The Pico Oscilloscope RoadTest Review is currently in a holding pattern due to a shipping error. I figured I would fill the wait time by sharing the methodology or my approach for the RoadTest. I value the input from members. On past RoadTest their commentary has improved my review by providing knowledge I didn't have, thereby enabling me to correct details I stated in error.

 

My application offered to review the equipment while analyzing servo motor operation. Recently, I discovered a tutorial I wrote in June 2019, demonstrating servo motors on a Raspberry Pi, doesn't work today. My preliminary investigation of the servo problem was interrupted by "SQUIRREL" https://www.youtube.com/watch?v=SSUXXzN26zg .  The RoadTest Review of the oscilloscope was an opportunity I felt would force me to focus on the task at hand. Why are the servo motors not working on the Pi?

 

It appears the endorsement for operating servo motors is higher on microcontroller like an Arduino rather than on a single board computer (SBC) like the Pi. Raspberry Pi's are running an operating system that shares the signalling of the servo with a host of other tasks the operating system is managing. The multitasking environment impacts the servo's performance. I plan to analyze the servo motor signals using the Pico oscilloscope to uncover the knowledge that will hopefully improve my understanding.

 

I'm initially looking at three areas that influence the servo operation. Microcontroller vs SBC. The servo motors themselves. How the signal are generated through code.

  • The test platforms that will generate the servo signals will be a Raspberry Pi3B+ GPIO outputs and GPIO's on an OEM Arduino Nano.
  • The servos being used are Tower Pro SG92R & SR90.
  • The code will be python on the Pi and C++ on the Arduino. I suspect the signals themselves produced by the Pi or Arduino are impacted by the code solution. i.e. using a defined method or producing the signal raw. This is an area of particular interest. I will give it my best shot. Unfortunately, I lack the programming background to fully investigate.

 

I confess my testing methodology is not consistent i.e. not using same code on both devices. If I step back and not get buried in the weeds, my goal is to evaluate the Pico 6424E Oscilloscope and not write a research paper on the operation of servo motor. If that was the task I would reserve it for more talented people in this community than me.

 

Here is what I have for code solutions to operate a servo motor.

Raspberry Pi:

  • RPi.gpio
  • gpiozero
  • wiringpi

 

Arduino:

  • Servo.h
  • manual define servoPin 9........

 

A question to members: what code solutions are you using to control servo's?

 

To reiterate, the goal is to review the Pico 6424E Oscilloscope. The devices are being used just to produce the signals for the scope. I may not arrive at an answer to my problem but I am confident the equipment will enable me to at least look at the signals.

 

The review needs to include both analogue (probe) and digital (MSO) capabilities of the oscilloscope. My experience using oscilloscope stopped in the mid 90's when my career moved from electronic support to computer support. I have some challenges in blowing off the accumulated dust on the knowledge I have as well as the changes in technology in twenty years.