Altimeters and accessories – Altimax stands for safe function

With the Altimax series I offer a range of altimeters for model and high-power rockets. Through years of further development, I can supply very reliable components which, thanks to their robustness, greatly increase safety when recovering rockets. They can already be used in small models, but even very large rockets can be safely salvaged with them. In addition to hobby model rocket pilots, my customers include national and international universities, other research institutes, schools and the Bundeswehr.

What do you need an altimeter for?

Altimeters are mainly used to recover rockets safely, they ensure that parachutes are ejected at certain points to allow the rocket to land safely. A further field of application is air launches or multi-stage flights, in which additional rocket engines are ignited in the air. And of course the data logging, the recording of flight data such as altitude, speed, etc.


The Altimax altimeters are installed in the rocket and measure the position of the rocket with the help of pressure acceleration. In addition to the altitude, the velocity is also calculated, 200x per second. This data is fed into a Kalman filter, which uses all the values together to calculate the position of the rocket. The controller of the Altimax constantly evaluates this attitude and reacts to changes. Since the Kalman filter calculates the position based on the last data, it can react very precisely to changes, e.g. the peak of the rocket is hit very accurately.

Depending on the state and setting, the altimeter can then activate existing outputs, e.g. ignite a fuze at the apogee, which in turn ignites the ejection charge for a parachute. Servos can also be activated. It is also possible, for example, to ignite a second stage after a main motor has burned out. In total, 15 events can be connected to 11 actions on the Altimax G4. Thus, almost everything is possible that can be imagined with an altimeter. Timers can be started, outputs can be activated or servos can be moved.

All functions are adjustable by PC, with our free Windows software, or also by LCD terminal, the terminal is a small device that is simply plugged in and allows all settings without PC. It can also display altitudes.

2-stage recoveries are very easy to realize, a small parachute is ejected at the apogee, then after descending to a certain altitude the actual main parachute is ejected, thus the rocket drifts much less.

The software in the altimeter also monitors the flight attitude and ignites the parachutes if a crash is imminent, so horizontal flights, for example, are stopped reliably and quickly. The larger models also record the measured values, the data can then be read out and evaluated on the PC. In addition to the sensor data, all voltages of the battery and at the igniters are also recorded.

Comparison of the currently offered altimeters

  AltiMAX G4 Altimax Simply 2018
Dimensions 68×26 mm 35×21 mm
Weight 13 g 4,6 g
Input voltage: 7,2 – 12 V 3,3-12 V
Power consumption* (without servos and terminal) Ca. 23 mA ca. 5 mA
Pressure range 10 – 1200 hpa 0 – 1200 hpa
Height range -170 – 31000 m   ü.N.N -170 – 31000 m   ü.N.N
Memory 4 Mbyte
Number of ignition channels 3 2
Number of servo channels 2
Number of additional I/Os 3  
Ignition duration 3 Sec 1 Sec
Ignition voltage =Battery voltage =Battery voltage
Max. Ignition current 15A  9A
Accelerometer Yes +-120G Nein
Servo supply 5V, max 1 A
Resolution height ca. +- 0,15 m ca. +- 0,15 m (1m Ausgabe)
Resolution acceleration +- 0,04G
Sampling rate pressure 204.800 sps 204.800 sps
Sampling rate acceleration 200 sps
Storage rate** 200 sps / 40 sps
Storage duration approx. 5 Flights a 10 min.