Smaller on the inside

At a loose end this afternoon I stumbled across this old airsoft machine pistol I bought way back in the summer, thinking to use as the basis of a Lasertag gun. I've tons I should be doing but stripping this down and messing about was what appealed.

It's not a bad looking thing and the clip over folding stock is really quite cool. Visually it's kind of like a mini-Uzi with a bit of Kalashnikov DNA.

The whole thing is quite small, so it's going to be a bit of a challenge to make it into a working Lasertag gun. Thankfully though, the emitter assembly I bought looks a good fit to replace the current barrel.

The diameter is very similar so it's not going to mess up the look of the gun and should mean is going to be an easy fit.

With a tiny bit of messing, the emitter directly replaces the barrel. It protrudes further from the front of the body but I may able to slide it back somewhat. I've not done that just yet as one of the locating lugs for the body is in the way and I don't want to remove it. If the barrel looks OK like this I'll leave it. My only worry is it may not be desperately secure given how far it sticks out.

So here is a very rough mockup of how I might mount the components. Obviously missing right now is a speaker or sound board. The latter I can easily fit in, but the speaker is going to be very hard. I've got a couple of small ones but they're still far too big.

No chance of fitting the muzzle flash LED inside the emitter as I've bought it complete. It'll have to be somewhere on the front face of the gun, but this shouldn't be hard to pull off.

I need to buy some NiMH batteries to turn into a 7.2V brick. The 3.6V Li-ion ones you get are appealing but more complicated to charge so ideally need to be removable.

I also need to buy an assortment of switches as I've nothing but little PCB tactile stuff at the moment. This will need a power switch, reload switch and trigger. I've a half formed plan to use reed switches but it might not work out.

The Lasertag gun I bought made up by Phil was constructed out of a Playstation Time Crisis style light gun and I can see why. You get something already designed to emit IR with a switch at the trigger and a smattering of other buttons.

Back to the future

Not for the first time my parents have provided me with LARP kit. Months ago they asked me if I wanted this old plastic coolbox and I sensibly declined.

Now, with a Blake's 7 LARP coming up I remembered the offer and picked it up from them. On numerous occasions, particularly in series 1 & 2, it looks like the B7 crew use a large plastic coolbox as luggage.

A combination of aluminium foil tape and clashing yellow tape has given me something that looks late 70s futuristic.

OK, so the box in B7 is generally red, but this is LARP not cosplay.

Over the next few weeks I will attempt to fill it with a bunch of weird probe type tools like those Vila and Avon used. I'm, playing a technician type character and want to have some bits to play with in game. I reckon crocodile test leads, multimeter, a few things with flashing lights on etc. will work nicely.

Laser-Tag sensor prototyping

The flipside of making my own Laser-Tag gun is I also want to make my own sensors.

Phil Higgins makes a sensor designed to be worn on the head which is accepted to reliably take hits outdoors and has all the 'data over tag' stuff coded in by him already. Loads of people in the group I play with use these and I can't see myself replacing mine with something of my own devising.

However I do want to make a 'target' for testing Laser-Tag guns against and maybe some props that can be shot as part of broader functionality. So tonight I messed about with a simple test rig of an IR detector wired up to an Arduino with an Interrupt Service Routine attached to the relevant pin.

Laser-Tag uses a 56Khz carrier signal which is slightly different from typical IR remote controls, but there's a recommended component for putting in the sensors: a Vishay TSOP34156. This filters out the carrier signal and background noise from ambient light, leaving you with a microcontroller compatible output of just the encoded signal.

So far so simple, I now have a simple sketch that will flash a light and play a tone when I shoot the sensor. It's not really matching the Laser-Tag signal, just counting pulses and registering a hit if it gets enough in a short period. One of my remote controls sets it off.

This is something I can work on. For now though, tonight's fiddling has shown me that building a target shouldn't be hard. So I can start making the case etc. and then hone the code once it's in a usable shape.

Scribe in a box

Digging out a bit of an oldie here, I got reminded of it as I was copying files off.

