Ashrat.net

Action Shot: Nerf Vulcan Video in Action

ashrat — Sun, 04 Dec 2011 03:55:49 +0000

This was setup when my sister and her friend were not at home, so they had a bit of a surprise when they got home.

More videos on www.youtube.com/TheAshrat

Putting Everything Together – Finished

ashrat — Fri, 25 Nov 2011 09:22:55 +0000

The Arduino Uno Board

Connecting various bits and bobs to the Arduino Uno board is the easy bit. I ended up using the prototyping Uno board and jumper wires as permanent connections. It works alright, but probably isn’t a great practice. I decided to trim a few millimeters off the jumper leads so they would fully fit into the jumper pins.

The 9V Cell

Simply connected the positive side to the VIN pin on the Uno board to provide power, and connected the negative side to a GND pin on the Uno board.

The Digital Infrared Motion Sensor

The digital infrared motion sensor came with a header block so it was easy to connect up. I used three jumper wires to connect the motion sensor to the Uno board. The power lead on the motion sensor is red coloured and I connected it that to the 5V pin on the Uno board. It’s voltage rating is 3V-5V. The ground lead on the motion sensor is black coloured. I connected this to a GND pin on the Uno board. The alarm lead is coloured green and I connected this to digital pin number 2 on the Uno board.

The DC Plug

I used this so that I could seperate the motion sensor from the gun at any time. All that was needed was to solder two wires to the inside of the plug. You can untwist the black cover off to see where to solder to. I used a red lead to the center of the plug and a black lead to the outside of the plug. The red lead is connected to digital pin 4 on the Uno board, and the black lead is connected to a GND pin on the Uno board.

The Enclosure

The enclosure is a generic ABS enclosure. The bottom half has 4 screw holes. I cut out a piece of MDF (Medium Density Fiber) board and used the 4 screw holes to hold that in place. On the MDF board, I’ve screwed in the Arduino board, an extra on/off button, and a 9V battery holder. On the front, it was the perfect size to hold the circuit board of the motion sensor in between the top and bottom parts of the enclosure. This si shown below.

PIR Motion Sensor

The Nerf Vulcan Gun

This was a little tricky at times. I had to be careful that I wasn’t going to jam up the firing mechanism and that I could put the bits in place and screw the cover back on when I was finished.

The TIP121 Transistor

This requires some soldering and de-soldering to get connected, but is quite easy to connect. I soldered the collector leg of the TIP121 to the same solder joint where the on/off button is connected to the trigger switch using stranded core wire. I had to remove a small part of the firing mechanism and lift the small circuit board out of its slot with a screwdriver, then de-solder the joint and re-solder with two wires connected. I then done the same with soldering the emitter leg and soldering that to the motor connection where the trigger switch was connected to it. Finally, I soldered the base leg to the DC socket.

This picture below shows the transistor. The coiled up red lead is connected to the on/off switch (Collector leg). The brown lead is connected to the motor with the other red lead in the same direction (Emitter leg). The red lead with the resistor is connected to the DC socket.

The transistor remains inside the handle area in this picture.

TIP121 Transistor

The DC Socket

I soldered the inside of the DC socket the same way as the DC plug on the Uno board. The red wire is soldered to the base leg of the TIP121 transistor. The black wire is soldered to the ground connection of the Nerf Gun battery. This is just next to the Nerf Gun battery holder, not on the motor itself. The DC socket hangs a little on the outside of the gun. I had to cut off some plastic on one of the screw holes to get the wires to fit in when putting everything back together. There is one less screw now, but that’s fine. The hanging DC Socket doesn’t get in the way at all.

DC Socket

The End Result

A gun that my friends and family are now more scared of than before! The only downside is that the firing rate has slowed to down to something like 1 dart per second. I’m not 100% sure why, but I’m not bothered by that at the moment. It works rather well.

Finished Nerf Vulcan with Motion Sensor

The Electronic Circuit

ashrat — Sun, 06 Nov 2011 10:58:31 +0000

The Research

OK, so I got some “Introduction to Electronics” books from Amazon and read some stuff and learnt some theory (Still not great with that). I also studied the basic components from a tutorial I found at www.electronicsteacher.com. It took a while, but it was really worth it and I didn’t need all of the tutorials listed. I found the most important things to learn about were about voltage, current, resistance (Ohm’s Law for reference), LED’s, transistors and soldering.

