You can use the timer by powering the Feather through USB or using a Lithium Ion battery.
Once the car goes past both sensors the speed will be displayed. I did not have another track piece to connect to the left side. But both sides are compatible with Hot Wheels tracks.
If nothing is displaying verify that the display is not too tight to the enclosure causing the reset button to be held in.
I designed the timer to fit taller vehicles but some are too wide for the track and will not fit. This vehicle was an example, it was just a bit too wide.
