I am new to Node-RED and programming in general so please bear with me. I am trying to replace a broken treadmill console Raspberry Pi 4 Model B and a touch screen. I would like to display and control everything in the node-Red-dashboard. I already have a few things working such as incline/decline and speed control.
I am needing some help with creating a speedometer gauge to display the belt speed in MPH. I have been able to view the speed pulses from the treadmill's tachometer line on my oscilloscope and manually calculate RPM based on the pulses and some physical measurements I have made. For testing purposes I am feeding the tachometer pulses into the GPIO Pin 4 through a two resistor voltage divider to reduce the voltage to 3.3 volts. Using a crude python script running on the PI I am able to detect the falling edge of the pulses so I am confident that electrically everything is working correctly.
I have been searching the Internet looking for something like this and have not been successful.
I am not sure how to create a flow to read the pulses and display the results in MPH as a round gauge.
Any advice or thoughts would be much appreciated.