Wednesday, 28 September 2011

Full Kit

Here is a photo of a complete kit of parts for a UMT based Milestag gun.  Apart from the 20mm barrel, all parts have been printed with RepRap. I'm quite pleased with the results. I'm able to manufacture parts that, once printed, can be assembled into a functional device within an hour or so. long live RepRap!

This kit, and its Milestag Core brother are now availabale at

These parts come together to make this:

Sunday, 25 September 2011


I've recently completed a Mk4 version of my RepRap'ed Milestag lasertag gun. This version has a a serially driven 4 x 7 segment LED display to indicate health/ammo which I got from RoboSavvy. This is driven from my homemade Milestag UMT PCBs. These have turned out really well. The only issue that I had was the corrupted display I mentioned previously. Here is a Mk4 complete with DIY acrylic dome sensors:
This has my new style muzzle flash suppressor attached. This differs from previous models in that it has side slots to allow light to show through:

Saturday, 17 September 2011

All around my hat.....

When I made my first Reprap'ed Milestag gun I designed a small PCB to allow the IR sensors to be connected to the gun housing with a curly RJ10 lead. I initially fastened this PCB to the baseball cap by fastening them with tie-wraps. Hardly satisfactory.
I didn't advance on this rather crude method until now. I designed a small box to contain the PCB with mounting tabs to allow it to be fastened to the basball cap with press studs. It has two slots on the top and bottom halves for the PCB to slot into and some tabs for studs to be attached:
Here it is fitted to a cap. Much neater:

Monday, 12 September 2011

More domes

I've almost completed my Mk4 RepRap Milestag gun and I needed to make some sensor domes with mountings that allow me to fasten the sensors to a baseball cap. I started out by maing six more domes from acrylic sheet as detailed here. To do this I modified the dome mount I made some time ago. I needed to modify the dimensions slightly as my domes have an internal diameter slightly larger than the ones I got from Lasertagparts. Here are the two parts:
Rather than potting the PCB and dome in place, my design uses three screws to hold it in place. This allows it to be dismantled for maintenance.

Wednesday, 7 September 2011


I've been doing further assembly on my Milestag UMT PCB. I bought a serially driven 7 segment display module from Sparkfun. This module is the one recommended for use with the Milestag UMT board. It is used to display clip rounds remaining and life. However, I could not get the display to function correctly. I sometimes (about 80% of the time) got a corrupted display. I resorted to removing the PIC MPU from the PCB and wiring it up on a breadboard with just the display and run from a stabilised PSU. I still got the same results:
This should be displaying " 042". I made various attempts to fix it: Rewiring, shielded cable, more filtering caps, shorter sires. Nothing worked. I then noticed that when I picked the display up, it changed. I noted that this module has both SPI and TTL level serial inputs and when I touched the TTL input the display became corrupted. TTL level serial idles at logic 1, so I tied the serial input line high and I haven't seen any corruption since. The module accepts segment level commands. i.e. You can send 4 bytes of data representing the segments in each digit. Obviously the serial input was getting noise and this was being interpreted as a valid display command.