What I Ended Up With

Having a look around the websites of Electronic Stores like www.altronics.com.au and www.littlebirdelectronics.com, I ended up using the following parts / components.

Arduino Uno (Starter Kit)
Digital Infrared Motion Sensor
TIP121 NPN Transistor
Stranded Core Wire – Red / Black / Orange
Battery Holders / Clips
9V battery
Breadboard
ABS Enclosure
MDF 3mm Wood
Timber Screws – 4G x 12mm
SPST switch
DC Power Line Socket
DC Power Line Plug

I also got hold of the following equipment.

Digital Multimeter
Temperature Controlled 25 Watt Soldering Iron
Solder Wire (Lead free, 0.8mm diameter)
De-Soldering Tool
PCB Holder
Anti Static Mat and Wristband
Wire Strippers
Insulation Tape – Red / Black

The Arduino Uno board also has software to write a program and upload it to the Ardunio board, which I used for this as well.

The Circuit I Put Together

Most of the circuit is actually from the Arduino Uno board, I just had to put together the other components and write a little program. Here is a diagram of what/how I connected the parts to the Ardunio Uno board.

Click Here to download / view the PDF Document of the Nerf Motion Sensor Circuit

The Diagram Explained

Digital Infrared Sensor

This is the component that detects motion by looking at the heat within its view.

PWR – The power supply to the sensor, it can take up to 5V and I am supplying it with 5V from the Arduino Uno board.
GND – The ground for the sensor, connects to a digital ground on the Arduino Uno board.
ALM – This is the alarm pin where some magic happens. When there is no motion, it will output about 4V and when motion is detected it will ‘go low’ to about 0.4V. This is connected to a digital pin on the Arduino Uno, which is setup as an ‘input’ pin so it receives the signal.

Ardunio Uno

There is a lot of pins on the Arduino Uno board, and this diagram only shows the ones I’ve used. This diagram doesn’t show it yet, but it will be powered by a 9V battery connected to a DC Power Socket. I had it powered via USB to my computer during testing.

5V – This is to supply 5V to the digital infrared sensor.
GND – These are used to provide a digital ground for various components.
D2 – A digital pin which is setup as an input pin. The output from the alarm pin on the digital infrared motion sensor will feed voltage into this pin.
D4 – A digital pin which is setup as an output pin. This pin is programmed to produce an output voltage if the voltage on pin D2 ‘goes low’ (When the digital infrared sensor detects motion).
USB – To connect the Arduino Uno to my computer during testing.

(M) – Motor

This represents the motor attached to the Nerf gun.

ON Switch

The main on / off button for the Nerf gun.

BELT Switch

The switch that operates on the belt feed cover.

TRIGGER Switch

The trigger itself.

Transistor

This is just to the left of the motor in the diagram. This will allow current through that part of the circuit if voltage is being received from pin D4. This will turn the motor on to fire the darts.

Battery

This is just to the right of the BELT switch in the picture. This is to provide power to the motor and is the battery included with the Nerf gun.

Nerf Motion Sensor Circuit

The testing I’ve done with this circuit has included a 9V – 12V buzzer in place of the motor. I believe they have the a similar enough power rating for this to work. Being an amateur and still learning, the above circuit took quite a bit of trial and error to get together. The hardest part was choosing the right transistor and knowing how many amps the motor draw. With the help of a multi meter and a blog post on the Internet, I got a good choice.

With the circuit working, I now have to connect it up to the gun, and put it back together.

References

Little Bird Electronics (Online Shop)
Altronics (Electronics Shop)
Teach Me To Make (Blog)
Electronics Teacher (Online Tutorials)
PIR Motion Sensor Tutorial (Online Tutorial)

Disassembling the Nerf Vulcan

ashrat — Fri, 23 Sep 2011 14:06:10 +0000

Screwdriver, Meet Nerf Vulcan

I have disassembled the Nerf Vulcan Gun so I know exactly what I’m dealing with on the inside. This post will take you through how I disassembling the gun, which took a little research and effort to remove some parts of the gun.

