Magnetic Switches - for $20 each!

I've wanted to add magnetic switches for a long time but I refused to pay the THOUSAND DOLLARS per switch for real ones, so I made my own on the cheap!

Here are the parts I used:
(As always, I have no financial interest or links to any of these sellers, I am only listing them to show what I used to build mine. Be sure to shop around to find the best price!)

DPST (ON)-OFF Toggle Switch -
12V Electromagnet-
4 Channel Mosfet-
Arduino Uno-
20mm x 1.6mm Aluminium Profile-

The Aluminium Bracket template is here-

And Follow me on Twitch to see it live and/or ask questions in real time!

00:00 - Intro
00:53 - What are they?
01:59 - The Parts
03:38 - Modifying the Toggle Switch
09:50- Mounting the magnet
11:45 - Test
12:49 - The SAS Panel
15:45 - Ingame Testing
16:44 - Safety
17:55 - In the jet
19:56 - Shenannigans

Intro Music-
Darkling by Kevin MacLeod

[thewarthogproject]

Update- A few days short of 1 year later, two of the nails fell off as the bondic glue gave up. It was an easy fix, however I used a two part epoxy this time. They will never come off again.

[GoSlash]

I have a suggestion. Suppose you use permanent magnets to hold the switches in the on position, but *counteract* them with electromagnetic windings when you want them to disengage. This would greatly reduce the current draw of the setup as well as eliminate the need for cooling. Instead of applying constant current to keep the switches engaged, you'd only need a short pulse to disengage them.

[PeterKNoone]

Wow. The WAF (wife acceptance factor) of your hobby is nearing zero. You are my hero, great stuff as usual. Makes my pathetic sim-racing cockpit look pretty sad (I still love it even if my wife doesn't)

[CYMotorsport]

oh no.... I was running out of inspiration in sim racing as I've gone as far as i've been able to find online re: DIY electronic tinkerers. Your complexity just blew that away haha looking forward to this rabbit hole

[frollard]

Worth adding - a lot of the cheap mosfet boards don't have a back emf protection diode (should be one inside the mosfet but easy to blow out) - inductive loads like that magnet could have an appreciable pulse that the mosfets won't like.

[benqenobe]

Ha, amazing work. Just when I think you are basically done you go and add another level of realism.

[TerryLawrence]

I love the amount of work you have done on this project. Making all this public and open is awesome . I made a similar switch setup but I use a permanent magnet on the end of the nail. This magnet sticks to the electromagnet by default to hold the ON position. Simply pulsing the electromagnet in the same N/S polarity as the permanent magnet will push the magnet away. This means only a brief pulse is needed on the electromagnet.

[ChadCyr]

The magnetic switches are like ASMR. So satisfying! Bravo!

[lexeindhoven]

Would recommend looking into solenoid driver ic's. They limit the current after a set time. The hold current is much lower thus less heat

[thewarthogproject]

Sorry all- I fixed the broken links in the description!

[DerSolinski]

Magnetically hold monotary switches are such gems.
A lot of machines used them as main switch in conjunction with e-stops.
Also made sure they wouldn't start up after a blackout.

[John-gmty]

dude, the level of effort and workmanship and ingenuity is off the charts.
fuck me it's impressive.

[ollyk]

If you are worried about the magnets dieing, one standard technique with electro magnets is to lower the voltage. You might be surprised how low you can go.

Fantastic job!

[johnwickham]

This is an insanely clever design. I've been thinking for a while about toggle switches that will actuate themselves and could never come up with a way to do it. Really dig this.

[steffennilsen]

Regarding the electro magnets getting too hot, you can pwm modulate the powerdraw so it pulses on and off quickly with a mosfet and tune it so it will still hold the switch but use less power overall and thus not get as hot. Edit: I see below someone has suggested a dedicated solenoid IC and it would be an even better option. Another way to reduce power draw is to increase the surface of the part to hold, seeing as its a small rod it has a very small surface compared to the magnet, if you could have a flat wider surface you would need less power to hold it

[prairiedawg]

As you're using an Arduino to do the switchng I'd definately consider PWM-ing the solonoids. So for example pulse ON for 1 second to actuate then switch to <whatever> percentage PWM to hold (you'll need to do a bit of trial & error so it feels right). As a benefit you can probably do away with the fan. NOTE don't even try PWMing without flywheel diodes though!!

[benoitmalenfant]

Great stuff! You might want to look into using flyback diodes at the output since this is an inductive load, there will be massive voltage spikes at turn off time, those can damage the mosfet, putting a diode in parallel of the solenoid but in reverse polarity will prevent that

[cageordie]

Man, this takes me back! In the early 90s the company I worked for did a startup simulator for the Harrier so they could practice procedures for hot and hung starts, etc. We got a cockpit built and installed instruments and displays. The two impossible tasks were barrel gauges and these switches. Both extremely expensive and impossible to find used. This was long before Internet and Ebay. We eventually subcontracted to have the gauges built for us. I don't know where we eventually found a start switch. Our engineering manager spent his weekends going round aircraft scrap yards, and aviation museums looking to buy one somewhere.

[Builder]

I've seen a lot of stuff on "makter" youtube...woodworking, metal working, cars, off the wall vehicles, smart homes that feel like they're from the 22nd century, diy-ultralight airplanes, (ya'll know which channels I am talking about haha) but the quality of your work (I mean there is nothing bodged there) and dedication that you put into this project over this many years is something I've never come across. Not on YT, not in my private life, not in my professional life.
Keep it up!

[kennethjanczak]

Some project you got there....
Impressive.
Thanks for taking the time to make the video and share your project....