Thermal Wake at High Altitudes

Electrical Design

We used a custom made pcb made by a student here at Whitworth. It uses a breakout for the mbed micro controller which allows for easy access to plug in a micro SD card reader and a simpler way to create circuit. We had two arms and a tail in an attempt to get our sensors far enough away from the balloon to detect both the normal temperature and the temperature change caused by the thermal wake.


 * Inputs

We used a total 54 D1820 temperature sensors soldered together in parallel. The sensors were split between three wires, two for the arms of the pod and one for the tail. Each set of sensors was connected to the main bread board with three connections; positive, ground, and signal. Each signal wire has a 4.7 kiloohm resistor used as a pull up resistor. This resistor changes the voltage in the sensors allowing use to effectively read the DS1820s.


 * Reconstructing the Arms/ Tail Wires

The wires for the arms/ tails from the previous year were left in bad conditions with broken wires and weak connections to the temperature sensors. We ended up unsoldering all the temperature sensors from the wires and used a new approach for re-soldering them. We ended up using connectors and soldered those directly the wire to allow for easy attachment and removal of the temperature sensors. This way we can take out the temperature sensors without having to de-soldering them which saves time and resources. We used this system for all the wires for both the arms and tails.