I have no experience with Arduinos. I can spell PC pretty well, but not that iOS thing, MAC?
I have two problems.
my kids gave me an Arduino Starter Kit last Christmas and I haven't even opened the box yet and they'll soon be back for this Christmas.
I need to coordinate the revolutions per second of four (4) 12VDC motors that I want to use to build a poor man's screwjack. ( I don't know if the motors are a stepper, servo, or none of the above. I'm planning on cannibalizing 4 linear actuators.)
My question is, Is this something that an Arduino can do?
If the answers are Yes, I'll be back in a couple of weeks with "how do I do it ?".
jmhine:
My question is, Is this something that an Arduino can do?
The best I can say is "probably".
You need to know exactly what sort of motor you have, you need a motor driver board to sit between the Arduino and each motor because an Arduino cannot handle the currents required by a motor. And you also need to tell us exactly what control you want for the motors.
For example if you want to control the speed of a DC motor you need some sort of sensor to measure the speed.
You can use an Arduino, and first of all you should open the box and connect it to your PC. The starter kit contains motor control demos for becoming familiar with such stuff. For 4 motors you also need a strong power supply and motor driver modules.
I cannot say more unless you describe the intended device more precisely. Are the 4 rods connected to some platform? How then can you avoid an initial and persistent deadlock? A different solution may be easier to control.
With the correct sensor, like a PIR xmit/rcv pair, something as simple as a flat on a round shaft can be used to detect rotation. It probably would work too on the screw shaft and not require as much processing power. Or, maybe a hall switch sensing a magnet glued to the shaft.
jmhine:
I need the motors to turn 4 threaded rods at the same rate. (same revolutions per minute)
There is another important piece of information, does the speed need to be tightly controlled? (And what speed and what range of error).
If you can't arrange for the shafts to be geared together and driven with a single motor I reckon stepper motors would be the easiest to control for synchronised motion. However stepper motors generally don't do high speeds.
To answer your questions about intended use. I've built an 8-foot long workbench for my shop in which I've embedded 3 bays/silos. Hidden under the workbench in the silos are a table saw, a router table and a bench planer. I've built scissor lifts for all three tools and the scissor lifts are powered by linear actuators.
The link below shows the bench planer rising out of the workbench by a scissor lift.
While this method works OK for the router table and the table saw, the bench planer is so heavy that after 3 or 4 uses, the scissor lift literally self destructs spewing out chunks of twisted metal and shredded oak beams. The video shows the 3rd scissor lift that I've built for this tool, each lift taking me 3 to 4 weeks to construct.
So I wanted to try a different method to raise and lower the planer. I was thinking of a threaded rod in each corner of a platform attached to motors could raise and lower the heavy planer.
Can’t see you photos, but sounds like your “dead lifting” all that weight.
You sound very handy with tools, have you tried to use corner mounted pulley weights and / or a couple of springs say out of the forks of a junkyard motorcycle so that you could raise and lower the planer with minimal effort?
jmhine:
While this method works OK for the router table and the table saw, the bench planer is so heavy that after 3 or 4 uses, the scissor lift literally self destructs spewing out chunks of twisted metal and shredded oak beams.
My browser won't show your video. Can you post it on YouTube?
How heavy is the planer?
How far do you want to be able to lift it?
What about using gas struts to take most of the load - like are used to lift the tailgate of a car. I presume they are available from car breakers.
What about using a screw-jack from a car?
I think if you have levers to steady the motion you could do the lift with a single screw-jack.
Could you "rotate" the planar into position so that maybe half the weight is taken by the hinge?
