I have been working on a small bot that is going to be radio controlled (for now) using a 2 channel futaba. It has a forward, back lever (center is neutral) and a left, right lever (center is neutral). I built up the circuit in Gordon's book on p. 353 for the H bridge controller. I breadboarded it tonite and it works fine. I will be building up 2 of them over the next few days to use to drive my motors. It is a 3 wheeled bot, the front 2 wheels will have the motors attached directly to them, the rear wheel is just a caster wheel. The motors turn at about 50 rpm. I am using 7 inch wheels, so it is a fair amount of speed. Anyway, I can see how the forward and backward control will work. I am going to use that servo to apply the 5-6V to the H bridges by means of a toggle switch, DPDT, momentary. The H bridge will be connected to the +V all the time, which is a separate battery. Now I am having trouble picturing how to turn the bot. I know I have to cut power to one of the wheels to turn, but I cannot seem to picture how to do that with the left right lever. When the lever is neutral, the bot should go either forward or back. When I want it to turn, I push the left right lever either to the left or the right, but I am not sure what type of switch to put in to stop one motor, but keep the other one running to execute my turn. It seems that if I use another DPDT, I won't have a neutral position if it is placed between the forward, back lever because then it will interrupt all the power going to the wheels. If I place it before the forward back lever switch, then, same problem, the control voltage will never make it to the forward back lever switch. I know this has been done before, I just seem to be having trouble wrapping my brain around the specifics of how to execute a turn without messing up the rest of the system. Any suggestions welcomed. TIA, Joe
- posted
17 years ago