Rear sensors:

Well finally got around to some serious research on adding rear sensors to the Lock-On system. I spent a bit of time creating schematic diagrams of the gun and headset circuit and as a result were able to get a really good idea on how it all operates. Best of all I found out about a lot of the components used and the similarities between this and other lasertag systems.

The Lock-On headset uses a PH310 PIN photo diode which is the same as ESS and many IR remote control applications. An equivalent version is the PN323B made by panasonic, all you need to do is wire one of these in parallel to the existing diode. Tests so far have put the range from front and rear at 60m. This is certainly acceptable and will make a huge difference to the game

I have mounted the photo diode in a small plastic case and cut a slot at each end for the 25mm headband elastic to thread through. Curly cord is used to connect the plastic case to the headset. Small notches are cut into the headset case to allow entry of the curly cord, here it is soldered directly to the legs of the original diode.

On to the instructions: CLICK HERE

PN323B photo diode - Datasheet

PH310 photo diode - Datasheet

GL3274 IR preamp - Datasheet                      (equivalent to the SONY CX20106A)

First prototype rear sensor.

A 2 litre ice-cream container makes a good test head!

Schematic of headset