Scrimming: No, not the gaming sort...

 Scrimming in this context refers to the art of concealing your self using fabric pieces and, in the case of field work, vegetation to enhance your concealment. I don't currently have a proper stock for my Tempus so my old Stryfe Raider stock is going to have to do until I can arrange an alternative. The problem is that it's bright bloody red! That's fine if you're running around a sub-130FPS field but Invicta Battlegrounds is a forest with a side-helping of forest. Blending in and trying not to get tagged is the name of the game.

To the red/green colour blind, that might not seem like too much of an issue but to me it's both shiny and bright red.

I cut up and old scrim scarf into chunks of fabric to be used to cover the back end of the stock. Nature has no straight lines and shiny things catch the human eye to movement as light reflects off them. The softer lines of the dull fabric make concealment much easier.

Cut up some lengths of shock cord to act as anchor points for the scrim net.

Tie them into position to create some anchor points.

I'm not entirely sure it worked. The end effect is there but I think a different approach might be useful. Scrimming is always an ongoing process so I guess I can fettle and work to improve it. We'll see if it works at the weekend on the field.

[WIP] Open Source Nerf PCBs are coming!

 I've been in the Nerf PCB game since at least 2016 developing the BritNerf MOSFET board as well as a board for the Stampede when I was with Blastersmiths. Back before the plague, I published a bunch of free to use board files but with real life and the pandemic, progress has stalled.

I've been working on them on and off again since April of this year on a range of boards. With the development of dual stage flywheel systems, I found wiring everything close in on the back of a printed cage and getting it all correct was a very frustrating exercise. To that end, I created a dual stage MOSFET flywheel board compatible with the Gryphon and Tempus when used with Daybreak flywheels.

This is the progress of the dual stage board from first concept through to the latest version at the time of writing (v0.5). It started originally as a single FET version but I quickly realised the utility of two MOSFETs, one for each pair of motors. I'm doing a lot of background work on different motor combinations for dual stage and some of the big 132 and 180 can motors draw a lot of current. By having multiple FETs, you're not stressing a single component past it's limit and it probably will work out cheaper to install. The latest version can be powered from either end after I discovered the need for that feature in the Tempus.

v0.4 testing rig, note the lack of forward contacts in this version

Testing these systems is fairly easy, you just chuck some motors into a printed cage and drop the board on the back back. Solder in a switch and an XT 60 plug and you're good to go. The obvious draw back here is the need for all the cans to be the same length. That certainly isn't the case in my current generation of Tempus build so there needs to be a solution for that.

Enter my MOSFET motor span board. The most recent version also has expansion connectors at the front to allow for daisy chaining boards forward. It is then possible to hook up a simple motor span board (see below) for dual stage motor systems with different can sizes. It might also be possible to link the trigger pins of two boards together and use the expansion slots at the front to link two MOSFET boards but I've not tried that yet.

The problem with extant motor MOSFET boards is they use smaller packages than really are ideal. Nerf motors draw a lot of current and even if the silicon in your MOSFET can handle theoretically high currents, the package it's in might not. For example, my go to N-channel FET is a IRLB3034 which, on paper, has a maximum current of 343A. The problem is that the TO-220 package it's mounted in is rated to 195A. That's still a lot of current but it can handle that because it has a giant heat sinking tab in addition to a much physically larger package for dumping heat out of. Smaller packages don't have that luxury and are prone to failure. Yes, it might look pretty to have a small SMT package with neat flashing LEDs but through hole technology means you get a durable, rugged board that won't fail. The BritNerf MOSFET board has been in circulation for years and is a reliable, dependable platform. I guess my HvZ heritage shows here: stuff cannot fail because the cost of a single failure is absolute. But that's a story for another discussion...

Itty bitty FTW motor board

And for all those FTW fans out there, these boards are a simpler way to install motors into an FTW build. I have a Grass snake powered by Krakens that are going to get one of these because it's a mess in there and it needs tidying!

 

Not everything goes to plan, however. There's an inconsistent bug in this one particular board and I need to properly hunt it down. Even though it uses the same library component as everything else, the Gerber files don't always produce a slot and often create a hole instead. This is the more traditional motor span board with an optional XT60 connector and input/output solder pads for daisy chaining multiple stages or just having powered supplied to one end of the board rather than the other. Oh and it has a diode mounting position because some folks have requested the ability to have an 'after-glow' effect that uses the back-EMF of the motors as they spin down. So that's neat...

I've run out of FETs and diodes so I'll have to wait for those to arrive before I can test those boards. In the mean time, I'll get the FTW  board tested and probably strip out the front of the Tempus ahead of mounting those boards. In particular, I'm going to go back to the circuit diagram and see if I can daisy chain those single stage FET span boards.

Once all these files are ready, I will publish working Gerber files as well as the EAGLE files on my GitHub on a Creative Commons 0 or Public Domain license for folks to do whatever they want with them for free. I've already got a distributor ready to go for these and I think a few more are coming on board. However, if folks feel they want to order from JLC PCB or another fab house directly then they can just feed the Gerber files without need to pay a license fee to me to get their boards made and posted direct to them. Open source is best source.

BOLLE Tracker Goggles Update

 Sometimes projects take a while. Well, this case it's only been 6 years in the making. Back in 2015, I reviewed my current eye protection of choice: the BOLLE Tracker specs with yellow shooter lenses. They're great insofar as they're wrap around and with the elastic band, they hold in place even during the roughest combat.

I commented at the time that the white and black logo strap was a bit much and I needed to do something about it. It's only taken 6 years but I got around to it this weekend while preparing for Invicta Battlegrounds on 18th September.

I took a scrap of DPM cotton drill fabric and measured 3 times the width of the strap and double the length. Capping each end with a 15mm seam and then sewing it camo side to camo side, I could turn it inside out and produce a nice cover.

The main problem was that back in the day, I glued the strap in place. In order to get the cover onto the strap, I unpicked the factory stitching, threaded on the cover and replaced it with a few stitches from my #60 nylon thread which is probably tougher than the OG stuff.

I've washed the lenses thoroughly and added a layer of dish soap over the top in an effort to stop them from fogging. They're good lenses but I'm worried the amount of scratches from wear and tear is starting to provide focal poitns for moisture to start fogging. If this doesn't work, I'll replace them. I can't really get on with mesh, it darkens the field of view too much while causing glare in bright sunlight conditions. The UV proof coating of the Trackers is also a value added feature.

I'm on leave this week so between sewing BoffTac orders, preparing for Invicta on Saturday, I'll probably see about documenting some stuff around a 130FPS blaster I'm working on and designing some kit for my first indoor war in 18 months.