So on a slight upgrade from my last launcher I made a new model rocket/Fireworks launcher using an Arduino microcontroller . This project was inspired by this wireless fireworks controller and this microcontroller rocket launcher . I really did not want to dedicate my launch device to any one specific role since celebrations are far apart and model rockets are somewhere near the middle of my list of hobbies.  By combining the two different devices together I was able to achieve what I wanted.  Most of my original drawings are found here…

I was going to use the ATmega32 microcontroller because of its quantity of digital I/O lines but settled on using an Arduino Diecimila for prototyping and RBBB for implementation. Keeping things simplistic but still allowing a workable user interface I decided on only using 4 buttons and 2 switches.

• Power Switch:
• Turning the device on and off.
• Key Switch: Activating the launch screen and final authentication method before launch.
• Left/Right Launch Buttons: Menu Navigation, login acceptance and launch.
• Up/Down buttons: More menu navigation.

The ATmega168 only has 14 digital I/O lines and I will be requiring at least 1 for each switch and launch terminal.  Two 8-bit shift registers give me 16 terminals and are super nice because in order to operate both you only have to sacrifice Three pins. Here are some things I wanted to include

• Startup melody
• Password authentication
• Key Switch
• Ability to change launch configuration such as delay and patterns.
• Screen for pattern selection and other settings.

Here is the finished prototype. Basically this is just a proof of concept and also it allowed me to finish the software prior to installation. You can see the black 16pin shift registers each broken out to LED segments. The yellow chips are 330 ohm resistors.

I finished the transistor board after lots of soldering. Each output from the shift registers are connected to the Base of the Transistor through a 1k resistor and each pin has a pull-down resistor as well. Instead of using one power source, the terminals will be broken up into four power sources. Two 9 volt batteries in series will feed each section of 4 terminals. Eight batteries for the launch system and two more for powering the microcontroller, LCD screen, LED’s and etc. To help take the initial shock current off of the 9v batteries each of the four sections has a 4700uf cap. The smaller cap is part of the 5v regulator system for all the controls.

Using an old floppy cable I connected the transistor board to the Arduino RBBB. And then some more for connecting up the switches, buzzer, led’s and LCD screen. All that is next is to wire up the terminals to the transistor board and then mount it all in its case.

Well wire that up and get some more batteries :)

After acquiring the batteries and finishing up the wiring I started looking for a case. I knew that I wanted something pelican-esk. I found this Plano waterproof case at Academy Sports an everything fits inside perfectly. The next problem was what to use for the lid to mount the switches to. Three walks around my house landed me with some plywood, Plexiglas and a clipboard. The clipboard almost fit to begin with so I chose to use it. After some hot glue here is the result.

I had to recess the top piece down some for the red arming switch to clear the case lid. I really like the looks of how this turned out.

The launcher booted up and armed, ready for launch. I should probably mention the two momentary push button switches to the right of the LCD screen. I used some felt with sticky on the back to cover them up and still show their location. I would probably use larger push buttons that were mountable if I had to do this over again.  Also each launch button  (bottom left and right) have built in blue LED’s which didn’t show up in this picture.

Steps to get to the launch screen include:

• Turning the power on
• Entering in launch code.
  • Press and holding both launch buttons to verify code
  • If code is wrong it notifies the user and reboots
• Selecting the launch array which include
  • Every terminal
  • Every odd terminal
  • Every even terminal
  • Terminal #1 only
  • Every terminal with a 1sec delay between
• Then inserting the key and turning it to the on position.
  • This arms the system and turns on a relay which connects the battery packs to the transistor board.
  • Also when armed the launch buttons light up bright blue.
• Pressing both launch buttons simultaneously.

Inside the case the first thing to notice is the battery array. Two for each terminal and two for the launch system. Hot glue was mainly used to hold things together but some other reinforcement will be added before this sees field use.  A short test of each terminal and all buttons and this is ready to see its first rocket or firework.

