Futaba 8UAF and Tamiya R/C tank - programming question
Incidentally, if anyone knows how Tamiya programmed that module to sense what JWLaRue calls an "immediate overtravel condition," or a way to have the Tx send a signal like that, please post.
As a further explanation to those who know a lot more about RC than I do and have posted in this thread, but don't have a tank, here is a little clarification. Simply sending a signal like a channel 5 "landing gear" signal would not be enough. The guns only fire when you flip the stick fast. In other words, the guns don't fire just by sending a servo signal to the end of travel in either direction.
You have to set the trim slider switch all the way up (or down) and then flip the stick fast in that direction. I mean FAST! if you slide the trim up and then move the joystick up at normal speed, the barrel simply elevates and the cannon won't fire.
Tamiya did this because ground frequency radios usually have 4 channels or fewer. These tanks will work with a 2-channel radio, although you can't roll and fire at the same time if you only have 2 channels.
The 4 channels are for throttle, steering, turret rotation, and barrel elevation. Tamiya was pretty clever to figure out how to add the ability to fire two different guns independently of those four functions and still use only 4 channels! The computer inside the tank can apparently sense a signal spike in the over-travel positions on channel 3. Simply sending a "slow" signal on channel 3 will move the cannon barrel up and down but won't fire the guns, regardless of where the trim dial is. Freaky huh?