Electromagnetic Screwdriver

[Rasori]

Hey all, I've been toying with the idea of an electromagnetic screwdriver, allowing for the convenience of a magnetic tip and the sensitivity of a standard tip. Yeah, forgive me, I'm bored.

 

Anyway, toying with the idea I've been wondering about power. I'm sure I can make an electromagnet with batteries, and given the low mass of the screws, probably (haven't gotten around to testing it yet) even with just one AA or similar. Worst-case, I've been reading that D-cells are quite useful in these things.

 

What I've been wondering is if it would be possible to use a capacitor bank. I know they're usually used for high power for short periods, but I also know that they can be used for other purposes. For example, I have a squeeze dynamo LED flashlight which doesn't need to be squeezed every time I want to turn it on, and from wikipedia I can see that these are sometimes capacitor-powered. In the end, my preference would be similar to this--a battery-free option. I'd like it not to be obnoxious: squeeze the handle once for around a minute (or more) of magnetic awesomeness, which hopefully would last through a standard working session without needing to recharge if left unused. Or, if a crank dynamo, turn the crank a few times, perhaps?

 

I'm not familiar enough with the electronics to know if this might be possible without simply building it and testing, as I can't get a value for the resistance of the coil. I'm not asking anyone else to do that, but if people know offhand that it would be possible, I'd be more willing to splurge on the components to build it (I'm a college student with no money for pizza, let alone components which won't work), and if people know offhand it wouldn't be, I'll stop following this little path.

 

Thanks for any advice!

[TonyMcC]

You can have a battery free option by making the tip a permanent magnet. In fact you can buy one, just google - magnetic screwdeiver -. In order to get a useful amount of magnetism using a charged capacitor you would (IMO) need a coil of many turns with high resistance. Many turns to provide the magnetisn, the high resistance to prevent a rapid discharge of the capacitor.

[Mr Skeptic]

I think the constraints would make this screwdriver too inconvenient. A squeeze handle would make for an abnoxious screwdriver, the shaking to charge version would be pathetically underpowered, both would take way too much time to charge to be of much use (compare power consumption of an electromagnet to an LED, and then the size of the flashlight to the size of the screwdriver).

 

Here's an idea: use two different screwdrivers, or at least two tips. One magnetic and one not. Would be much smaller and more convenient than the large one. Alternately, there's plenty of electricity from the wall outlets.

 

But if you want a practical idea, an electromagnetic tip on the battery-powered screwdrivers might be worthwhile.

[Rasori]

Haha you guys take the fun out of passing time with idle thought. Of course I could use two different screwdrivers, but that eliminates the project aspect of it all. The concept is to enable someone like me who does a lot of tinkering, sometimes with sensitive electronics and other times just pulling stuff apart, and who gets attached to that particularly comfortable ratcheting screwdriver, to get both options with low hassle. The end result would, in my mind, be a single ratcheting screwdriver, with one set of tips, which could be both magnetic or non-magnetic depending on requirements.

 

I do like the idea of the already-electric screwdriver, but tearing one of those apart is a bit beyond what I had in mind.

 

It sounds like, if I really do want to go this route, standard batteries are the way to go rather than capacitors, and there's no point working out any dynamo-based option. At least when dealing with batteries I'll be able to handle the power considerations more easily on my own.

Edited December 2, 2010 by Rasori

[TonyMcC]

If you are looking to make something that will work out of interst in electricity and electronics rather than making something that might be commercially viable (i.e. make money) then I wish you success. Best of luck - enjoy yourself.