Electromagnet for chair bondage

[tkv]

I like my chair bondage as much as everyone, but I can usually only do it for an hour or so before my arms get tired and sore from being held behind my back. Also opening the locks can become a bit difficult. So I came up with this contraption which should allow me to lock my arms to the side of the chair fairly comfortably, possibly for several hours.

It's basically two pieces of plywood with a hinge at the bottom and a chinese door electromagnet to keep it closed. Each side has a small hook for the d-rings on my cuffs, and once both cuffs are hooked you just bring it closed by moving the arms forward. It attaches to my bondage chair with some screws and wingnuts and also provides a ring on the front side for crotch ropes. There's also a bit of webbing to stop it opening all the way and a button to switch it off temporarily, if I accidentally slam it shut while tying my ropes for example.

The electromagnet is from aliexpress, runs on 12V at about 300 mA and cost about 20 euro. It claims to be able to hold 180 kg, but I'm not sure. It's possible to pry this open even with just fingers, although it is difficult. Of course once you're sitting tied up in the chair there's very little leverage to be had, so it should be secure enough.

Pros and cons that I can think of, compared to my usual setup:
+ no need to align the chair with the key drop (hooks in the ceiling)
+ instant release once the power is cut, no locks to fiddle with
+ seems reliable, there's no mechanisms to get stuck and it's fail-safe
- emergency release is a bit difficult, cutting the cuffs with a knife might not be feasible

I did cut an extra groove for a cable in there with the intention of making an emergency release button, which would cut the power but at the same time activate something else. Say, a shredder with an appropriate amount of bills primed? Some more thinking is needed.

Small extra story about cuffs and padlocks. I was doing a session in the chair, there was some urine drinking involved and I wanted to get out already. The keys dropped and I started to work the key into the lock, but somehow kept fumbling it up. I kept trying, got a bit frustrated and I guess kind of forgot where I was, because I thought to myself "I'll deal with this cr*p later" and was ready to stand up, only to sit there a few moments feeling stupid with my hands still tied. I checked from the video later and it had taken me five minutes to open the padlock.

[Gregovic]

Very nice setup. You could also have the cable and a pair of cable cutters within reach so you can cut the electrical cable (At 12V this is safe, DON'T do that with a mains powered device obviously). Having to fix that would be annoying enough for me to probably make it an emergency only option for me.

You could also power the magnet from something like a drill battery pack. At 300 milliamps a typical 12v drill battery pack would take about 4 to 5 hours to drain below about 9 volts (which in my experience is roughly the cutoff voltage for the battery protection system to stop the battery outputting any volts). Then you have a hard limit on how long the magnet will remain locked.

[Shannon SteelSlave]

Very nice setup. You could also have the cable and a pair of cable cutters within reach so you can cut the electrical cable (At 12V this is safe, DON'T do that with a mains powered device obviously). Having to fix that would be annoying enough for me to probably make it an emergency only option for me.

You could also power the magnet from something like a drill battery pack. At 300 milliamps a typical 12v drill battery pack would take about 4 to 5 hours to drain below about 9 volts (which in my experience is roughly the cutoff voltage for the battery protection system to stop the battery outputting any volts). Then you have a hard limit on how long the magnet will remain locked.

Could one gut a battery charger to make a nice terminal socket for said drill battery? Just solder wires to the terminals + and - and run through the grommet to the magnet terminals?

[tkv]

Could one gut a battery charger to make a nice terminal socket for said drill battery? Just solder wires to the terminals + and - and run through the grommet to the magnet terminals?

One could, but I prefer my plug-and-play system. My mains timers have been reliable enough for now and the emergency release would be more for the situations where I need to get out right away, rather than as a backup several hours later.

My long-term project is to create a Raspberry Pi driven device that would control the release among other things such as vibrators, TENS units and possibly a shocker. I even have a broken UPS with plenty of sockets to use for this. Should be done Any Year Now(tm)

[occorics]

My long-term project is to create a Raspberry Pi driven device that would control the release among other things such as vibrators, TENS units and possibly a shocker. I even have a broken UPS with plenty of sockets to use for this. Should be done Any Year Now(tm)

if you need inspiration, this is my modular RaspberryPi based system (in case you haven't seen it already):
http://forum.boundanna.net/board/viewto ... 12&t=11419
http://forum.boundanna.net/board/viewto ... 12&t=11544

I connect most devices via I2C and use RJ-45 connectors. That way I can use network cables to that I have tons of anyway.