more arduino use

[dsteve]

this is an extension of the post by diyguy. It is going to be a long time before there are humanoid robots that can tie you up, but here is an idea for today. The arduino is a nice board for controlling devices like motors. For example, it can turn a motor on and off. It can also respond to sensors. The sensor I have in mind is a limit switch. This is a switch that is closed when something moves to a particular position. Here is the setup:
There are four gearhead dc motors positioned to pull you into a spread eagle position. You buckle on leather wrist and ankle cuffs and attach them to chains. The chains are on reels that are turned by the motors. You program the arduino to wait 5 minutes and then turn on the motors. The motors turn until a spot on the chain hits the limit switch. The arduino then turns the motor of and holds the position. After either a predetermined time or a random time the arduino reverses the motors to release you.
You could also use a ratchet device to hold the chain. This would require additional mechanism to open the ratchet.
Another idea would be a post tie. This would require several motors with reels for rope. You would stand with your back to a post. Take the slack rope from the motor and reel, pull it across your body and attach it to a hook on the other side of the post. Same idea. The arduino would turn on the motor and tighten the ropes until a limit switch is hit.
Gear head motors strong enough to do this are $20 so the whole setup would be one or two hundred. There are obvious safety concerns about the release, but a good builder could overcome those difficulties.
I hope someone builds one and lets me know about it.

[nitro]

Having built control systems with limit switches I would not trust them as the only stop point control in a situation like this. We would use double limit switches (in a non life threating control) and would still experience random faults. The motors you are referring to could easily cause a dislocation or worse. OK for release (with a backup) but not for tension control in SB.

[diyguy]

Rule #1: Always have a backup release.

Rule #2: Electronics and computers are never fail-safe.

I'm sorry, but i would use an Arduino only for more simple release solutions. I'd never trust any electronic part which "should" prevent me from being ripped apart (okay, maybe thats a bit exaggerated

Having said that, I'm dreaming of all sorts of devices which automatically tie you up, wrap you up, stretch you, etc.

[red_alert]

I'd never trust any electronic part which "should" prevent me from being ripped apart (okay, maybe thats a bit exaggerated

One tipp:
I used an electro magnet for my release. My Arduino was set to release me. The electronic and the power supply (a battery) was so constructed and calculated, that after a maximum of two hours the battery was empty. And the electro magnet was not powered any longer.
Of course this should not be our only release.

But it is pretty fail safe (if calculated and constructed right)

Greetings
red