I'm brand new to letsmakerobots and newbie of picaxe world...so forgive me for the noob question.
I’m working on a project that involves controlling a brushless ESC (with reverse option) with a microcontroller instead of the R/C receiver. Essentially I need to be able to run the motor in both directions alternatively, at preprogrammed speed, using 2 switches eg. Start run in CW and start run in CCW.
Basically what's shown in the video is what I need.
Is a project that can be implemented using Picaxe? I know that Picaxe 08M has 2 Pwm outputs; they can be used as Pwm generator to drive the ESC input?
That said, you should be able to drive an ESC with a PICAXE. I have seen a few times here that ESCs may have an arming sequence that needs to be performed everytime they are powered up. If so, you will need to find out what sequence would be required for your preferred ESC.
After a google search I’ve found this advice…To arm the ESC you need to provide 1ms wide pulses, which equates to minimum speed (2ms equates to maximum speed). The number of required pulses is unknown, but I’d suggest 10 to 50 pulses should work.
A typically radio control transmitter/receiver supplies pulses to the servos/ESC at approximately a 20 Hz rate or one pulse every 50 mS. For safety reasons, upon initial power-up, the ESC will not arm until it begins receiving pulses of approximately 1 mS width (lowest throttle setting=motor off). This is to prevent someone from being injured by turning on their transmitter with a throttle setting that would cause the motor to run instantly. On some model aircraft the propeller can cause serious bodily injury if this should occur when a hand or other body part is in close proximity.
As far as reversing the motor direction is concerned. Although many of the ESCs are somewhat user configurable for things like battery type, voltage cutoff and motor braking among other things. The ones that I have used in the past (Turnigy Basic, Turnigy Plush, Exceed and Castle Creations) do not have a reverse mode. To reverse the motor direction requires switching any two of the three phases going from the ESC to the Brushless Motor (the red, black, and yellow wires in the video). I am in no way an expert of these things, my experience with the ESCs comes from years of building and flying model airplanes. This does not mean that ESCs designed for cars could not have a reverse mode (I have no experience with these ESCs). But the one shown in the video is one of the type that I have used before.
