H-Bridge

The H Bridge DBH 01C is a bit more trouble than I was expecting. We spent quit a while trying to get it to behave with PWM just to one pin, but is needs PWM at both. One direction is solid but the other is unstable. . To do a proper, straight connection could mean two timer comparators for one motor, wasting a timer. Or hacky PWM outside of proper timers. With a couple resistors (each channel) off of the PWM I could use two OC outputs to force whichever pin low on the H-Bridge, wasting two outputs.

An old fashioned quad NOR (7402) is in order. With inverted inputs the logic will keep the PWM on one pin and direction on the other. As far as work, it's about the same as resistors and using more outputs.

A few 74F02 are on order from Digikey. I like the "F" gates since they are ESD tough (unlike HCT or even LS) and drive pretty hard.

Motors

The nacelles are a bit leaky. Not sure where the leak is yet. One bit of good news is the motor noise doesn't seem to be interfering with the receiver; and We don't even have the filter caps on them yet.

Journal CW33