J
Jeff Dege
- Jan 1, 1970
- 0
I've been working on a project that involves switching some relays with a
Basic Stamp microcontroller, with the idea that the relays would be wired
into my house's doorbell circuits. For the microcontroller to close
relay1 would be the same as pushing the front doorbell, to close relay2
would be the same as pushing the back.
Everything works fine. The microcontroller's output pins drive a couple
of switching transistors, which sink the relay coils.
Except that when I actually connect the relays to the doorbell circuits,
when the microcontroller closes the relay, it immediately resets.
This doesn't happen when the relay is connected to nothing, or when it's
connected to LEDs or lightbulbs, so I'm pretty sure it's a matter of
needing to add some filtering caps.
I've had similar problems, driving small electric motors, and I just stuck
whatever capacitors I had lying around whereever they would fit.
I'm hoping that someone can give me some more precise ideas as to what
type and size of capacitors to use, and where exactly they should be
placed.
Basic Stamp microcontroller, with the idea that the relays would be wired
into my house's doorbell circuits. For the microcontroller to close
relay1 would be the same as pushing the front doorbell, to close relay2
would be the same as pushing the back.
Everything works fine. The microcontroller's output pins drive a couple
of switching transistors, which sink the relay coils.
Except that when I actually connect the relays to the doorbell circuits,
when the microcontroller closes the relay, it immediately resets.
This doesn't happen when the relay is connected to nothing, or when it's
connected to LEDs or lightbulbs, so I'm pretty sure it's a matter of
needing to add some filtering caps.
I've had similar problems, driving small electric motors, and I just stuck
whatever capacitors I had lying around whereever they would fit.
I'm hoping that someone can give me some more precise ideas as to what
type and size of capacitors to use, and where exactly they should be
placed.