For those enthusiasts of "old-school" Lazer Tag, as well as for the clubs and players who have a lot of money invested in Worlds Of Wonder ("WoW") or compatible gear such as Electronic Survivor Shot ("ESS"), there is a hidden WoW compatability mode in the IRT-2X "Drone" and Tag Master Blaster models.
This mode is accessed by scrolling to "QUIT" on the main menu, then pressing 2ndF five times, then pressing OK. You are then presented with six modes to choose from:
SPRO -- Starlyte Pro Rifle (Fire only, Single-shot or Burst)
SLSN -- Starlyte with Sensor, Normal lighting
SPSN -- Starlyte Pro with Sensor, Normal lighting
SLSB -- Starlyte with Sensor, Bright lighting
SPSB -- Starlyte Pro with Sensor, Bright lighting
You can scroll to the mode desired and press OK for the default configuration (6 hits in the modes with Sensors), or scroll to the desired mode and press 2ndF+OK to enter a menu in which you adjust the hits from 1-99 (only for modes with Sensors -- and press OK when done). In the Starlyte Pro modes, the SHIELD button toggles back and forth between single-shot (one tag launched for each pull of the trigger) and automatic firing (holding the trigger fires up to 40 tags in a row before it must be released), making a distinct sound effect for each.
All of the modes mimic very closely the shot-to-shot, hit-to-hit, and cool-down timing of the original WOW gear. They do NOT mimic the "stun" effect of the ESS equipment, in which a player who was tagged could not fire for a short time.
In the modes with sensor function enabled, the Tagger will no longer fire after the sensor has been tagged out. This is different from the original WOW gear, in which the sensor was not directly connected to the gun and therefore the gun could still fire after the sensor had been tagged out (it is more like ESS in that regard).
Pressing the INC or DEC buttons will toggle between two display screens, one of which shows the model and number of hits remaining ("SPSN 6" for example), while the other shows the elapsed game time. After being tagged out, these buttons toggle between elapsed game time and survival time, but in the IRT-2X this has a bug in which the survival time accumulates across games, rather than being reset at the start of each game (the TMB handles this display properly).
The Problem:
Unfortunately, in the IRT-2X "Drone" this hidden mode had a problem with taking self-hits when fired, making it almost useless. The good news is, if you don't play games with mixed gear (old WOW or ESS gear and new LTTO gear in the same game), you don't need to worry about it -- none of the Drone's regular LTTO modes are affected by the problem. The bad news is, if you DO like to play mixed-gear games, you need to make some modifications to your IRT-2X "Drone" Taggers before you can use them this way.
The hidden WOW compatability mode in the Tag Master Blasters is not affected by this problem, it works properly without any modifications needed.
What is happening:
The problem is caused by noise and interference that were introduced to the receiver circuit when the layouts and wiring were changed between the time I developed the mode on the prototypes and the time we went into production with the final design. The problem can be a very minor annoyance or a major problem, depending on the particular unit and the lighting conditions.
Several problems are combining to produce the self-hits. Firstly, the electromagnetic radiation from the speaker is being picked up by the coil in the receiver. This coil just so happens to "ring" (self-osciallate) at the carrier frequency AND the data frequency of the WoW signal -- 57 KHz and 1.8KHz respectively. Because the firing sound has a noise component that is close to 2 KHz, the coil picks this up and generates what ALMOST look like real WoW mode signals coming into the receiver. In addition to this problem, the wiring needed for the LTTO native modes also brings up some energy right at the carrier frequency of the WoW signal, so the receiver is always "right on the edge" of detecting a signal to begin with. And finally, the sudden variation of the supply voltage due to the high-current demends of generating IR and sound effects causes the receiver to become just slightly unstable for the few milliseconds right after the IR transmission ends.
All of these things combine to make the receiver THINK it is seeing a signal from the outside world, and the output from that receiver ends up looking close enough to the WoW signal for my CPU code to beleive a signal has been received, so it takes a hit.
What can be done about it:
The most effective approach I have found so far is to replace the original LTTO coil (which was too prone to picking up interference) with a shielded or toroid-shaped inductor, and eliminating the 57-KHz carrier frequency which is coming up the wiring to the receiver.
I did have extremely good luck with a home-wound toroid inductor (260 turns of 30-guage enamelled magnet wire on an Amidon FT-50A-J core), but this takes an hour or more to wind by hand, so I set out to find a better solution.
What I came up with is the Toko 181LY-124J shielded coil, available from Digi-Key as part number TK4426-ND. Unfortunately, as this coil is only 120 mH and we need 200 mH or more, this mod requires two of them:
I assemble them by first hot-melting two side-by-side, then soldering them into a series configuration as shown. I also add short "lead extenders" as the leads are not quite long enough (I make these from 1/4 watt resistor leads). Note that the far right-hand lead is then bent back so it comes up between the leads of the nearest coil. This is so that it can solder directly into the dome receiver PCB, keeping the leads very short. No long wires means less interference being picked up, which is a good thing!
With this built, I then unsolder the existing coil from the dome (remove the leads from the coil end also, otherwise they just dangle around and short things out), making sure to solder-suck or solder-wick the holes in the PCB so that the new leads can fit into them easily.
I then apply a small ammount of hot-melt glue near the rear of the coils and let it cool. This will hold them in position while I solder the leads into the PCB.
Now, using a heat-sink clamp or set of hemostats, I solder the new leads into the old holes in the PCB where the old coil wires used to connect. This should be done quickly and with a steady hand and fine soldering iron tip so that you don't desolder the extender leads or create solder-shorts on the PCB.
When all is done, I add more hot-melt glue to hold the thing all steady in its place:
Remember to leave the "extender leads" long enough that the coil will clear the forward screw post once the dome is reinstalled into the plastic (see picture below).
The next step is to eliminate the 57KHz that is coming up the wires. This is done by adding a switch to interrupt the +9V which is going up to the dome, as this is the line that passes closest to the receiver's input node and thus causes the most trouble. It has to be a switch, because you need that line for generating IR from the beacon in LTTO mode. The cool thing is, though, once this mod is made you have an LTTO that does not have to generate a beacon all the time! You'll want to make sure it is OK with the club/players you normally play with to use such a mod in a game, though... it gives you a distinct advantage.
Anyway, you want to interrupt the heavy red wire going up to the Dome PCB from the Main PCB, and you want to do it as close to the MAIN PCB as possible:
For mine, I just used a two-pin Molex connector and a shorting jumper (used to configure various electronic items like old IDE hard-disk-drives or CD-ROM drives). I would reccomend you find a good slide switch instead, or else use a right-angle connector so you will be less likely to snag the jumper on things while playing:
That's all there is to it!
The Drone I used to test this mod was one of my worst self-hit offenders. Particularly in a certain hallway at work which has dimmable flourescent lighting (which plays hell with the receivers), it would take in excess of 90% self-hits. By replacing the coil as shown, I reduced this to about 10% self-hits, and by then adding the 9V interrupter switch (jumper), it was reduced to 0%. I have not had a single self-hit in all the testing I have done since as long as the 9V line is turned off.
