projects:hadie
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projects:hadie [2010/06/19 12:33] – fsphil | projects:hadie [2011/01/29 00:21] – [Third Flight] fsphil | ||
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* C328-7640 JPEG Camera Module ([[http:// | * C328-7640 JPEG Camera Module ([[http:// | ||
* Takes fairly good images up to 640x480, but because of the slow data link it will only be used at 320x240. All of the JPEG compression is done on-board the camera so is ideal for using with a lower power microcontroller, | * Takes fairly good images up to 640x480, but because of the slow data link it will only be used at 320x240. All of the JPEG compression is done on-board the camera so is ideal for using with a lower power microcontroller, | ||
+ | |||
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* Reed-solomon encoder / decoder. See: [[code: | * Reed-solomon encoder / decoder. See: [[code: | ||
* Modified version of dl-fldigi http:// | * Modified version of dl-fldigi http:// | ||
+ | * The flight software is at http:// | ||
===== Thoughts and Ideas ===== | ===== Thoughts and Ideas ===== | ||
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The payload was spinning for most of the flight causing the signal to fade in and out. Because of this about 5% of image blocks where lost which unfortunately resulted in most of the images being incomplete. Once a block is lost, any subsequent data received for that image is also lost. | The payload was spinning for most of the flight causing the signal to fade in and out. Because of this about 5% of image blocks where lost which unfortunately resulted in most of the images being incomplete. Once a block is lost, any subsequent data received for that image is also lost. | ||
+ | Images from the main and uart cameras can be seen here: http:// | ||
+ | ===== Second Flight ===== | ||
+ | A second flight was made on the 9th January 2011. Using much of the same hardware as the previous flight, its main job was to test the improved SSDV error recovery code. Most of the components survived the last flight and where reused for this one. The main differences where: | ||
+ | * Interrupt driven RTTY code with a single pin and two resistors. (3.3v -> 330 ohm -> NTX2 tx pin <- 2.2k ohm <- rtty output pin) | ||
+ | * The new robust image format, a lost packet will not ruin the rest of the image. See the [[guides: | ||
+ | * Quarter-wave dipole antenna, mounted so that the module doesn' | ||
+ | * Canon A560 camera with CHDK and script to take regular images. | ||
+ | * A new version of the C328 UART camera with a wide-angle lens. | ||
+ | * A thicker polystyrene box with compartments for each of the components, wrapped in foil backed polystyrene sheets. | ||
- | ===== Second | + | The balloon was released at 12:17 UTC and began heading east almost immediately. Reception on the small vertical became difficult within about five minutes of release, so we switched to using the stacked yagi array. Even with this the signal was fading fast and the last string to be fully decoded was at 13:09 UTC. There was enough time to receive three full images and fragments of a few more. Contact was re-established by G4FVP and M0DTS at 14:58, almost two hours later! By now the payload was descending and had stopped sending images. The last known position, taken from incomplete telemetry by G4FVP was at 54.383, -2.03966 from about 1300 metres up. The predicted landing spot was 54.3629, -1.88296: |
- | A second | + | |
+ | {{: | ||
+ | |||
+ | M0DTS/Rob went to the area but no signal was received. The payload may have been damaged on landing or the hills could have blocking the already weakened signal. I don't know yet what happened to make the signal so weak, but there' | ||
+ | |||
+ | The highest altitude was received by M0DTS from incomplete telemetry, and was 30217 metres at 14:36:09. M0DTS also reported a likely burst at ~14:51 and with a 3.5m/s ascent rate puts the burst altitude at roughly 33.3km. | ||
+ | |||
+ | The flight code for Hadie-2 is available here: http:// | ||
+ | ===== Third Flight ===== | ||
+ | A third flight is planned for early-March 2011. The plan this time is: | ||
- | * Interrupt driven RTTY code with a single pin. | + | * A proper PCB instead of strip-board. [Maybe] |
- | * The huffman and quantisation tables will be filtered from the JPEG images before transmission. The C328 camera appears to use fixed tables which can be re-inserted into the image after reception. | + | * Add a 16-bit checksum to the SSDV packet structure. [Done in github, being tested] |
- | * Quarter-wave dipole antenna. | + | * Use 7-bit Reed-Solomon error correction on the telemetry strings. |
- | * Canon A560 camera with CHDK and script | + | * Have dl-fldigi configured to use a narrower filter width. |
+ | * Fixed a trivial bug that caused the baud rate to be slower than expected. [Done] | ||
+ | * Switch to a low power mode after landing. | ||
+ | ==== Antenna ==== | ||
- | Despite | + | I plan to use a 1/4 wave vertical again, but made in the style of the bazooka vertical used on the first flight. The end of the coax will be stripped back 1/4 wavelength, with the outer shield folded back and split into the four radials. To help keep the antenna from flexing |
projects/hadie.txt · Last modified: 2011/07/10 18:54 by fsphil