ALTDuino stands for Altimeter Arduino and is based on the Arduino hardware/software plattform.

I wrote the "ALTDuino Data Analyser" program to setup and optimize the firmware parameters for my ALTDuino altimeter.

The "ALTDuino Unit Interface" is used to setup the ALTDuino and plot the recorded flight to screen. The above example is a simulated flight done by hand motion.

Flight #1

Today was the long awaited first test run of my ALTDuino. It was enclosed in the payload section of my Estes Icarus that I have been flying since 1981. The liftoff weight of the rocket was 75 grams. An Estes B6-4 engine was used for this flight.

My Estes Icarus ready for launch.

The Icarus and it's payload after the flight with the ALTDuino blinking out the recorded altitude (apogee).

The above graph shows the result of the successful logged flight. Apogee occurred at a little over 108 meters while the simulated drogue ejection was triggered at apox. 106 meters.

It's a real nice feeling of accomplishment when viewing the graph after such a successful first test flight of my altimeter.

Flight #2

Today was supposed to be the second test flight.

The rocket pictured before launch. On the left my ALTDuino and on the right an Adrel Altimeter.

Unfortunately the flight started out in a disaster but with an extremely lucky outcome. While the rocket was under full thrust the ejection charge prematurely set off. Due to the high forces the payload contents (ALTDuino and Adrel Altimeter) broke free and were scattered all over the erea! After a thorough search I was very very lucky to find both altimeters in the fields! The nose cone is still missing but I will look for it later.

Update: After work I went back to the field and I'm happy to write that I was able to find the rocket nose cone. Luck was definately on my side.

Flight #3

The next milestone for my ALTDuino was to take place inside a mid powered rocket. With this test I wanted to find out if the measurements at high velocity speeds would be accurately logged.

Louis Schreyer, the maker of one of the best altimeters on the market (Louis' Rocketseiten) was kind enough to take my ALTDuino onboard his Altimax! rocket.
I also included an Adrel altimeter for reference. Louis's rocket had his own Altimax Simply installed. It would take care of recovery duties. My ALTDuino and the Adrel would only be logging the flight.

The "Altimax!" powered by a homemade rocket motor (class H) ready for takeoff.

The flight was almost perfect. Main chute deployment failed due to the parachute having got stuck inside the body tube.

Above is the profil of the flight logged by my ALTDuino.

As you can imagine I was ecstatic after loading the data on to my laptop and seeing the beautiful flight presented on the screen. Everything went perfectly and to add to my delight, my ALTDuino and Louis's Altmax Simply measured the exact same altitude of 361 meters! The Adrel measured 366 meters. I'm a very happy camper to say the least.

Because the high powered flight test was such a success I proceeded in the next step by adding a dual MOSFET device to the ALTDuino. It will take care of apogee and main chute recovery duties.

A dual MOSFET switch plus two 10k smd resisters were soldered onto a small PCB. That intern was placed over the EEPROM chip to make for a compact a size as possible.

The ALTDuino UI now supports velocity data ploted as graph.

Project ALTDuino can now be found under it's own domain - www.ALTDuino.de.

Flight #4

Today another big milestone was successfully completed with the main objective being the test of the MOSFET ejection hardware added to the ALTDuino. Again my old Estes Icarus was used for this important flight. As payload section I used a portion from an Estes Mongoose that housed the ALTDuino (a small prototype electronic bay) and the main parachute. To be on the safe side I decided to use an Estes B6-4 engine with a 4 second delay charge to deploy the first of two 12" parachutes. I did this in case the second parachute set to deploy by the ALTDuino at a preset height of 40 meters would fail.

Liftoff was perfect with the powered flight being straight as an arrow and the rocket only landing several meters from the launch pad. The only problem occurred when the second parachute got tangled at deployment and didn't open. The ALTDuino ejected the main parachute making this test flight a complete success.

Again another beautiful flight profil was captured by the ALTDuino.

Because of todays successful test I felt it was time to protect the ALTDuino with shrink tubing. The finished ALTDuino as pictured above weighs 4.9 grams. The dimensions are 40mm x 18mm x 10mm. The altimeter has leads for 2 pyro charges and 1 lead for connecting to an external mounted LED.

My first piece of hardware is now complete and working. I will now spend many more hours improving and tweaking the firmware.

The final hardware test will consist of using an engine without ejection charge with the ALTDuino taking care of both apogee and main chute deployment.

