We present each of the citizen science experiments that will be taken to the stratosphere in the #SERVETVII launches, in autumn 2022. 4CHAB is a project by Oscar Loras.
The OBC (On Board Computer) of this probe is a Raspberry Pi Zero. The plan is to carry two LoRa devices, either two Ebyte or one Ebyte and one Ra-02. The idea is to use both on slightly separated centre frequencies (we can move by configuration between 410 MHz and 440 MHz if necessary) to implement full-duplex communication with the probe.
The main experiment consists of sending commands to the probe and having it echo them back, to check the feasibility of sending control commands from the ground.
The secondary experiment consists of an experimental rope-cutting device. In the experiment we will not cut the rope joining the probe to the launch train; instead we carry a small rope attached at both ends to our probe. The design of the device will make the rope run through its interior and stay in permanent contact with a resistor made of nichrome wire which, through a transistor controlled by a GPIO of the Pi, would control the moment of the cut.
The system itself will be powered by an auxiliary battery inside the Pi, and the electrical system would carry a physical safety mechanism (the arming of the circuit) that would be removed only before the flight.
In essence, we want to see whether we can order the rope to be cut at the moment we choose (manually or programmatically).
Finally, if time allows, we would carry out a third experiment, which would be replacing the 18650 battery pack we usually use with an EPS (Energy Power System) type solution that we are developing in collaboration with an electronic engineering student at the UB. The idea is that we will be able to donate this device to schools in the future as the first ad-hoc component designed exclusively for HABs.
If you want to know about all the citizen experiments and probes that will be launched in #SERVETVII, visit the selected proposals area.