Hi:
I am trying to read the servo’s single before, during, and after give a command.
I have a phidget interface kit 8/8/8 with voltage sensor. I want to know how should I connect the phidget interface kit with servo to get the data of singles?
I know it is not voltage. I know it should to do with pulse. But how do I get that data?
Thank you!
If we understand correctly, you want to measure the R/C PWM signal correct?
If that’s the case, we don’t think it can be done with a Phidget 8/8/8 device… The R/C PWM signal consists of a series of high-pulses with durations that vary between 500 and 2500 us (0.5 to 2.5 ms). The Phidget 8/8/8 on the other hand has debounce thresholds that require a low-pulse be at least 4 ms to be able to record a high-to-low state change, and at least 15 ms to record a low-to-high state change. Given these thresholds, it’s not possible to measure the R/C PWM signal directly.
Instead, we would recommend using a microcontroller with interrupts. There’s some sample code here that measures R/C PWM signals on pins D2-D5 on an Arduino:
Hope this helps,
Thank you very much for your helping!
What is your mean by R/C PWM signal? I have AL5 robotic arms. I am trying to measure the signals send from the SSC-32 Servo Controller to the arms.
For example, I have two AL5 robotic arms connected to a same SSC-32 Servo Controller. One arm is good and other arm has failure servos. Both arms will get same commanded from the SSC-32 servo controller. I want to measure the signal send from the SSC-32 Servo Controller to the arms. Therefore I can know the signals are same. Then I will compare the behaviors of two robotic arms to see how the failure servos affect the arm. Also I can find out the relationship between the signals and servo rotations.
In this case, how can I get the signal data? What kind tools do I need?
Yes, the signals sent from the SSC-32 board to the servos is R/C PWM signals. When you send a command to the SSC-32 board such as #1P1500, the SSC-32 board will then produce a repeating signal with 1500 microsecond pulses on channel 1 of the board. To measure these types of pulses, you can build a tool that uses the code above and outputs the values to the serial port.
If you have two arms, you can also try switching some parts to help troubleshoot the problem. For instance, if you’re having problems with base rotation, you can try swapping the connections for the two bases and see if it is the servo that’s the problem or the SSC-32 output channel. In our experience, it’s usually the servo…
Hope this helps,