Unlike other tutorials, I’ve had the gun for a while with all the bits added and the gun fully built. The other tutorials usually start from a new gun without the top handle or cocking handle attached. This image will show you what we need to remove to get into the guts of the Nerf Vulcan.

Nerf N-Strike Vulcan EBF-25

Tools Needed / Suggested

Philips Screwdriver
Slotted (flat blade) screwdriver
Hammer

Removing Additional Parts

The Battery

There is one screw to remove the battery from the Nerf gun. The battery holder will just slide out once unscrewed.

The Handle

This is the easiest part to remove from the Nerf Vulcan. All you need is a slotted (flat blade) screwdriver or something similar. Just wedge the screw driver between the round orange part and the handle itself, then lever off the orange part. To avoid any damage, I would suggest taking it easy, and slowly work your way around the orange part rather than putting all your effort on a single point. You will need to do this at both sides of the handle.

Removing the Nerf Vulcan Handle

The Belt Feed Cover

This belt feed cover is also easy to remove. You will need a philips screwdriver to unscrew the screws at both ends of the belt feed cover. When you remove the screw, you will also need to remove the round orange part which has the screw in it. I was unable to pull it straight out, so I lifted the screwdrivers up at an angle to pull it out. Unscrew both ends, and your done.

Removing Nerf Vulcan Belt Feed Cover

The Cocking Handle

This is hard to remove, and needs some patience. The best practice is to used the slotted side of the hammer between the gun itself, and the handle. The handle is joined either side by a metal bar, and the goal is to remove one of the orange handles from the metal bar (Thankfully, we only have to do one side!). Keep wedging the hammer in different positions and put some forceful effort into it, just be careful to not try too hard. Once one orange part is removed, you can slide the other side out, with the metal bar removed as well.

Removing Nerf Vulcan Cocking Handle

Unscrewing the Side Panel

Unscrewing took a bit of time. There is at least 20 screws to remove, and it may be best to note down where each one came from. The good news is that you do not have to remove every single screw, just most of them. The picture below shows which ones you need to remove (Don’t worry about the one in the bottom left on the yellow bit). We need to remove all of them from the handle up to the trigger grip.

Removing the Nerf Vulcan Screws

The Inside

To get to the inside, you now need to split the unscrewed half of the gun in half and down the middle. Before you do this, look out for two stickers. There is a battery caution sticker underneath where the battery slides into, and there is one where the belt is fed into the gun. You will need to cut these two stickers in half to make this work. When opening the side, look out for a small orange plastic bit just above the belt feed. It is used for the belt feed cover switch, and will easily fall out. It is best you don’t lose this.

You can see from the picture below where the motor is (The round thing with two wires connected to it), where the belt feed area is which rotates, and the large white plastic part(s) which is the mechanical firing mechanism for the gun.

Inside the Nerf Vulcan

The Electronic Bit

The electronics of the gun are fairly simple. The battery connects directly to the belt feed cover switch, this switch then connects to the main on/off switch just above the trigger, then this switch connects to the trigger switch. The trigger switch completes the circuit and the motor gets going. There is a small circuit attached to the motor, which I am assuming is to protect the motor from a surge in voltage/current. The circuit is finished off by the motor being connected to the negative side of the battery.

References

Tutorial for Disassembling the Nerf Gun

Nerf Sentry Gun – The Beginning

ashrat — Sat, 06 Aug 2011 11:38:06 +0000

Since Christmas 2010, Nerf have got my love quite a bit. They are simply quite fun. My latest Nerf gun is the Nerf N-Strike Vulcan EBF-25, an automatic belt fed gun which can fire 3 darts per second.

I’ve seen some YouTube videos where people have modified it to include a motion sensor and have it fire when someone walks in front of it. I plan to do the same, but keeping it as simple as possible. The videos I have seen are rather complex and way beyond my capabilities.

I figured I need to build a part of an electrical circuit to accomplish this, so I’ve started studying some basic electronics in my own time so I can get a basic understanding of what I need to do. Soon, I shall buy the components needed to make this work.