Flight #5

The big day, the days of all days, the pinnacle of all ALTDuino project tests took place at 06:30 AM this morning. A small field surrounded by woods in the southern part of Germany was the place where I would learn if all the work I put into this project would come to a successful major milestone.
The Estes Mongoose that I had built just the night before stood poised for it's maiden voyage. Onboard was my ALTDuino with a fully charged lipo and configured for drogue and main parachute deployment. Will it work...?

Again I played it safe and decided to stick with a B size engine but this time without an ejection charge as it was not needed. I used an Estes B6-0 and filled the top with epoxy to prevent the hot gases from getting into the main rocket. The payload compartment had an Estes 12" parachute enclosed. The ALTDuino was set to discharge the first ejection at apogee separating the payload bay from the main body section and return under tumble recovery. The second recovery discharge was configured at a trigger height of 40 meters for deployment of the main parachute.

The moment had arrived; Upon ignition everything went into motion and all I could do was watch and hope that every planned sequence would perform as designed.

And that is exactly what happened! After liftoff the Mongoose rose to a height of just under 72 meters (236 feet) with the first deployment charge occuring just after apogee. The rocket then tumbled down until it had reached 40 meters (131 feet) where the second charge occurred deploying the main parachute. Some 8 seconds later the Estes Mongoose with it's valuable payload had safely returned back to earth.

With this flight one of my biggest challenges has come to a very successful end. It was only in February of this year when I started this endeavour having to learn how to program in C+ and understand the hardware, in this case the Arduino platform.

My goal was to finish this project in order to have my very own built and fully operational altimeter for a big event in South Carolina, USA.

So Freedom Launch 2012, here I come... :-)

Flight #6

The purpose of today's flight was to confirm yesterdays successful launch, not that I had a lucky one timer. Additionally I selected a more powerful rocket engine for this launch; A C6-0 made by Weco in Germany was used for this flight.

As with the flight from Friday everything went as it was suppose to. Drogue ejection went off just after apogee and main chute deployment at 40 meters (131 feet). The only unfortunate event was that the parachute got tangled in the shroud lines and never could open. However there was no damage to the rocket or the electronics.

The major test phase of this project complete. Further work will consist of improvements and tweaks.

Flight #7
Flight #8

It looks like I'm on a roll. I haven't flown so many rockets within such a short period of time before. I'm having fun.

Todays goal was to fly another C powered Mongoose and hope that this time the parachute would open up. Well.... it didn't, again. Either it's the cool morning temperature or I need to reevaluate my parachute folding technique. However the ALTDuino worked flawlessly once more.

I decided to launch the Mongoose one more time using a B6-0 so I could make some pictures of the flight. I also made some videos which I will post here at a later date.

It occurred to me having made 2 flights that it would be a nice feature to overlap the graphs in the ALTDuino UI program so they could be compared. This will be my next program update.

Flight #9

As I had 2 flights each of which having problems with the parachute not opening I launched the Mongoose this morning hoping a third try would be the charme. This time I used a different technique to pack the chute.

I also modified apogee detection in the firmware so that the drogue charge event will be more accurate.

The flight went very well. Separation of the rocket at apogee was spot on which indicates the improved modifications to the firmware worked as hoped.

For some reason the achieved altitude was much lower compared to previous flights using the same type engine. This suggests the engine used on this flight was out of spec.
Again the parachute struggled to open up at first but finally did so about 10 meters (32 feet) before touchdown, too low to be noticeable in the graph. I am now convinced this a temperature related issue as it was a chilly 7 celsius (44 fahrenheit) at launch which took place at 6:25 AM.

The ALTDuino UI tool now has a "Compare" function making it possible to display and compare 2 flight profils.

First via the "COMXX" or "Load" button you import the main flight profil. Then the "Compare" button is shown where a second flight profil can be imported into the UI (green graphs).

Flight #10
Flight #11
Flight #12
Flight #13

I had four launches over the weekend. Two on Saturday (flight #10 and #11) and two on Sunday (flight #12 and #13).

In the above graphs you can see one flight with a perfect rocket launch sequence. The first pyro charge went off at apogee and the second pyro charge went off at 40 meters with the parachute deploying bringing the rocket and it's cargo safely back to earth.
The green altitude graph shows what happens when the main parachute opens prematurely. The parachute got pulled out by the nose cone that was too loose whilst the rocket went into tumble recovery.

The weight difference is because the flight on the 19th had a small HD camera on board.

As you may notice in the below picture I was forced to modify the ALTDuino:

I finished the electronic bay for the ALTDuino one day before leaving for the States in preparation of Freedom Launch 2012 in South Carolina, USA.