I am running everything from the board's power supply (which I know is a no-no)
but I couldn't get a response when I used a 9v battery with a voltage divider as an external 4.5V power supply.
A 9v smoke detector battery? Also not a proper power supply.Try 4x AA batteries to power the servos. Use common ground.
That's why I tried creating a voltage divider: Vout = [R2/(R1+R2)]*VinWith, my Vin as 9v and R1=R2=10kOhms, it should be 4.5 V, or roughly 3x AA batteriesIt's just your garden variety 9V battery. Im sure you could use it in most smoke detectors.
Yes, you can use it in a smoke detector or a transistor radio. Those applications pull a VERY small amount of current.Your physical motors do not pull such a small current. They pull a much larger amount of current and the 9v battery cannot provide that voltage at that current. The voltage drops way down and your devices brown out and fail.
. A 4.5V external power supply was created using a voltage divider from a 9v battery. this Vout of 4.5V ultimately provided no response so it was not used. again, the boards power supply is what the schematic indicates as well as what the scope output.