Hall effect power switch

Other Hardware General Electronics
1

Hello all

I am using some hall effect switches to control a project. All fine there.

These output an Ov when the magnetic pen is tapped on them.

Does anyone have a circuit for a power switch using a magnetic sensor?

I have one of these sensors wired to power a TIP127 at the moment to apply power to the Arduino.
Then early in the code it outputs a high that then holds that transistor high. So powering on is fine.

But how to power off using the same sensor? I don't really want to add another sensor as an 'off', as I am trying to keep the component count low.

Also, with the A3144 sensor connected to the supply as the power on sensor, that is going to drain my battery over time.
Maybe a reed switch would be better as the power on signal?

Suggestions welcome! Thanks

2

Simple, just don't switch the Arduino on and off. Just keep it on and make it sleep. Simply wake it up as needed.

And yeah, the A3144 consumes quite a bit of power. If you need a magnetic switch (why?) you can indeed consider a reed switch which you can make consume less energy.

3

Err. Thanks, but that isn't the question.
This module sits for weeks unused with a 6v battery pack inside. No need for it to drain those batteries at all.

Magnetic switch - waterproof housing. No IP rated buttons therefore required.

4

OK. Mini reed switch feeding a TIP127 to turn it on.
Arduino puts pin high to hold that transistor on.
Code drops that pin to turn off

5

Can anyone recommend a better N Channel Mosfet to replace the TIP127 (its all I have to hand).
That transistor creates a voltage drop that I would like to eliminate as much as possible.

6

Hi,
Can you post a circuit diagram of your project so far, that way we can see how to provide some answers to your question?

I like the Hall-Effect as the toggle ON switch, maybe there is a way to then program some software to look at it as a toggle OFF switch after say 5seconds after your code has started running.

Thanks.. Tom... :slight_smile:

7

Sorry. Been out of town. I will sketch something up.
To be honest, it's looking just easier to buy a latching waterproof push button