Drill Motors

[gamefreak]

Hey all, just got back from Orlando Florida on a Technology Student Association trip and I have a few questions about some things I saw. One group, I hate them all....., built a thick metal box and moved it around using pullys, fan belts, bolts, and screwdriver motors to form a track system. The robot was fairly heavy and they claimed that it could get up to the speed of someone running( because they had to chase after it once..). They had it powered by 4 drill chargers with the AC end cut off, that way the batteries simply snapped in( saw the same thing not 2 weeks ago in the Kansas City Robotics Society) and it was secure. They controlled the drills by Innovation First speed controllers and drove it with a BOE bot brain.

My questions lie in the drills.

1. Where would one acquire cheap cordless drills of the same make?
2. Are Drills even a good motor for robots?
3. Do Drills drain a large amount of power?
4. Do Drill batteries suffer from memory effect?

[Steve Joblin]

1. Where would one acquire cheap cordless drills of the same make?
I would do a search for surplus drills (or surplus drill motors)

2. Are Drills even a good motor for robots?
Depends on a bunch of factors, but without knowing any of your requirements, I say "sure"... they are strong and have lots of torque.

3. Do Drills drain a large amount of power?
I'm sure they do... drill motors (and the batteries they use) try to balance "power" (or torque) with long run time.  For the most part, they are optimized for their task.  lots of power, but not long CONTINUOUS use... think of how you would use a cordless drill... drill a hole, stop, drill a screw, stop, drill a hole, etc. etc.  You typically wouldn't turn on a drill and just let it run without stoping.

4. Do Drill batteries suffer from memory effect?
It depends on the type of battery.  the newer batteries typically do not suffer from memory effect.  Part 1 of Battery University (http://batteryuniversity.com/index.htm) should provide you with a nice overview of all the types of batteries, and don't forget to check out all the great info on batteries here (http://www.societyofrobots.com/batteries.shtml)

[gamefreak]

I didn't know there was a battery university......

lol, thanks, I do some searching for drills then.

[ahab]

Cheap drills?

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=95094
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=93440

You can find lower powered ones cheaper. Check the lynxmotion.net boards, there are a few projects there based off of them.

I thought pretty hard about using drill batteries for my robot, but all-battery.com (from their ebay store) was cheaper per amp hour.

I know there are some Traxxas E-Maxxes out there with drill motors on them.

[Scheda]

You might also want to check out your local pawn shops. I stopped by one today to see what sort of electronics they had, and they had a TON of powertools, including probably 20 different drills, all really cheaply priced.

Sure, they are used, but that doesn't mean they are in bad condition.

[gamefreak]

i've never once been in a pawn shop, and there are none near by, What I love about my search for drills is that I'll find an 8 $ drill, with 20 $ shipping...

Thanks, I'll check out those links.

[Admin]

I used hacked drill motors for my first robot.

They come with gearing, wiring, batteries, etc - all the stuff you need except a motor driver.

Best yet, on the box it tells you how long the batteries will last, and everything combined you can get for like ~$20 at Home Depot or Lowes.

To hack it, I cut off the handle, wired the on/off switch to my motor driver, and made an attachment at the end to connect to a gear to drive my robot wheels.

Oh, and the people at dimensionengineering.com who make those nice motor drivers, they use drill motors/batteries on all their stuff.