R2 D2 Electronics Question - Electromagnets

[Dewback_Rider]

Here's a question for anyone with R2 and/or electronics knowledge:

I have a design idea for the center leg deployment using a 12V DC electromagnet like one or two of these:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=200363837823

Would/Will this interfere with any of the droids internal components such as stored sound bytes, or other electrical systems?

Power would only be turned on to the magnet during the lifting and lowering of the center foot.

 

[jonny5]

I can't see the eBay auction from this PC to get all the specs, but I would think a 12v electromagnet probably isn't powerful enough to wipe the thumb drive or flash card that your sound files would be stored on.

You're thinking of using these for top/bottom end-of-travel position locks to keep the leg extended or retracted right?

Can the bolts be set as 'normally thrown' so they are extended to the lock position when off and only powered to retract the bolts when the leg moves? In that case power would only be needed while the leg is moving, and the magnets can be shut off once the leg locks in place, there would be minimal activation of the magnets.

Droid builders have used strong rare earth magnets all over their bots for various things like attaching the restraining bolt, or the center hubs on the the shoulders, and holding rear access panel closed. I don't think this would be all that different and its only an intermittent thing.

Of course the only way to know for sure is full scale bench test.

 

[Dewback_Rider]

Here are the specs:

"For sale here is one lot of four (4) cylindrical electromagnets. Each electromagnet measures 46mm in diameter and 36mm high with two 12mm protruding 4mm x .70 threaded connection terminals.

Polymer body encapsulates the laminated steel wound core and includes four steel sleeved 3mm mounting holes in a rectangular configuration on 19mm by 33mm centers. The tripolar ground surface faces are additionally protected by an bonded circumferential steel band 1.75mm thick by 6.5mm deep.

The cross-sectional view photo below exhibits the hermetically sealed core windings which are comprised of 132 turns of 24ga solid copper wire having a DC resistance of roughly 1.5 ohms. Zero air gap flat plate loading of one of these electromagnets will generate approximately 14lb of holding force per volt of applied EMF.

For example, supplying 6VDC to one of these will exert 84 lb of lifting force. Perfect for student labs or experimentation. Higher duty cycle usage may require a drop resistor."


I was actually going to be using them as a "touch and release" lift mechanism that would move the leg from the stowed position down to the bottom where a bar on the ankle assembly would lock into car door locks, securing it. The magnetic drop system would then release and back off an inch, removing the actuator rod and motor gears from the direct line of fire for any vibration to prevent shearing of gears.

When it comes time stow the leg, the actuator lowers the magnetic plate into position, activates the magnet to grab the ankle plate. Solenoids would release the door locks, allowing it to travel back to the top of the glide path to a second set of locks to stow it securely.

So the actuator would purely be a means of conveyance.

Thoughts? :love

 

[Dewback_Rider]

Perhaps with the ankle secured in the car door locks at the bottom, I wouldn't need to back off the actuator, as the locks and the frame would absorb any shocks?

I mean if the car door latches are strong enough to hold a car door securely, it should hold up my droid, especially if I had two in place at the bottom.