Rolling my own...

I'm fed up with paying silly money for ABS filament. I have two printers and it's getting expensive to keep them both fed. So I went and ordered a Filastruder. It is on its way as I type.....

Dome on the range part two.

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I make sensor domes for my Milestag guns using 2mm acrylic sheet heated in the oven and press formed over a mold using a 3d printed ring which is designed to fit over the mold. You can see the mold and the forming ring here:

The ring fits into an MDF sheet that allows me to push down enough force to deform the acrylic over the mold:

I wanted to experiment with polycarbonate sheet. It is cheaper and tougher than acrylic. However, it has a higher glass transition temperature (147C) than acrylic (107C) and this caused the ABS plastic of the forming ring to soften and leave deposits on the egde of the dome during the deformation process.

I decided to make a replacement forming ring from aluminium. I bought a billet from ebay for about £6.

I used a combination of drills and boring bars on the lathe to turn a replacement ring. It came out rather well:

It fits nicely into the MDF sheet and works slightly better than the ABS ring when forming the sheet as it has a narrower rim which allows me to apply more pressure to the sheet.

Safety Last

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My Milestag sniper rifle is coming along nicely. It has to be ready for the 22nd September when my son plans to use it at his lasertag party. The plan is to have two teams of 8 against a lone sniper.

I've added a couple of features to the rifle:

I've added a Barrett style muzzle brake:

And a mount for the RJ9 connector for the head sensors:

I've plumbed in the LS2020 laser module and this is working. This is going to be used at a commercial lasertag site, which uses Adventure Sports equipment. I have created a special version of my open source UMT code to be compatible with the AS protocol.

I've decided to play it safe with the LS2020 laser. Even though it is a class 1 device, I have modified the software to enable the PIC watchdog timer. The worst case Milestag packet length is around 27ms (all 1s). My software kicks the watchdog only in the 'turn the laser off' code which is called continuously unless a Milestag packet is being transmitted. The watchdog timeout is set to around 30ms and so if anything goes wrong and the laser is left on, the watchdog will reset the PIC and turn it off. So the laser will only ever be on for a maximum of 30ms.

The final step is to align the laser with the telescopic sight. To achieve this I've printed an adapter to allow me to attach a bullet camera to the telescopic sight:

And I've created a special version of the software that sends a Milestag packet every 500ms so I do not have to stand there pressing the trigger and reload buttons as I line up the sights.

Milestag sniper rifle wiring

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Now I am satisfied with with the LS2020 adjuster I've turned my attention to to the wiring. Using the worlds longest 10mm drill bit:

I drilled a hole along the axis of the stock:

Using some 3mm ABS filament as a pull through, I installed cables for the trigger, muzzle flash and IR laser:

Using picatinny rail mounts modified with holes in the appropriate places:

Finally I fitted the box to contain the electronics. This is mounted with a 3D printed rail mount:

Just need to add the electronics hardware.....

Laser diode adjuster: Third time lucky

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After 3D printing my Mk2 LS2020 laser diode adjuster I decided that it could be improved. I managed to reduce the height by about 20mm and improve rigidity. Here is the new design:

Here it is fitted to the sniper rifle body, note that the wooden stock is now stained:

From the top it is noticeably slimmer than the previous version:

Laser Adjuster Fitted

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I fitted the LS2020 laser adjuster to my Milestag sniper rifle after printing and fitting a picatinny mounting clamp. It looks good, but it sticks out too far. I've had a few ideas for a Mk3.

Second Sight

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After designing a windage/elevation moubnt for the LS2020 laser diode, I realised that there would be too great a moment if the laser was twisted. So I redesigned the entire thing and came up with this:

It has an arm which rotates around an M4 screw. This is held in position by a long M4 bolt which engages in a 'V' indentation in the outer circumference of the arm. This screw acts as a worm drive and allows accurate positioning for the elevation.
The windage adjustment mounts on the arm, and uses a pair of hinged plates. These are moved together/apart by an M3 screw threaded into a brass bar embedded in the lower plate. This has some rotation as the angle of the M3 screw changes as adjustments are made.

Here it is in the real world, the LS2020 module is just visible.

The elevation adjustment screw can be seen in the centre of the plate with six screws: