your current draw is low enough, a transistor would work, but the BBB GPI/O pins output 3.3 V or you could use a 5V output pin that the board supplies to get the 5V directly.

I’m not completely sure what you are asking. Are you wondering if the 3.3V from the Black is enough to switch the transistor?


solved the problem by using following circuit: http://electronics.stackexchange.com/questions/56093/how-to-use-a-3v-output-to-control-a-5v-relay (the second one - first did not work…)

I used a 500 Ohm resistence.

I’m glad it works, but the second circuit uses a BJT not a N-Channel MOSFET. If you are using the relay board from the ebay link it already comes with the N-Channel MOSFET you need for switching the relay with a 5V source. So I’m confused as to why you would use a BJT circuit. Just wondering?

Yes, the second circuit uses a BJT (forgot to mention). I tried the first one but did not come to success.

The N-MOSFET I used required a lot of power to get working and there where no alternatives available (do not want to buy this stuff online and wait a week).

Ok, good. I was under the impression you already had the relay board from the link.
Good luck with your project.