Hi All, Last time I checked, we were in the business of making hydrogen peroxide-based launch vehicles. I don't believe one can make a decent version of peroxide using antiprotons. Call me goofy, but I think we've been getting more than a bit off-topic. Bill
On a slightly different tact, I would like to announce one of the developments we're pursuing for Gizmocopter - the propeller-based flight controls platform that is the lead in to POGO. One of the difficulties we've been trying to address is how to drive the propeller motors with a reasonably fast PWM controller. Currently, we use PWM controllers from Astroflight, which provide a 2800 Hz PWM drive to the motors that is controlled by a standard RC pulse width interface. This works, but our PC104 CPU needs to drive the motor with a 1.2 to 1.8 mSec pulse every 10 to 15 mSec, which is pretty time intensive for the rest of our software. Another option is to use a serial-controlled PIC-based PWM controller. This would be OK, except that the serial interface introduces a substantial lag in the control loop. The third option (which is what we're pursuing) is to convert our PC104's 4 on-board DAC outputs to PWM signals through the use of a NE555 (rigged as a sawtooth waveform generator) and a bank of comparators. The output of the comparators is then fed into a bank of enhancement mode monster FETs (for lack of a better word) which drive the motors. I found the information about rigging a NE555 as a sawtooth waveform generator from a Fairchild data sheet on the web. If you search on Yahoo with NE555, you can find the info in about 5 minutes. I've also created a schematic if anyone's interested. Bill _______________________________________________ ERPS-list mailing list [EMAIL PROTECTED] http://lists.erps.org/mailman/listinfo/erps-list
