Introduction: Conversion of Cheap Airsoft P90 to Miles Laser Tag.

About: Artist/Engineer of my own company , only been doing the art side of my work for 3 years now
This is the Instructable on converting a inexpensive airsoft weapon into a MILESTAG  laser tagger. For those unfamiliar with Miles tag laser tag. it is a system that takes the game of Laser tag and turns it into an adult Military sim experience. individual parts for building your own can be found here, In this case we are building a tagger using the Ls20/20 laser module from LaserSoft  . this will allow us to build our tagger wihtout needing the large tube and lens assembly and we can build a much more "real" looking Tagger for our Military Sim or "milsim" for short

Ranges for Milestag systems start at 150 yards (minimum for a rifle) and can reach out as far as 300 yards . The system allows for variable damage, Ammo count (rds per magazines  X number of Magazines ) rate of fire, how much damage you can take. 4 teams red, blue, yellow,green, and how much damage you can take before you are dead or respawn. Sound effects can be changed as well so a p90 sounds like a p90 , M4 a m4 , a saw .. ect

Step 1: Starting the Teardown

This is your basic electric P90 airsoft  tagger from Airsplat . generally will will run you between $25-$30.00. and come with battery , charger and a bunch of add on parts.

Step 2: Before You Remove the Screws

First thing you are going to want to do is remove the magazine , Open the back door and take out the battery , unclipping it from the molex connector. You will be using the battery for the Milestag brain. it is perfect at 7.2v to drive the electronics.

Step 3: Parts Removal Before Screws

Before you do anything else , very carefully pry up on each side of the rmagazine retainer assembly to slide it free. be careful as it is spring loaded and will want to launch itelf across the table. Then remove the front weaver rail mounts and the strap retainer.

Step 4: Removing the Screws

All of the screws are easy to find, nothing hidden. just there are quite a few of them. Remove them one at a time then caarefully split the case with a flat head screwdriver. if the case does not come apart easily then you my have missed a screw.  the gearbos an d barrel will fall right out of the gun.

Step 5: Cutting the Motor Out

You will now cut the wiring from the motor . you will be keeping the molex connector and wire for wiring to the Milestag board .

Step 6: Trigger Assembly Removal

You will now remove the trigger assembly , safety, and spring loaded safety retainer
then remove the muzzle cap, it may be glued into place so take your time to work it free

Step 7:

Note, the trigger switch will be reused in this build (just below my thumb) remove it and Desolder the wires from it. this will free the
positive lead that will be connected to the key switch . Next you will need to take measurements of the display. In this case we are using a display from Sparkfun simple locking calipers allow us to make sure our size and location is correct. 

As you can see I used a feature on the tagger as an alignment point to mark out out holes

Step 8:

As you can see we cut out the hole using a dremel and a flat hand file. we then located a spot for our 2 inch speaker. We then drilled  5  1/4 inch holes . the speaker we are using here is surplus stock previously used in a old laptop . I highly recommend using a mylar/plastic cone speaker .

Step 9:

Next thing we do is get our holes cut for the reload switch and key switch. Now you don't need to use a Key switch but most of the Milsim groups like it if you install one. It prevents anyone from "accidentally" turning off their gun during combat. , Generally thin this case we decided to mount the key so it will be under the magazine. We cut out half the hole for it and put both halves back together to make the full hole for the switch.

Then we drill out a hole for our reload push button. So far everyone agrees that this is the best place for the reload.
the pushbutton is from Radio shack.

Step 10:

As you can see here is our key switch and how it will look once we put both halves together. At the same time we dremel two hole in the front of the tagger, One will hold a high brightness red LED for the muzzle flash, the lower one will be a hit sensor  for the front of the gun.

Step 11:

Next we wire our power up. The original molex connector ground is soldered directly to the micro board then a lead to the key switch and the V+ from the molex to the key switch . now I usually hook up the speaker as one of the first things since it allows me to test the Milestag board as I assemble it. Shot /reload and hit sounds allow me to test each stage of the build.

Step 12:

Next we wire the micro board. In this case you have the sensor wires , Laser power/muzzle flash wires and the trigger reload wires. I highly recommend that you use hot glue to strain relief and immobilize the wires If you are using molex connected type. a dab of hot glue to keep it in place is recommended as well. Again as you hook up each item. test to make sure it actually works before mounting the board permanently.

Step 13:

Next you will need to mount your LS20/20 IR laser module into the barrel housing end. In this case since the size was different we needed to use a nylon spacer. A little super glue and we had it all set .

Step 14:

Next we take out muzzle flash LED and install a 100 ohm resistor to it. then wire it parallel to the laser module. 

Step 15:

At this point we wire up a single TSOP sensor and hotglue it into place in line with the lower hole. The muzzle flash LED is mounted just above it , we then wire the reload switch and the trigger switch and replace the switch into its original place. Power switch is mounted with a little superglue. Hot glue spots holds the wiring into place.

Step 16: Mounting the Display

Okay so next we mount the display. Now instead of using the ribbon cable for an interconnect for the board  that is recommended by MILES , we are going to use a connector previously used as a motherboard connector for USB. Color coded and allot easier to work with and push onto the board this is a better solution than a ribbon cable.

Now we power it up , ensure the orientation into the body of the gun and then flush mount the display. the board will sit about 1/4 an inch from the case.  I then fill that spot with hot glue to hold it into place.

As you can see we added foam to the back of the speaker

Step 17:

Next we flat mount the main board  with hot glue and epoxy /and coil up the remaining wire. this should be followed by covering the whole setup with some form of plastic  in this case some antistatic foam wrap.

Now we have 4 wires for the cat 5 connector that will support the external sensors for the head/chest

Step 18: Sensor Connector

Now  we decided a long time ago that the simple phone jack was not strong enough for the rough and tumble of Milsim combat
I highly reccomend that cat 5 adapter is allot stronger solution for your external sensor set. Just like the Key switch we half and half mount the connector. 

Step 19: All Wired Up and Ready to Reassemble

All finished up we check all functions of the tagger, and make sure clearances are good for reassembly 

Step 20: FInshed and Reassembled

We cut a hole in the bottom of the magazine to allow us to turn the key via opening the loading door

Now we just reverse the first 4 steps to re assemble the weapon and test it. and there you go!.

I hope You have enjoyed the break down and rebuild conversion to Miles Tag laser tag weapon.
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