3-axis bipolar microstepping motor driver with integrated joystick control!

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It's been a slow start on the Arcsin. I've been doing hardware design and firmware development at work for the last two years, so it has been tough to find the motivation to do this kind of stuff at home after doing it all day at work. However, things have changed. Our R&D budget was cut and our team is downsizing. I had to pick up some debug responsibilities and I won't be doing HW stuff for the time being. The interesting thing is that a couple of weeks after I stopped doing this stuff at work, my hobby interest was re-kindled. Very cool!

Arcsin2 features:

• 3 axis bipolar microstepping motor driver.
• PWM (Pulse Width Modulation) technology.
• 20Mhz onboard microcontrollers for precise digital control.
• Fixed off-time current chopping. No bulky series resistors needed between the controller and the motors.
• Jumper selectable full, half, quarter, and eighth microstepping.
• Output current fixed at 3 amps per phase
• Fully integrated digital joystick control for accurate positioning of the cutting head. All three axes of the Arcsin can be run without a PC for testing and/or motor spinning.
• Parabolic ramping algorithm on joystick control for higher motor speed and silky smooth acceleration. Can be enabled/disabled via onboard dipswitch.
• Joystick speed potentiometers for each axis, or you can jumper them together so a single pot controls the speed for all three.
• All DMOS H-bridge power section delivering 3A per phase continuous(6A peak) at up to 48V.
• Idle current reduction.
• Thermal shutdown @ 155 degrees Celsius.
• High speed Optoisolators on step/dir signals to reduce signal noise and protect PC.
• Separate power planes for logic and opto supplies that can be jumpered together or split for ultimate noise suppression.
• Onboard 5v regulator for Logic-supply.
• Ribbon cable connector for additional slave driver when 2 motors are needed for a single axis.
• Direct parallel port connection.
• 30Khz max step rate.
• Optional C axis step/direction outputs.
• 12v @ 1A spindle motor and coolant pump output transistors.
• Home, limit and Estop inputs
• Heat sink integrated into chassis

I've switched to mostly SMT parts for this rev of Arcsin mainly because I don't have the time to be soldering these things together in my "spare" time. I picked up an old Zevatech pick and place machine and I've done a few runs of boards for work on that thing. It works real well once you get it programmed and I'm looking forward to seeing how it works for the Arcsin.

I've also switched to an AVR micro instead of the PIC for this time around. AVR's have interrupts on every pin, programmable pull-ups on every pin, and they run an instruction in one clock cycle instead of four like the PIC I used on the original Arcsin. I also wanted to play with a new architecture so I chose the Atmega88 for this version.

Fab E: Will this be it?(06.15.2008)

Housing first Prototype (05.15.2008)

Arcsin Housing Design (02.6.2008)

Fab D refinements: Opto Isolation messed up! (01.29.2008)

Fab C: Arcsin progress! (01.11.2008)