Pulse Motors: SNOT Update 2: Arduino Data Display of Velocity and Energy
Here’s another SNOT update. This time I’ve cobbled together an Arduino data collection system.
The Arduino monitors the gate signal from the SNOT controller circuit by the use of the pulseIn() function on pin 4. The loop time is calculated using the millisec() timer from the beginning of one pulse to the beginning of the next one, and the velocity v is calculated by dividing the track circumference 0.85 m by the loop time in seconds. Then the KE of the 0.016 kg ball is calculated by KE = m * v * v * 0.5, and the result expressed in microJoules. The sketch performs this calculation on every tenth loop.
Now I have a very good idea of the actual power dissipation of the SNOT ball on its track. I’m not going to tell what the input power to the electromagnet is though… not yet anyway!!
The Parallax brand LCD only uses a single wire for data, and power and ground. Very easy to use with the Arduino, if a bit limited in size. You only get 2 lines x16 chars, but it handles all regular chars and you can construct your own special characters too. It also has a speaker and can do the usual tinny tunes, alarm beeps or whatever you send it.