Coming this New Years will be another video of it in action but here is a short demonstration video.

Microcontroller Rocket/Firework Launcher from Adam on Vimeo.

Things to Consider
If I were going to do this again I would probably try to use a different power source. I think a rechargeable alarm battery would be easy to integrate and also would allow recharging. As I said before I would also use different up down buttons next to the lcd and try to trim the edges of the lcd with something more professional looking.

I have some Ideas of things I will add or change such as more launch arrays and a login password that is changeable via the device and not software set. Adding a security measure of having to press the launch buttons within a certain amount of each other would be doable and make accidental launch less likely.

One thing that I am planning on adding for sure is some type of remote, probably wired, to set off the rocket or fireworks from an even further distance. I’m thinking of using a project box and telephone cord for this but if you can think of something better let me know!

If you would like the code or schematics email me and I will send them to you. Thanks

• Flight Computer x2
• Cutdown Mechanism x2
• Aileron Servos x2
• Temperature Sensors x3
• Altimeter
• Compass
• GPS
• Packet Modem x2
• Digital Camera
• Accelerometer
• Battery
• FM Beeping Tracker

These are the systems that will control the glider as of now. The list shouldn’t change unless I come up with a better idea later on into the build. The current components that I already have are:

• Prototype Flight Computer
• Camera
• GPS
• Both Aileron Servos
• All Temperature Sensors.

I am using Arduino micro controllers to basically run the glider. Since there are so many components and calculations that have to occur in real time, I plan on having two for redundancy and processing power. To prototype I am using the Arduino Diecimila because of its easy usb interface. For actual glider use, two Arduino Nano’s will be used because of their tiny footprint and weight. The I/O pins are the same between the Diecimila and the Nano which will make the swap over very easy. Cost (Diecimila) $35.00

Arduino Nano

The camera was purchased off of Ebay with a broken LCD screen… I am stripping all of the cover and excess weight off of the components anyway so this makes no difference. The less the glider weighs the better. Cost $20.00 Not any ordinary GPS unit can be used for these high altitude trips. Laws are in place that restrict gps manufacturers from making units that will work over 60,000ft or 1,000mph. I was however able to find the Garmin 35 Series, that were made before the laws became active. It uses a serial connection to talk with the Arduino. Cost $25.00

I actually had a friend that I traded some component for two super sub-micro 6g servo motors. Cost $0.00

The temperature sensors I decided to use are the 1 wire type and are free samples from Maxim-ic. Cost $0.00

Glider Types:
One of the things that took the longest for me to decide was what type/style glider do I want to make? Having no prior aeronautics or RC Glider/Plane experience, I looked at all possibilities. Looking through articles and talking to people on forums is where I gained most my knowledge. I had to figure out if I wanted a glider that A: Stays in the air the longest. or B: Glides the furthest. I decided to go with B since I may eventually have the glider land at a far away location. It would be very interesting to have it fly X number of miles and to take pictures of its journey. The biggest issues that I have to think about when deciding which glider type to use are weight and strength. I need to make this entire project as light as possible as to meet FAA regulations for amateur ballooning. Looking at the results from Mark I, I found that great speeds and G forces will occur during initial cut down and pullout. Here are the designs I have been considering and why I am considering them.

Glider Types Part II:
(These images were taken from Google and I am in no way affiliated with them or their takers)

I found this military glider and really liked the wing design. It looks very stable and likely to give a very good glide ratio. Although that was before I knew what happens when you take a glider over its maximum speed.

That video is even more appropriate for this design. I found this one before I saw that video also. The things I liked about this design is that it has room upfront for the electronic components and could be controlled by 1 vertical servo and 2 horizontal aileron servos. Which is better for redundancy.

I found this RC Glider and at first didn’t like the V tail. However, by using the V tail I can eliminate an entire servo and only use 2 for controlling the glider, this is still redundant if one decides to fail. The streamlined fuselage would have less wind resistance and the large wingspan would offer a better glide slope. The only downside is that I don’t think there is enough room for some of my larger components.

