HAB

I built the “fill tube” following ideas of this UKHAS wiki page. As I don’t have something to create a grove, I used a PVC waste water plug that already have some kind of grove by design. I strongly glued the flexible fill on it. To close the remaining space, I added some wet newspaper sheets to create a temporary “wall”. I used a hot glue gun, and let the hot glue fall all around the both sides of the newspaper.

The payload had a backup transmission using a USB 3G/SMS dongle (Second hand / 10€) to send SMS with coordinates in case of failure of the NTX2. As it is useless (no signal in altitude) and waste of battery to power the USB dongle during all the flight, I used a script to power it (using a GPIO and a relay) only when the payload was back near the ground (altitude back bellow 2 Km).

Introduction We previously get some data collected by Habitat server, but in this post, we are using Gnuplot to plot our data. This is data that has been stored on the payload, not the data sent to Habitat server during the flight. Data sent during the flight do not contain: Data for every minutes of the flight Data about some sensors (like pressure) To have my files in the same time zone as Habitat, I subtracted 1 hour with date command as bellow:

Description Payload has been launched with 2 DS18B20 temperature sensor. One was inside and another one outside the payload. There are several ways to “study” graph. One easy way is to use data from Habitat available on on x-f.lv External temperature Lower value was -40°C around 10 000 meters. (And possibly after burst) Temperature drop again when the payload is falling very fast after drop. As it is data from Habitat, not the payload itself, there are some missing data.

Who received the UGGY payload signal ? This data can be extracted from Habitat Server CallSign Location Other Min altitude Max altitude G8DHE Worthing, West Sussex, UK Website 14 150 30 076 PE2G Netherlands 25 164 33 506 jijdaar Netherlands 23 047 30 076 PB0AHX Netherlands Website 27 472 33 632 RAGONDIN French chase car Scottish operator ;) ~ 120 33 130 Uggy French chase car website ~ 120 2 811 (then moved as driver) Great to have listeners outside France !

Description The NTX2 is a transmitter on the 434MHz frequency. As seen in previous post, this frequency can be used without licence in most of Europe. NTX2 power is 10mW wich is authorised in the sky. According to the documentation, NTX2 is supposed to transmit only to 500m, but with good line of sight, signal can be received from the sky at more that 40Km. NTX2 is transmiting by applying a voltage on it’s TXD pin.

Introduction dl-fldigi is a modified version of Fldigi to add some features related to HAB. dl-fldigi use sounds created by Gqrx (see previous post) to decode informations sent from the balloon, then is able to send these informations on a server on Internet. If a request has been made, it will display the balloon on the map. What is great, is the decoded packets can been sent by anyone, not only the owner of the balloon.

Introduction SDR (Software Defined Radio) is a radio communication system where components that have been typically implemented in hardware (e.g. mixers, filters, amplifiers, modulators/demodulators, etc…) are instead implemented by means of software on a personal computer. The main advantage of SDR is the low cost. In France (and many countries in Europe), we are free to use the 433MHz frequency (433,050 à 434,790 MHz). This way we could be able to receive signal sent from the balloon, then decode the signal to get the coordinates etc…

The flight is available on video (timelapse of best pictures assembled with music) Size: 58MB Time: 2m56s Music (CC BY-NC-SA 3.0) : Antony Raijekov / Lightin Download video Mkv file created with the folowing command: $ mencoder mf://*.jpg -mf fps=1:type=jpg -ovc x264 \ -x264encopts bitrate=2400:threads=2 -o outputfile.mkv -oac copy \ -audiofile /home/yannick/Antony_Raijekov_-_Lightin.mp3 Download video / 2nd version Mp4 file created with the folowing command: $ fmpeg -i music.mp3 -r 1 -i img%04d.

Payload The payload is made with foam, then protected with flashy orange tape for maximum visibility (in the air, and on the ground). A label explaining it is harmless, with contacts details, is outside and inside the box. The payload contains: Raspberry Pi Model A Some unused connectors have been removed (RCA..) Running Raspbian MicroSD 8GB SD to microSD adapter to limit the risk of the regular SD to be moved away of the slot.