Hi All,
I am only new to the world of arduino so be patient with my questions. I have spent the last couple of nights trawling through the forums and reading up on the various projects people have done. I am attempting to cut corners by trying to find similar projects to the one I am wanting to accomplish and havent really found anything as yet. I also have some questions which may relate to my particular project only.
So I thought I would just ask for advice.
I am making a steel plinker (silhouette target for a rimfire rifle) with an auto reset function. The idea behind the plinker is that once I shoot four targets down (they are attached to a base plate via hinges) the last target activates a switch which controls a motor which moves an arm and resets the targets then moves back to its original position. I dont have the exact weight of the targets yet but they will be quite heavy (most likely 5kg above total). I have toyed with the idea of using a high torque digital servo (I come from an RC background so know there are expensive high torque servos) to move the arm and have coded it already. But... I dont think the servo will be capable of resetting the targets so I looked into using a dc stepper motor and relay setup. The problem with that is I am not so sure how to set this up. I have watched many videos and read other posts but Im confused now.
What I would like to know is what are peoples thoughts on my idea to reset the arm? servo, dc motor, dc stepper motor other?
Thanks
so I looked into using a dc stepper motor and relay setup.
A stepper motor is told to step n number of times. It is NOT turned on and off via a relay.
If you only want to do the reset when all the targets are down, you can do that easily using a switch for each target, and a car windscreen wiper motor. The design would be that the motor/drive mechanism moves through a cycle which pushes all the targets up and then returns to the rest position. Connect the target switches in series so that the motor is triggered when all four targets are down. This will cause the motor to go through one cycle and then park in the rest position.
If you don't have a suitable wiper motor assembly you can create your own equivalent using a DC motor/drive mechanism, limit switch and relay. The motor would be driven via a relay which is self-energising (the output is connected to the input) and the self-energising circuit is broken by the limit switch when the motor/drive is in the rest position. If you're DIYing it, the drive mechanism could be as simple as a piece of string tied to a crank.
a car windscreen wiper motor.
Car window actuators may be better. And many have a rack-pinion that's plastic and would probably be OK outdoors with the motor/Arduino in a box. Hit the junkyard. And an old 12V car battery should run this for months.
DISCLAIMER: Mentioning stuff from my own shop... but this stuff is widely available on ebay etc.
You will need limit switches for the motor positions, and the targets. Simple microswitches would be OK, like THESE:
A small 2-relay board with optical isolation would be good to run the motor: Like THIS: The two SPDT (form C) relays can then do FWD-STOP-REVERSE.
Question: How thick does mild steel need to be to not be deformed by .22LR ?? The backstops on my highschool rifle range were 3/8" plate.
terryking228:
Car window actuators may be better.
The windscreen wiper motor assembly provides the parking circuit, which is the only control logic needed here. I don't see any need for electronics at all. You could do it with a window lifter motor but you'd need a slightly more complicated circuit to make it cycle and park.
Hi thanks for the replies guys, I really appreciate the feedback.
I was heading in the direction of a dc motor but now thanks to you I have other avenues. Sounds like a windscreen wiper might be a simple enough solution. Ill keep researching the mentioned ideas here.
As for the steel I have been researching this and most have suggested 6mm minimum. This I will test thoroughly as I dont want any issues with this aspect of the project.
Thansk again.