Nerf Strongarm Mod (laser sight, strobe and torch)

I’d always dreamed of owning a Nerf gun as a child. So when I spotted one on offer at my local supermarket I couldn’t resist. After a few days of gleefully charging around the house with my new strongarm elite I soon wanted more. After looking at some of the mods seen on the internet I decided that I wanted to do something a little different and build a laser target built into the gun’s trigger and add a tactical light to the front.

Strongarm Operational mods

I started with some common strongarm mods: taking out the barrel posts, removing the lock, and filing down the ridges on the side of the slide as it rubs on my palms. I decided against removing the air restrictor after reading in a number of posts that it can adversely affect performance. I also did not do the barrel extension as I saw little point in it. Finally, I got some silicone lubricant and gave all the moving parts a good grease.

In the near future I plan to complete the basic operational mods by installing Orange Mods Unleashed Solid final stage kit

Tactical Light Mod

This was the trickier of the changes. I wanted it to serve 2 functions. The first was to work like a torch, the second was the strobe, like in Kick Ass, to disorientate opponents. My first attempt at this involved encasing the whole contraption in some pipe and bolting it to the underside of the strongarm. In practice, this left the gun poorly balanced and wouldn’t withstand moving the weapon around quickly in a battle. So I built the whole thing into the strongarm.

To switch between the different operating modes I fitted a SPDT switch (on-off-on) near the trigger.

In this position it is easy to turn the light or strobe on and off with the trigger finger without obstructing the trigger. It can also be operated both left and right-handed with ease. The switch’s middle lug connects battery’s positive terminal. Then one lug goes directly to an array of 10 super-bright white LEDs to power them like a torch. The other directs the power to a small 555 timer circuit which then goes to the LED array to create the strobe effect.

The LED array was created using the ends of an old IDE cable. This way the LEDs could be inserted neatly into the holes and all the connections could be hidden away on the underside. Additionally, this made for easier installation on the strongarm as there is not enough room in the front to house it all.

The LED array was then installed using epoxy putty and holes made in the strongarm’s front to allow the wires to pass through.

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Inside the strongarm’s shell is housed two small circuits, the first (closest to the trigger) is the 555 timer circuit and the second is a bank of resistors for the LEDs.

Nerf electronics schematic

Nerf electronics schematic

Since everything was going to be powered by a 9v battery, the 555 timer as a voltage drop of ~2v and the LEDs have a forward voltage 3.1~3.2v the LEDs were wired in pairs and each pair attached to a 470 ohm resistor. R8 is needed to create a similar drop when the LEDs are being fed directly from the battery. This ensures that the LED brightness is consistent in both modes of operation. The diode (D1) this there to prevent current flowing back into the 555 timer when the circuit is operating in torch mode (without it strange flickering occurs).

The battery holder was secured under the gun with superglue and epoxy putty. Attached to this is another end of a IDE cable to act as a patch bay.

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The 2 right-most pairs on the IDE patch bay are wired to the battery’s positive terminal, the 2 left-most pairs are tied to the negative terminal.  This allows cables coming from either half of the shell to be kept separate and easier dismantling and patched together when the gun is assembled. Additionally, I can add other circuits without having to modify the existing circuitry.

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Laser Target

The laser target was designed to be activated when the trigger is lightly squeezed.

A momentary micro-switch was placed under the trigger. As the trigger is pulled the switch lever is pushed down, activating the laser. The markings on the trigger and screw post were used to position the switch so that the laser could be turned on without the strongarm firing. The laser is fitted into the front of the gun and powered off the same 9v battery as the lights.

Completed Strongarm Mod

Completed Strongarm Mod

Conclusions

While shopping for parts for this project my girlfriend kindly pointed out that what I’ve spent on parts I could have gotten a new, bigger, Nerf gun. But it wouldn’t have been as much fun. In hindsight, it would have been easier (and cheaper) to get a bicycle light and attach that to the strongarm (although it might not be possible to get the same strobe rate). I need to improve the accuracy of the strongarm to make the laser target worthwhile. Perhaps the Orange Mod kit and some Stefan’s should do the trick. There’s still some work to be done in tidying up the wires and securing them as reassembling the strongarm is a nightmare. Then I’ve got to finish up the outer shell and respray it.

Adding bits to my strongarm has gotten me wanting to add other battery powered features to the strongarm. If you’ve got any ideas drop it in the comments below.

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~ by Jay on April 20, 2014.

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