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Larry Barello
http://www.barello.net
[Editors Note: This went sailing past on the email server one day, and seemed too good to pass up!]
Last meeting I demonstrated a two chip solution to converting R/C style Pulse (1.0-2.0
ms pulse at a ~30 Hz rep rate) to PWM (~1.8 kHz, 250 steps) The converter was driving an
L293, dual 600 ma full bridge driver and a couple of gutted R/C servos running as gear
head motors.
I have designed a PWB and finalized the software. Attached are the schematic and PWB
in gif form. I'll put the code and PWB files out on my web site RSN.
Spec:
- Jumper selectable:
Zero drive dead-band (0,4,8 and 12 us)
Zero drive action: brake or coast
Range (+/- .3 ms or +/- .5 ms)
- Atmel AVR ISP interface for (re) programming the chip
- L293 (equivalent) dual full bridge driver (2 x 1 Amp outputs)
- Two standard R/C inputs (V+, Gnd, Signal)
- Two outputs
- Motor battery connector (6-36v)
- 2" x 1.75"
I just ordered some proto boards and hope to have one or two assembled to show at the SRS
meeting this Saturday. The on-board 5v regulator is optional and won't be stuffed.
[Editors note: Here is a picture that was just sent to the list server!]
