I am trying to make a "laser gun range" like the ones you see at carnivals for my embedded systems class at school. However, I am having trouble because I do not know how to construct the "target". I want to be able to point a "gun" at a target ranging from 4cm to 0.5cm in radius, and I do not know how to detect a laser pointer over that range. CdS photoresistors are very small. I have also looked at IR but as far as I know you cannot focus it. I need help in coming up with a detection method. Bonus points if I can detect whether someone hits the center or edge. If necessary, I can also switch to mechanical Nerf gun range, but then I have to come up with a target with moving parts and have to detect how many bullets were shot and if the target is down somehow.

EDIT: I found the exact product I want in that it can detect laser shots but I have no idea how it works. http://www.youtube.com/watch?feature=player_embedded&v=q9_qMxHj0Mw

Background: The focus of the course is "the correct way" to write programs that run on small microcontrollers using state machines. For the end project we have to create a game that uses an 2x20 character LCD, a 16-button keypad, an LED, a button, a speaker, and a seven-segment display all on an ATmega32, which shares a similar peripheral set with the Arduino. I can even use an Arduino Mega with the condition that I write all code myself. (no Arduino.h) I know how to use all these devices and shift registers to give me more I/O. I just need an idea to implement.


The 'Laser' target systems that I know use IR for hitting the target. The gun is a variation on the TV remote, with a lense to focus the IR. Yes, you can focus IR just fine. Or use a LED that has a narrow beam by itself. The target uses an IR detector module, like a TSOP1738 or a newer variant.

The laser is only for the spectacle. (Indoors they use mist machines to make the laser vissible, outdoor systems often don't use a laser at all).

A this very moment 10 student groups are developing the firmware for 'laser' tags for me for a course in 'embedded systems programming'.

For a suggestion on what to implement you can read any website that talks about sending and/or receiving IR control signals. No need to use a specific one, as you make both the sender and the receiver.

  • \$\begingroup\$ Interesting. I thought that the TSOP1738 catches light in all directions, but I have never tried using a focused IR LED. \$\endgroup\$ – Andrew May 18 '12 at 12:37
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    \$\begingroup\$ @Andrew: The receivers need to be omni-directional since they don't know from where a shot is coming from. It's the senders that should be narrowly focused. \$\endgroup\$ – Olin Lathrop May 18 '12 at 12:50
  • \$\begingroup\$ @Wouter, is one of your students named Andrew? \$\endgroup\$ – The Photon May 18 '12 at 15:28
  • \$\begingroup\$ No, I would have noticed, and the specs are different: lpc2148, C++, and a mandatory development method and rtos-library. And we provide the hardware, and a prototype 'gun', and explain how IR works. \$\endgroup\$ – Wouter van Ooijen May 18 '12 at 19:43

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