Automation HAT Mini has 0.6v on outputs when closed with no supply

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1

Hi, I have an Automation HAT Mini that I am trying to use to control a ballast attached to some lights. When the output is high, the closed switch should cause the lights to turn off completely, but they are always very dimly on. I have found that even when the output is set to high IE completely closed, I still measure a 0.6v charge across the output and ground, and this is still true even if I completely disconnect the output from the power supply. I have tried using a resistor to pull the output to ground, but it still kept most of the voltage. Any ideas what I should do to help the system work the way I need? Is there something that I am misunderstanding?

Thank you.

2

I think you need to post more info on how its wired up? Where your switches are and what your using for power for the lights etc.

3

Hi thanks for responding.

The ballast has 10v leads that go to the switch. When the circuit is open, the leads have (about) 10 volts across them and the lights turn on. When the circuit is shorted, the leads should have 0V and that will cause the lights to turn off. But it is analog, so IE putting 5v on the leads will cause the lights to be halfway on, etc. My problem appears to be that the hat always has 0.6v on the output when it is closed, which causes the lights to be on dimly even when the circuit should be completely shorted. And those 0.6v seem to come from the hat/pi itself because they are there even when the supply is completely removed (but only when the output is set to high).

4

I’m guessing that’s the junction voltage of the mosfet or what ever is on the Automation mini. Can you use the relay instead?

5

Unfortunately the relay is mechanical and I was hoping to be able to use PWM to provide analog control. However, you have given me the idea to put the relay in parallel, which does seem to work to close the circuit completely. So I close the relay when the circuit should be closed and leave it open the rest of the time, which I guess means that my analog control has a bit of a step from almost closed to completely closed but I can live with that as long as the lights go out completely which they do. I think I’m happy enough with this solution for now.