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Servo on robotic arm causing power glitch

edited January 2017 in General
I made a PCB to control 6 servos (MK 996) on a robotic arm. The board also supplies two LCD/touch modules. The device is controlled by a Teensy 3.2. When I drive a couple servos the LCD panels blip. I believe that I need to add some capacitors to either or both servo bank and LCD panel bank. The power is 5V and I am supplying 5A. What size of capacitor(s) should I use and where?


  • You might want to measure the actual current draw on those servos. A quick search on the internet suggests that they might draw as much as 1.2 A peak, and if so, your power supply may not be sufficient-- even if you add some beefy capacitors.
  • Could I add capacitors and diodes to the LCD panels and the Teensy microcontroller so that they still have power and back flow would be hindered?
  • The 1.2A peak is the "stall current." I assume that the amount current draw is directly proportional to the load. However, your point is correct: I need to find out how much current is being used empirically.
  • If you can understand the reason for the dropout better, you'll likely understand what the right remedy is. Yes, adding extra capacitors near the power supply lines of touchy components is often helpful. But, your power supply likely has much larger capacitors on its output than you can add there. And, if it's dropping out for macroscopic amounts of time, capacitors won't help. I'm not sure what your diodes would be for.
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