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A way to turn on/off the 5v output on a panda?


#1

Hi,

I need to supply 5v to a relay in order turn it on.
But IO’s provide 3.3v right?

Is there a way I can turn on/off the 5v on output on the panda?
Or is there another way I can solve this problem, without having to add extra components?


#2

I would absolutely not recommend you to drive a relay directly from your fez pin.
The proper way would be to do it like this:

Do NOT forget the diode placed over the relay contacts.
It’s there to protect your other electronics (including panda)


#3

I’ll check that link
In the mean time I found that we have 3v triggered relays as well,
I should still not conect these directly?


#4

No, you won’t


#5

So,
meanwhile I found solid state relays that are switched using something between 3v and 32v.
And that seems to be working.

But I’m really not an electronic kind of person, so I don’t really know what I’m doing :stuck_out_tongue:
I’m not supposed to just connect the pins from my panda to the relay (even though that works)

Can someone tell me why that is?

I should also note, it’s a solid state relay.

ANV SSR -40DA


#6

Even with a solid state relay you should use the diode described before for inducting loads.

And if you do not know what you are doing, you should do some research :stuck_out_tongue:


#7

Relays are notorious for back-current, which is why you put a diode over the terminals. When the circuit “breaks”, the back-current can zap your uC or whatever is controlling it if oyu don’t use a diode.