SX Microcontroller Input / Ouput Methods

A2D and Stepper Motor Driver

From: Jordan Anderson [esp at funkt.net]

This source code and schematic are of a SX controlled 3 stepping motor controller. The end usage of which is camera movement control(maybe ;). Each motor only requires a 2 pin control. The setup also has a coarse/fine adjustment which changes the behavior of the steppers. The standard setting is that each cycle when a movement switch is depressed the motor will do 5 full step sequences, when the cf button and movement are selected the motor(s) will complete only 1 step.

The controller has the ability to move all three motors simultaneously (within a few micro seconds) in any combination of directions. The step sequence will not be affected if both directions were to be selected at the same time.

On the schematic the processer shown is a pic, I placed it on the schematic because it has a nearly identical pin configuration and I am not very good at making my own parts. The pin differences are: on the SX pin 1 is RTCC, osc1 and osc2 are not called clckin/out.

The schematic also shows 3 L293D chips, the motor drivers, any of the L293 chips will work. A better alternative is to use a Texas Instruments SN754410NE which is an improved functional replacement for the L293. The schematic shows 2 power connections to the L293 one is the +5v supply for the cicuit. The motor pwr is a seperate source for the the motor voltage. The TI chip accomadates 5v-55v @ 1.0A (I think).

I would like to do further work on this design and get it to a nice sleek workable form. Perhaps one of those sleek appmods that parralax offers. I would also like to mess with some different motors. The motor drivers have enable pins which currently are tied high. These could be tied into more pins on the SX perhaps using a larger chip, which would allow the use of regular motors in addition to the steppers. I also have some large (5A?) motor drivers made by national. If I can find some large steppers I might try them, but they are also setup for use with pwm for variable speed control of regular motors.

The concept of remote control of the device using the ethernet portal is also very interesting and I would like the opportunity to experiment with it. It would be fun to be able to control the motors and a camera or whatever they are hooked to over an internet or network connection.