Set up TAC with Start and Stop both from emitter to make sure it was working and to check the delay.
got 1.34 volts for 10 ft of cable about 1.34 ns for delay time in cable.
Reconnected Start from emitter, Start to detector
for initial test Readings 1st stick reading 75cm 3.8V => 38ns
2nd stick reading 95cm 3.7V => 37ns
3rd stick reading 55cm 3.9V => 39ns
over 40nm get 2ns difference giving speed of light as .4m/2x10^-9s=2x10^8m/s (+/-1x10^8)
4th Stick reading 55cm PM ->-.8V 2.16V => 21.6ns
5th stick reading 80cm pm ->-.8v 1.98V +/-.02 =>19.8ns
speed of light from 4th to 5th .25m/1.8x10^-9s = 1.4x10^8m/s off by a factor of 2
6th stick reading 105cm 1.84V => 18.4ns
speed of light from 5th to 6th.25m/1.4x10^-9s = 1.8x10^8
Error because of reflection? or other.