The servo is not a problem its only $4 US and its all ready put together to my gear head motor.
Can I use a 24 Volt 200watt motor attached to the 08M ?
Rickharris if this is possible would you please elaborate, I would really appreciate it.
Thank you all.
I will post my progress.
NOT directly! - You need an H bridge, what type depends much on what you intend to do with the motor/servo system. In some cases a simple 2 relay bridge will do - In other cases things need to be complicated and PWM/PID loops/transistor/MOSFET Driver systems are required.
My plans & thoughts:
First I have to say I haven't yet done this yet, but at some time will need to drive some geared 180 watt DC motors using Picaxe - My thoughts so far have been:
For my application I do not need to worry about the 20ms frame rate of a standard servo so the picaxe should run fast enough even at 4 MHz my inputs will be direct to the PICAXE.
My application is to make a fairly robust linear actuator. I run a suitable nut (perhaps a ball nut or a lead screw) up a threaded shaft where the shaft is drive by the geared motor. The ball nut provides a linear push/pull output proportional to the number of times the shaft rotates.
RS components carry both lead screws and Ball nuts (the latter being much cheaper.) It is possible to make your own lead screw but a standard nut actually provides considerable friction unless very well lubricated. Nylon nuts can provide much smoother running. Alternative systems using toothed belts with the output actuator attached to the belt are even cheaper and do work.
Initial trials with an electric drill motor look hopeful.
At school, on a small scale, we have used a tube with LED/LDR at each end as the distance between them increases the LDR resistance increases, this can be used to control the position of the nut on the linear actuator - As things go it doesn't provide good repeatability of positioning though - at least as far as we tried it.
One possibility is to build a MOSFET H bridge - there has been some discussion on this in this forum so a search should throw up several threads. As I don't need to run to PMW even simple relay H bridge may suffice.
I intend to monitor the shaft rotation using a slotted disc and LED/Phototransistor. I intend to make the DC motor act like a stepper (in a way) so I can count revolutions of the geared down output shaft - this way the software is closed loop and simple to do:
Code:
Turn motor on in required direction for xx revolutions
Monitor shaft counter until count = xx
turn motor off.
Provided I keep track of where the nut is I know the relative position of the output - A strategically positioned micro switch can mark end stops/centre position.