Electrically triggered physical switch

General
1

Hi,

I need a physical switch (like a breaker) that is able to to be tripped by a signal sent from a microcontroller like the electron.

I need to be able to send a signal to the switch from the controller which will cause the switch turn off and does not turn back on until it is physically reset by some kind of carbon based life form (like a human).

Any suggestions would be greatly appreciated.

Thanks,
smd75jr

2

Ground fault interrupt device could do it, although it may be a bit more than you were looking for.
Once the loop detects more than the rated limit(0-100mA usually) difference in the coil it will trip and needs human intervention to reset.

If the Electron does not need to stay powered after it turns off, you could use an intelligent switch with button, and power the electron from the output also.

3

Hi @smd75jr

I would do some research on E-stop relays or safety relays. These are designed for situations like this, especially for dangerous machinery.

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4

Bloody hell, of course, feeling a little dumb because I’ve worked with those before. :laughing:

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5

You could also use a latching circuit on a dpdt relay using 1 pole Common and Normally Open and a manual switch to keep the relay powered when tripped. (a power loss/failure will also reset this)

6

(Sorry for the delayed response, been bussy with school work)

I considered this, but I don't think it would work in my application as it will be running on battery power for very long periods of time (anywhere from a few weeks to over a month on a single charge). A relay consumes quite a bit of power (a quick search for 3v relays shows anywhere from 100mA to over 600mA) so it is not terribly practical.

7

I’m sure there are other options. How much current is running through the relay contacts, and is it AC or DC, and volts?

8

5VDC at 3A max.

9

Oh that’s not much. If you can switch the negative side, an N-channel MOSFET would do, and consumes very little power. It needs a Vgs of 3.3V or less, which is a bit harder to find. Or a TIP120 but it won’t give you a full 5V as it’s a Darlington transistor. Otherwise for positive switching, you need a P-channel, with an NPN to switch it.

Edit: Actually you can switch a P-channel with just the 3.3V I/O (5V tolerant) pin by using a 10K resistor to pull it up to 5V while the I/O pin is in input mode (with no pullup/pulldown) and change to output and low to turn it on. I’ve done it a few times to save space and it works great.

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