A small project for shooting.

[Twisted Transistor]

Hi, I'm new to this forum and I joined because I'm hoping to get some help as well as learn more about electronic components. I have some experiance with small electronics and small projects, however I ask that you explain things in very simple terms as I am at the novice level at best with electronic components. Please bare with me as i explain what i am trying to build.

I am an avid shooter (pistols, rifles, and shotguns) and I practice regularly and always just for fun. Punching holes in paper is fun, but it gets boring after a while; especially when the paper isn't moving.

What i would like to build is a small ferris wheel type target that has either 4 or 6 cardboard targets on it that are 6'' to 8'' in diameter (approximantly) and have an electric motor that is battery powered to turn it. I have a motor that I am sure will turn it, but I need to make a small circuit that is going to make the motor draw more power. I am thinking about wiring a couple of 9 volt batteries together.

The more i have is a small RC airplane motor, 600 class if that means anything. Its a brushed motor and is about 1.5'' in diameter and maybe 3 inches long. I am going to put the motor at the base and use a set of pullys to turn the wheel (obviously I don't want to shoot the motor)

The wheel it self is just going to be thin wood bolted together, weight not to exceed 10 pounds and about 4 feet in diameter.

How can i build a simple circuit that will allow it to draw more current from the batteries? I want it to spin fairly slow, not more than 15 RPM or so.

any help is greatly appriciated.

 

[cr0sh]

First off, I don't think 9V batteries are going to cut it for that motor; they only put out 500 mAh or so each - you'll likely drain them flat in no time, as that motor will likely pull a lot of current, especially driving that big a wheel thru the amount of gearing (belts and pulleys) needed. Which brings me to that - you're going to likely need a couple of sets of pulleys and belts to gear it down; and that's if you make the last belt drive hooked to the four-foot wheel (for a large ratio) - otherwise if you are wanting a smaller pulley at the hub you may need more sets of pulleys; its really unknown until you know what the RPM of the motor is under the load. Such motors were made for driving an airplane propeller, and not really for the use you are planning - I am not sure if it will be able to take the stress or not (on its bearings, mainly) as the bearing is likely a thrust-type bearing, and not a radial load bearing (as such a load would be with a pulley - that is, a load perpendicular to the shaft, instead of parallel with it, like a propeller pulling/pushing a plane would be). You may want to investigate using a different motor; perhaps a gearmotor designed for such use...

 

[moidut]

You can make it moving with the help of some ropes and a set of pulleys. One simple way is change the direction of motor After reaching cardbaord in one end. That means change the rotation to next direction with the help of some op-amp circuit. I am attaching one sample motor driver circuit i found somewhere in web.**broken link removed**

 

[bryan1]

A far easier way will be using a 12 volt wiper motor off a vehicle, these have a worm drive gearbox and the beauty of the DC motor is simply varying the voltage will vary the output speed. I did a U-tube vid a couple of years ago showing the speed V the voltage and current so that should give you a good idea to work on

YouTube - ‪ruddycrazy's Channel‬‎

Cheers Bryan

 

[Twisted Transistor]

Thanks a lot for the help guys. This advise is very helpful. I will definently check out a 12 volt wiper motor. I'll look into it some more and maybe got a a junk yard and yank one out.

edit- I just had the great idea of using the speed controller for a model train set that i have. I have not clue what kind of power it puts out, but i can run a train at a pretty good clip.

 

[EternityForest]

You could also use a large servo motor hacked for continous rotation. google has several tutorials.
it shouldn't use that much torque if the wheel is balanced.
do you use bismuth or lead bullets btw?

 

[Twisted Transistor]

I cast my own bullets for one of my guns, its just pure lead. Sometimes I mix a tiny bit of tin in it to harden it a little.

.22lr is basically pure lead.

Obviously my high power rifles have copper jackets on them, but i wont be shooting those at this. This target is for no-so-powerful guns like handguns and small bore rifles.

Right now I'm thinking about using the model train motor control and any reasonable electric motor i can find. I will look into servo motors. If they aren't too expencive I will buy one.

Im somewhat familiar with sevos because I also fly RC aircraft. Of course those are fairly small electric motors.

Originally I was going to use RC airplane equipment and make it completely remote control, but I dont want to risk shooting my expencive radio equipment. I could weld steel plates together and protect it though...