I must have spent at least an hour looking this single photo over. It is a great collection of RC Gliders and looks tremendously fun. I never expected to find them as large as shown here. I would love to build one as large as the tallest ones you see but don’t know if I can keep the weight down and strength up.

Finally I found the one I am gong to use. It can be made strong enough, light enough, and still have room for all components. Unless some other better design pops out of the wood work, this is the one. I doubt that any glider kit out there is strong enough for my needs so it is inevitable that I will have to make it from scratch. Which suits me just fine!

So now onto the components to go into the glider. Here is a small list of the main ones.

• Microcontrollers
• Camera
• Redundant Cutdown Controllers
• Temperature Gauges
• GPS
• Communications
• Glider Controls

One of the main things I want to get back from this project is high resolution pictures of the earth from extreme heights. I was planning on using an old 4mp digital camera to do this but an ebay search and 25 dollars later I landed myself a nice Cannon 8mp digital camera complete with broken lcd.

Most gps manufactures have restrictions that are in place to keep people from using the receivers for guided missiles and such. They fail to work above 60,000 ft or over 1,000 mph. Now some manufactures take this request as an OR statement. Either shutoff above 60,000ft OR over 1,000mph not both. I was able to find one that was made before these regulations took effect. It is widely used by amateur balloonist. The Garmin 35 series.

So after a quick ebay search I found one for 20 bucks.. sweet. After stripping off the weatherproof outer shell here is what you’ve got.

The gps ended up having rs232 outputs and the Arduino accepts TTL level serial.. So a max232 circuit later and we are all set. The camera is extremely light after removing the cover and batteries and there was also quite a bit of change on the gps once its protective shell was gone.

So now there is only one main component left to find. Communications

Now the glider link above used a packet modem and the Payload link above used HAM radio.. Since I don’t have any ham radio equipment let alone a license, I think I’ll stick with a packet modem.

Oh yeah. Almost forgot that I am broke and in college (typical). Off to find a cheap way out. Wala, Meet the Motorola C168i. This 9 dollar phone with 25 dollar airtime will give me 3 months or ~150 text/SMS messages of use. Also it can be refilled whenever I decide to launch again. One downside, GSM cell coverage typically cuts out ~10,000 ft. but then again it is going to have to come down eventually.. It absolutely amazed me how easy it was to interface. The headphone jack is also a TTL serial port.

And next to the other components with a 3″ cardboard tube in the background (probably going to be the (mold for the) fuselage.

Ok so now the GPS is ready to integrate and so is the Cell phone. I put off working on the camera any more because I didn’t know what all I wanted it to do. I finally came up with it taking pictures every ~20 seconds and videos at various moments (launch, cutaway, landing). I used some bent wire to make sure I had the correct traces located and proceeded to remove the plastic cover and dome switches.

Next I securely attached and soldered the wires to the camera.

Here is a picture of the really bare bones board (RBBB) Arduino Kit from Modern Device. They are so much smaller than the Diecimila.

I used female headers on top instead of male headers on bottom. this will allow me to directly connect them into a breakout board im making from scratch.

Three of these will be in the glider and here are their individual functions.

Flight MC1:

• GPS data
• Temperature sensors
• Pitot/Static Tube

Flight MC2:

• Camera Timer
• Camera Servo controls
• Swap camera between video and picture modes
• Reset A1 or A3 if they fail to check in within a specified time

Flight MC3:

• Servo Controls (for glider)
• Flight Calculations.
• Cutdown Controls 1 and 2
• Ground Communications
• Chute Release

And here is the flight computer and other major components awaiting code testing. I just need to finish wiring it up and am still waiting for the third flight computer (freeduino). Once that has arrived I’ll start testing some code out to make sure that I can get every system working individually before I put it all together.

Project Still Underway! (Stay Posted)
- Due to insufficient funds this project is being put on hiatus until I am able to pick it back up again.