To be honest, this feature is not necessary but I put it in because I can. The four LEDs in the Top Panel PCB can run on its own or, sync with the Front Array PCB. You need a soldering iron to make the change, which is to solder a link on the jumpers. You will also need to solder the other end of the wire to the clock signal on the Front Array. Alternatively, I guess I can design a SMD slide switch in there and also solder the Clock wire. But there are two 555 clock sources on the Front Array PCB, which you have to choose. I can design another slide switch there too, since the two 555 IC would also have its own variable resistors.
To be honest, it would not make any difference, except to the person who is building the Tricorder. Ha ha.
SWITCHING TO EXTERNAL CLOCK PULSE
Here is the step by step on how to use the clock pulse from the Front Array PCB.
Remove the solder link from the on-board 555 IC and solder the link to the CLOCK
Locate the Pin #3 of either 555 ICs and solder the pin. The slower 555 is for the lower Amber scanning array. The faster 555 is for the Green middle scanning array.
THE VIDEO
You know, i think the Video would explain it better. My fingers are tired.
