Micro Controller

Micro controller unit was designed

Supply: 5V@2mA
40MHz clock ~10MIPS
RS232 interface
Humidity sensor input
1 dig input
2 dig outputs

Complete Spark Detection Circuit

Output TTL pulse duration is ~110 ms

Logo

by Jitka

Spark Detection Circuit

Spark Detection Circuit was designed and simulated
RED trace: Output signal
GREEN trace: Spark plug voltage

Required supply voltage is +5V.

Safety charge is 50uC. It's 50uF @ 1000V => 10nF @ 800 V SAFE ENOUGH

There will be a shaping 555 circuit that wasn't simulated.

Ionisation tube

Concept of Ionisation tube and EMC.

Ionisation tube will be an independent module with double shielding. It will have it's own battery power source and all digital I/Os will be insulateted by the ADuM11001. It is a digital isolator based on Analog Devices iCoupler technology. Combining high speed CMOS and monolithic air core transformer technology, this isolation component provides outstanding performance characteristics superior to alternatives, such as optocoupler devices.
The spark plug will be out of the gondola.

#It's a question, where to place the humidity sensor. It should NOT be inside of the Ion. tube, but it can be mounted on it (outside the double shielding).

5V switching power supplies

we still have 2 PCBs for the 5V/2A PS and and can be used for new power supplies. I suggest to use both of them in parallel for back up.

Thermal scan of the TimePix

The thermal camera cannot be moved from the CTU. We have to move the TimePix to my office. Waiting for approve from the IAP.

New chapter for the SED

abut the thermal design was written and distributed for comments.

Thermal scan

HV Power source

HV source was designed and simulated. HV is ~900V (stabilized and adjustable).

Old Timepix Experiment

moved to my office at CTU. Without Medipix detector.

Spark initialization voltage dependence on initial Ion concentration

We found out that there is obvious dependence of Spark initialization voltage on initial Ion concentration. The detailed feasibility study of the ionization concentration in the range of altitudes requested is ongoing, results to be provided in the range of interest. Concerning the BEXUS7 floating altitude of 27km, the ambient pressure was 19Pa, Resp. BEXUS6 at floating 30km with 10Pa.
Therefore 10Pa is the relevant minimum for our experiment, with start of relevant function of our ionization tube function above 10km of altitude, with ambient pressure of 20kPa. Dependence plots of temperature and pressure coming soon.

Tests

A thermal camera for thermal design at CTU is available. EMC test of the ionization tube has to be prepared.

New log book

New log book was created