This is the 'Scribe in a box'. I play in a fantasy LARP and there's a bit of politics and the occasional episode of NPC plot exposition. Just like meetings in real life, things get forgotten if you don't take minutes.

Nobody really wants to do this and my partner found herself spending time frantically scribbling stuff down rather than enjoying herself. This was my solution.

It's a cheapo digital audio recorder from eBay, chopped around and stuck into an in character looking box. I extended the controls by carefully soldering wires to the little circuit board where the nasty metal diaphragm buttons were. I connected these up to proper switches and put coloured rhinestones on top so you could tell what they do. Likewise I fitted a decent battery holder and the AAs in there will run it for ages.

If you peer into the perforated top you can just read the original LCD display but in practice it's red button to record, green to play and when it's running you can see the little red light glowing.

This has proved very useful and is a fixture at our games now, with the recordings getting written up after the event. The only thing that is fiddly is that to get the recordings off I have to tease it apart and slide a USB cable into a socket hidden in the rat's nest of fragile switch wiring. The temptation to fix this is tempered by a worry about spoiling the look of the thing as it's really quite a nice little wooden box.

Did I fire five or did I fire six?

I have a working Lasertag gun! I tested the emitter wiring, found it was fine then realised I had a stupid error in my code. I've taken the Lasertag shot code Phil Higgins gave me and stuck some very basic stuff round it to make it fire with the trigger, run out of ammo and do a reload sequence. While doing some cutting and pasting I'd simply left a line out.

The gun is cosmetically a bit dodgy where I've fitted the power switch but it does work, at least indoors. Things obviously left to do are fit the sound board and speaker then if at all possible fit a USB lead so that it can be reprogrammed without taking it to bits. The LEDs on the Arduino itself are bright enough to see through the holes in the case already and act as status indicators so I don't think I need a separate one.

I want to work on the code and ideally make something interrupt based for generating the shots, but right now this will do.

The Internet of Things revolution is coming

I got my new Arduino, yay! Soon you'll be able to see whether the condensate reservoir in my cellar is emptying or not and check out the nice stable temperature all year round.

Inconceivable!

Last thing to do is mount the stack of boards in a box to keep the dust off but I've not found anything suitable. I'm using up an Ethernet shield and screw shield that I have kicking around, neither of which I can see myself using for anything else. Stacked up they make the thing quite ridiculously bulky for what it does. So it's all just going to have to get stuffed into a big box. It's not like it's going to be on show, it'll be sitting in the cellar.

It's my party and I'll solder if I want to

Today's my birthday and I didn't have anything planned so I had a soldering party instead.

I love this stuff so frankly spending a night in messing about doing this accompanied by a pizza and a couple of beers is a pretty good evening in my book.

The end result is my first ever Lasertag gun board.  I imagine it's blooming enormous compared to the PIC based ones as I've got an Arduino in there and it's all socketed up on 0.1" headers. This is deliberately done so I can mess about with it and use it as a bit of a testbed. It's been made so it nicely fills the empty space in the middle of the gun.

For power in the end I used a tiny little step-up switched mode voltage converter. Easier than messing around with funny Li-ion batteries or trying to squeeze five AAAs in there, but obviously it's not going to have brilliant battery life.

I've got the trigger and reload switches wired up, a muzzle flash working and a space for the sound board, which I'll fit another evening. It's the same WTV020SD module I've used in a couple of other projects so I'm sure it'll work OK.

Right now sadly this goes through the motions but doesn't cause Lasertag hits. It's probably just a stupid wiring error as I've used the code that's worked fine in testing and I'll debug this tomorrow night.

The Internet of Uninteresting Things

You are looking at my addition to the Internet of Things. Well it will be once I get a new Arduino to replace the one I shorted out in a moment of hamfistedness.

All the code is written and it works but is suitably ugly, just need to wait for the new board.

It's a self emptying condensate tank for my dehumidifier with temperature and humidity monitoring. Are you excited yet? I'll be sure to provide continuous updates for everybody.