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01-03-2019, 10:52 PM
Reminder: The ground bus is used as a reference baseline for all of the communications between the Arduino and the Simple Motor Controllers (SMCs), and also between the Motor Controllers and the R/C Receiver. They should all be connected with a common ground.
Similarly, the Simple Motor Controllers all get their positive power from their 12V input and regulator, so they don't need a + power connected. DO NOT connect their +5V lines together or their regulators will all get in an argument and probably bad things might happen.
The Arduino can also use it's own internal regulator *or* you could steal the regulated output from one of the SMC's to the Arduino for it's 5V power. If you're using the Arduino's regulator, then DO NOT connect the Arduino +5V output to any of the SMC's 5V lines, they'd also get grumpy.
The R/C receiver, however, does need power from somewhere. And from exactly ONE somewhere at that. In R/C terminology they call that a "BEC" (Battery eliminator circuit - eg: get power from somewhere else so that the Receiver doesn't need it's own battery). Since we're connecting the servo lines from the R/C receiver to the SMC's anyway, the easiest way to power the R/C receiver is from ONLY ONE of the Pololu Simple Motor Controllers.
Fortunately the SMC's have a "BEC" connector. You need to connect the "BEC" line to the 5V line on one SMC. That'll provide power through the servo wire to the receiver. (I realize the receivers probably also have a power input, but mine are all connected internally, so all the + are common on the RX side, as are all the - wires).
FWIW: RC Servos have 3 wires: Two are + & - to provide power to the servo. And the 3rd wire is the signal. If our receiver didn't need power, we'd only need the - and signal lines since our SMC's are self-powered. But, as mentioned above, ONE of the lines needs to provide power to the receiver.
Similarly, the Simple Motor Controllers all get their positive power from their 12V input and regulator, so they don't need a + power connected. DO NOT connect their +5V lines together or their regulators will all get in an argument and probably bad things might happen.
The Arduino can also use it's own internal regulator *or* you could steal the regulated output from one of the SMC's to the Arduino for it's 5V power. If you're using the Arduino's regulator, then DO NOT connect the Arduino +5V output to any of the SMC's 5V lines, they'd also get grumpy.
The R/C receiver, however, does need power from somewhere. And from exactly ONE somewhere at that. In R/C terminology they call that a "BEC" (Battery eliminator circuit - eg: get power from somewhere else so that the Receiver doesn't need it's own battery). Since we're connecting the servo lines from the R/C receiver to the SMC's anyway, the easiest way to power the R/C receiver is from ONLY ONE of the Pololu Simple Motor Controllers.
Fortunately the SMC's have a "BEC" connector. You need to connect the "BEC" line to the 5V line on one SMC. That'll provide power through the servo wire to the receiver. (I realize the receivers probably also have a power input, but mine are all connected internally, so all the + are common on the RX side, as are all the - wires).
FWIW: RC Servos have 3 wires: Two are + & - to provide power to the servo. And the 3rd wire is the signal. If our receiver didn't need power, we'd only need the - and signal lines since our SMC's are self-powered. But, as mentioned above, ONE of the lines needs to provide power to the receiver.