2

4.8 V and 6 V. Ideally the gun needs 6 V but it runs just
as well with 4.8 V rechargeable batteries. At 6 V, the
unit will use approximately 14 W of power to fire the
darts, that’s 2.33 A for the two motors.

MOTORS
In the forward third of the gun there are two opposing
DC motors that use polyester/ hard plastic wheels to
squeeze the darts through the barrel and generate the
speed necessary for them to fire. These motors each
use around 1.16 A of current at ~6 V. The balance of the
gun is forward-heavy, so when looking to mount the
gun to a rail or a servo/stepper, be mindful of where
the weight is and balance accordingly.

SAFETY SWITCHES
While Nerf darts are relatively safe, it is great to see
that there are two safety switches that prevent the
gun from firing. First of all, the magazine containing
the darts must be inserted in order for the motor
to spin. The magazine pushes a normally closed
switch, enabling the motor to be triggered using the
‘accelerator’ button; without the magazine the switch
is open. The second safety is located in a hatch at
the very top of the gun. This hatch is used to clear
any jams that may occur when the darts are pushed
through a soft plastic aperture. The hatch forms
a normally closed switch by pushing upon a black
plastic switch. These switches can be bypassed,
as electronically they are just momentary switches/
microswitches that can be soldered into an always-
closed circuit. Obviously this is done at your own risk,
so don’t look down the barrel when operating the gun!

ELECTRONICS
The electronics for the gun are remarkably simple:
we see a capacitor connecting the batteries to the

main circuit. The capacitor is used to stop a rush of

current being pulled by the motors. As long as the

safety switches are closed (magazine loaded and the

hatch closed), then the user can fire the weapon. The

motor noise could prove to be a handy by-product

for cosplayers, as it is close to the chainsaw bayonet

found in the Gears of War series. Internally there is

space to install small microcontrollers (Arduino Mini/

Micro, Teensy, micro:bit etc), or even a Pi Zero W.

Obviously this would require a better power solution

than AA batteries, but the battery holder could be

easily modified using a rotary tool to accommodate a

USB LiPo battery back.

COSPLAY

This is a fantastic gun for cosplay use, and it bears a

resemblance to the Lawgiver weapon used in the 2012

Dredd movie. The plastic is hard-wearing, and it can

be easily modified and drilled into, so adding a laser

sight and other ‘greebles’ (fine detail added to a prop to

make it look more complex), is extremely easy to do.

To fully customise the gun, of course, it needs a

paint job! A light sanding to roughen the surface will

also enable smooth spray-painting, to a colour of your

choosing. Careful – this will depend upon local laws

regarding replica firearms and, for cosplay use, it will

need to be vetted by event staff.

CONCLUSION

This is a fantastically cheap and robust base for many

projects. The user-accessible chassis is easy to modify,

the electronics are simple and easy to incorporate into

a microcontroller/computer project, so seven-segment

LED panels, OLEDs and audio playback can bring this

gun to life – just remember to improve the power. The

plastic used for the gun can also be primed for painting

and used in many cosplay scenarios. All of this can be

yours for less than £20, a bargain for those taking their

first steps in modifying toys and cosplay.

EXTRA

STYLE

Adding custom

features to the

Nerf gun is easy,

the plastic is

easy to work

with and can

be shaped and

drilled into with

a rotary tool

or basic hand

tools. Adding

LEDs and sound

effects, using

audio boards, is

possible thanks

to the large

internal space

available; all you

need to do is add

a better power

supply. If you

have never done

anything like that,

then now is the

time to learn new

skills from those

who have.

Left

The magazine locks

directly inline with an

aperture that covers

the opposing motors

that fire the darts.

The spring-powered

trigger pushes the

dart into the aperture

as part of the

firing process

Above

The internal structure merges simple mechanical steps, such

as a spring-powered trigger, with electronic safeties to prevent

fingers being trapped when the motor starts

FIELD TEST