At risk of asking a stupid question; is any servo compatible with Arduino? (I need a 360 degree servo for a project I’m working on but don’t want to wait for the sparkfun servos to be back in stock) If not, it there a way to tell if a servo is compatible?
A cheap regular servo will work. Suggest to get an analog servo instead of digital, there just easier for beginners.
The issue might be in identifying the PWM signal wire, in the triple of wires. Different brands use different connectors iirc. But maybe they organized some standard over the years.
Thanks, Two follow up questions.
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How can I tell if a servo is digital or analog?
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What is a PWM signal wire?
The receivers in RC models send out a voltage pulse about every 20 miliseconds over one of the 3 wires to the servo. Technically this is a digital signal, but the circuitry inside the analog servo processes this in an analog way. The other 2 wires are supply voltage and ground. The length of this pulse defines the angle to which the servo tries to rotate. 1 milisecond length means fully counterclockwise, 2 milisecond means fully clockwise. Centered is supposed to be 1.5 milisecond. So this is a pulse-width-modulated signal (PWM). Though when PWM is used in the context of microcontrollers or other electronics it is usually a more frequent repetition of pulses, where the on- versus off-time defines how much the signal is ‘‘partially on’’, or somewhere between 0 and 100%. The RC servo signals have long periods periods where no pulse is present. (20 milisecond - 2 milisecond) Also the repetition period for RC servo’s is not realy fixed, so it’s not quite standard PWM.
Digital servo’s have microcontrollers in them or more accurate crystal/resonator controlled circuits in them that do more advanced processing on the signal before controlling the motor. Also some can be communicated with through some sort of digital protocol, for which they might have extra wires. Either way, if the documentation doesn’t say it does fancy digital stuff inside (like PID controll-loop) then it is of the analog sort. And if it is digital it probably works anyway to be downwards compatible with old fashioned RC receivers.
Cool, Thanks
-CG