OldEurope
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Another development from me is my Altimax Altimeter.
A year ago I started working on a new altimeter system, which I finished 6 months ago. The reason for developing an own altimeter was the lack of easy to use altimeters in Germany.
I wanted an easy system which can be used by everyone, also without having a laptop on launch days. The normal altimeters are quite difficult to use, many settings are nice to have, but can lead to failures due to wrong settings.
Also, it should have 2 igniter ports as well as 2 Servo Ports, for those who use mechanical parachute ejection.
So I started from scratch, grounded my first design twice before starting a new attempt. I built a system driven by a ATMega644 with 16 MHz. I has only a barometric sensor on board, but a special digital filter called a Kalman Filter.
It has 2 pyro ports capable of driving 17 A, 2 servo ports with separate power converter, a serial connection as well as an I2C port for the terminal and later developments. A beeper sounds the igniter status, 2 leds show also the status. It runs on 7.4 V Lipo accus as well as 9V blocks, and needs only one power source.
A bootloader allows for easy firmware update from the net.
It calclates the heigt very exactly with the use of the air temperature on the launch site, for this ony can enter the temperature or change it later on to show the height more exact. The accuracy is within 3 meters.
I placed a SubD-15 HD connector to it, so I can switch rockets in a minute, just take out 2 screws, pull the altimeter off and put it in a new rocket.
This turned out to be a very nice feature, which no altimeter in the market has.
Besides this, the best feature is the small LCD terminal I made for it, one can connect it to the altimeter and it lets you change all settings, test the servo outputs, test the igniters and show you the last 6 flights.
It is only 90x70 mm small and replaces the laptop almost completely.
For the computer fans I made a nice software which lets you change settings as well as show you the flight data, besides the barometric data it shows also the filtered data out of the Kalman Filter.
The performance is very nice, it detects Apogee very exact, much better than some available altimeters on the market. The good performance is done by the Kalman filter, which makes apogee detection very exact.
This filter is very effective, it calculates the acceleration and speed out of the barometric pressure. It calculates an allowed error for the pressure, which allows to filter out wrong data. We can even switch off the sensor 2 seconds after launch, and it finds the apogee still quite well, its like magic.
Also with the help of the filter, we look for the point where speed is Zero, that is the point where the right time is for ejecting a parachute. This works much better then the normal way of waiting for rising air pressure.
I built 50 Altimeters so far, and with the help of some club members we did extensive testing, we had over 100 flights until this summer, without a single incident so far. All apogees where detected very nicely, which is also shown in the flight data.
The Altimax (that is the name) is quite large, 80x40 mm, but I have a smaller one (69x23 mm) which fits a 24 mm motor tube and has all features of the big one except the servo ports. The Mini is not ready yet, I have some samples only.
This is how it looks like:
On the left you see the connector. This is the counterpart of the connector which is placed in the rocket and is very robust:
This the LCD terminal, and my Hand ;-)
My PC Software is now completed, but still in German, but that will change soon:
It allows download of the flight data, the altimax is capable of saving data of 6 flights in a fifo manner.
The altimax is not a commercial project, I built it myself and produced a small series for the german rocketeers.
Louis
A year ago I started working on a new altimeter system, which I finished 6 months ago. The reason for developing an own altimeter was the lack of easy to use altimeters in Germany.
I wanted an easy system which can be used by everyone, also without having a laptop on launch days. The normal altimeters are quite difficult to use, many settings are nice to have, but can lead to failures due to wrong settings.
Also, it should have 2 igniter ports as well as 2 Servo Ports, for those who use mechanical parachute ejection.
So I started from scratch, grounded my first design twice before starting a new attempt. I built a system driven by a ATMega644 with 16 MHz. I has only a barometric sensor on board, but a special digital filter called a Kalman Filter.
It has 2 pyro ports capable of driving 17 A, 2 servo ports with separate power converter, a serial connection as well as an I2C port for the terminal and later developments. A beeper sounds the igniter status, 2 leds show also the status. It runs on 7.4 V Lipo accus as well as 9V blocks, and needs only one power source.
A bootloader allows for easy firmware update from the net.
It calclates the heigt very exactly with the use of the air temperature on the launch site, for this ony can enter the temperature or change it later on to show the height more exact. The accuracy is within 3 meters.
I placed a SubD-15 HD connector to it, so I can switch rockets in a minute, just take out 2 screws, pull the altimeter off and put it in a new rocket.
This turned out to be a very nice feature, which no altimeter in the market has.
Besides this, the best feature is the small LCD terminal I made for it, one can connect it to the altimeter and it lets you change all settings, test the servo outputs, test the igniters and show you the last 6 flights.
It is only 90x70 mm small and replaces the laptop almost completely.
For the computer fans I made a nice software which lets you change settings as well as show you the flight data, besides the barometric data it shows also the filtered data out of the Kalman Filter.
The performance is very nice, it detects Apogee very exact, much better than some available altimeters on the market. The good performance is done by the Kalman filter, which makes apogee detection very exact.
This filter is very effective, it calculates the acceleration and speed out of the barometric pressure. It calculates an allowed error for the pressure, which allows to filter out wrong data. We can even switch off the sensor 2 seconds after launch, and it finds the apogee still quite well, its like magic.
Also with the help of the filter, we look for the point where speed is Zero, that is the point where the right time is for ejecting a parachute. This works much better then the normal way of waiting for rising air pressure.
I built 50 Altimeters so far, and with the help of some club members we did extensive testing, we had over 100 flights until this summer, without a single incident so far. All apogees where detected very nicely, which is also shown in the flight data.
The Altimax (that is the name) is quite large, 80x40 mm, but I have a smaller one (69x23 mm) which fits a 24 mm motor tube and has all features of the big one except the servo ports. The Mini is not ready yet, I have some samples only.
This is how it looks like:
On the left you see the connector. This is the counterpart of the connector which is placed in the rocket and is very robust:
This the LCD terminal, and my Hand ;-)
My PC Software is now completed, but still in German, but that will change soon:
It allows download of the flight data, the altimax is capable of saving data of 6 flights in a fifo manner.
The altimax is not a commercial project, I built it myself and produced a small series for the german rocketeers.
Louis
U$D?
