The speedometer is probably one of the gauges you spend the most time looking at. Here is some useful information about the GPS interface module:

When using the GPS module to drive your electric vehicle speedometer, the only time when you do not need to calibrate the speedometer is when you connect to a speedometer that has not been previously calibrated. In other words, when the speedometer and GPS module are both new packaging, no packaging is needed because they have been calibrated the same at the factory. If someone has tried to calibrate the speedometer or GPS module first, you need to calibrate the GPS module to the speedometer.

It is very easy to calibrate the GPS module to the speedometer. First, turn on the power, then press and hold the only button on the GPS module. After a few seconds, the needle on the speedometer will begin to climb. The longer the grip, the faster the climb speed. When the pointer on the speedometer reaches 80, stop holding it. We recommend stopping at around 70 and then using a series of momentary button presses. Finish now. It will time out after about 4 seconds and the pointer will return to zero.