Introduction: RoboCop Gun
This is Part One for my New Robocop Instructable for my Son. This is how the Gun was made . It works by pushing a micro switch on the gun handle which lights up two bar graphs until fully lit. At the moment Im having trouble embedding my video so Ill post the links to you tube here .
Materials Needed :
Toy Plastic Gun
Wood or cardboard
Ardunio Uno Board
male to male breadboard connections
ATMega328pu microcontroller (with Arduino bootloader pre-installed)
2x10µF ceramic capacitors
16 MHz crystal
circuit board making Kit ( Wires , copper board , print paper , Permanent Marker , Copper etching solution)
Piece of copper strip board
1 x micro switch
1 x on/off toggle switch
2 x Bar Graph LEDs
4 AAA battery comparment with pp3 Battery connector
Drill with small 1mm drill bit
Soldering Iron and Solder
Black Spray Paint
Step 1: Creating the Gun Shape - Part 1
I tried to take as much as I could from the parts of the official Robocop Gun shown in the images. I recreated it using Photoshop breaking it down into the different parts needed to make it look similar. ( Photoshop Image currently not available I will add this to photos later on )
Then I bought a normal store toy gun for kids and used these dimensions to determine the size needed for my extra parts which will be added to it later on. I altered the dimensions on my Photoshop Image until they where correct ( I also had to sacrifice the length of the gun barrel compared to the original Robocop gun as this has to fit inside a compartment strapped to my sons leg). I then printed the parts out on normal paper.
These where then cut out and glued onto a thin wood ( I used the wood bottom of a set of drawers ) and the shapes cut out . I made 2 x sets as there are two sides to the Gun.
Next I had to work out where my bar graphs would be situated so i positioned them and traced around the shape using a permanent Marker. I then cut out the shape using a drill and a small hacksaw.
I also Removed the plastic top of the barrel on the gun to be reattached later on.
Step 2: Creating the Gun Shape - Part 2
With The Gun now split in half it was ready to attach my wooden parts. They where hot glued onto the gun as per my Photoshop template.
At this point I went a bit " lets see what we can attach " crazy and found what I think was some sort of mac donalds connection toy and started glueing these parts onto the gun to make it more space age looking. Wasn't needed and was maybe moving away from the original design but I thought it would look well when finished.
With the parts glued in place , I covered the wood in a metallic finish Duct Tape . This was mainly to hide the wood grain before spraying.
I also noticed that with the attachments added the top of the gun had a large empty space something that the Photoshop image didn't show me . To fix this issue I cut out a piece of polystyrene foam to fit the gap and covered that in the metallic duct tape .
The final Part was to reattach the end of the barrel also assisted by another small piece of polystyrene.
The parts when then sprayed a Matt black, left to dry and repeated again.
Step 3: Setting Up the Bar Graph
This was the tricky part .
Firstly I purchased an Arduino Uno board and downloaded the relevant software. I spent a few hours learning the tutorials which there are plenty of .
Links are here :
Ardunio Software : http://arduino.cc/en/main/software
Arduino Tutorials: http://arduino.cc/en/Tutorial/HomePage
With this basic knowledge and with the help of google I finally got my bar graph lighting up in sequence when a micro switch was pushed and to turn off when it was pushed again.
I have no idea yet how to attach my Arduino code onto this but I can send it if anyone does want it.
When doing this the switch needs to go through a 10k resistor then ground to ensure that the switch works 100% of the time.
Step 4: Moving on to the Breadboard Arduino and the Second Bar Graph.
So as I eventually want to move this to a custom micro Arduino board to fit inside my gun . So I had to make myself an arduino board first using a breadboard.
Now I could go into the ins and outs of how this is done but there are already a lot of examples on here to do this which is where I first found out to do it .
Here is a link to the instructable I used to do this : https://www.instructables.com/id/Standalone-Arduino...
The parts needed are very cheap and easily found on Ebay.
Basically I programmed the ATMega328pu chip on the Arduino first then added it to the Breadboard.
So now I have one working I want to test and see if I can get two working the same at the same time. The simplest solution is often the best right ? Actually yes in this instance it was. Basically I connected the second Bar Graph into the same outputs on the Ardunio board so they are effectively in series.
Step 5: Creating the Custom Micro Board
Again this was a first for me but wasnt too bad once I got going.
First of all I had to design my board. Based on the Breadboard example I knew which connections i needed from the chip and which I didnt. I also measured the inside compartment of my gun and cut a copper plate to the exact size. Now I knew what area I had to work with.
Because of the connections from the Arduino Chip I knew this had to be in the middle.
I found a useful free schematic software called EXpress PCB
Using this software I was able to minimise my PCB to fit within the required area. ( I have attached my PCB Board file , there are two in one : one is the robocop gun controller and the other is a general Arduino replacement board )
Step 6: Micro Board Printing and Transfering
Once I have the PCB the way I want it . I know print out onto A6 Photo Card. ( I learned that photo card or paper was best for transferring the pattern onto the copper Board)
I printed out 6 per card so I had extras if anything went wrong and cut out one of them after printing for use.
I placed the printed PCB Ink side down on top of the copper board.
Secured it with Masking Tape
Using a Hot Iron I basically ironed the pattern onto the copper board.
This took me somewhere between 10 - 15 mins in total. ( I did read that it should only take 5 mins so maybe I was missing something but it took longer for me )
Step 7: Micro Board Etching
With my pattern now imprinted onto my copper board I notice some gaps which didnt transfer. Using a Ruler and a permanent Marker I fill in the areas missed .
I prepare my etch solution. I used a copper etch kit I got from maplin . The instructions will differ depending on which kit you are using so read instructions on whatever kit you have.
Next I submerged my board in the acid solution , within a few hours the copper which has not been marked has been etched away leaving me my connections.
I wash off any remaining paper using soap and water and remove any black ink using nail polish remover.
Lastly I drill my holes for each of the pads using my 1mm Drill bit.
My Board is ready
Step 8: Testing the New Mico Board With the Two Bar Graphs
I now have my board and continue by soldering the ATMega328 chip , 2 x 22 pF ceramic capacitors and 1 x 16MHz Crystal to it and I have soldered all 11 wires ( 10 Inputs , 1 outputs ) onto each of the bargraphs. ( I soldered the negative points of the bar graphs to each other and had one lead coming out to ground) and then to each of the correct points on the board.
I connect my power supply ( 4 AAA Batteries providing 6volts DC ) and my micro switch .
Step 9: Fitting Everything Together .
Now Ive got everything working its time to squeeze inside the gun and believe me that is the correct term.
I have to cut off inside sections , screw points etc to get this to fit . The image shows one half the other half of the gun looked the same .
Once I got everything and drilled my hole for the micro switch on the gun butt .... It should be visible in the images above the logo. I hot glued the gun together.
I kept the bottom open so I could insert new batteries into it just before Halloween and added an on / off rocker switch to the bottom of the butt.
These where then all glued into place and Finished - (Childs Robocop Suit to Follow)