{"id":1943,"date":"2016-05-31T20:37:21","date_gmt":"2016-05-31T20:37:21","guid":{"rendered":"http:\/\/www.daveakerman.com\/?p=1943"},"modified":"2016-05-31T20:44:10","modified_gmt":"2016-05-31T20:44:10","slug":"1943","status":"publish","type":"post","link":"http:\/\/www.daveakerman.com\/?p=1943","title":{"rendered":"To Zero, And Beyond"},"content":{"rendered":"<p>As many reading this will know, I flew the new Pi Zero on the day it was announced, in order to test a prototype of our new PITS-Zero tracker board. \u00a0I&#8217;d been pleading with Eben since I first saw a prototype of the original Pi Zero, that its low weight would be\u00a0ideal for live-imaging HAB applications, if only it had a camera port. \u00a0The camera is much the entire reason for using a Pi for HAB &#8211; if you don&#8217;t want pictures then a smaller\/lighter\/simpler AVR or PIC microcontroller will easily do the job (and with less battery power) &#8211; so I felt that the CSI-less Pi Zero was a missed opportunity. \u00a0Eben agreed, and said he would try to make it happen.<\/p>\n<p><img decoding=\"async\" loading=\"lazy\" class=\"aligncenter size-full wp-image-1947\" src=\"http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/PiZero1.3_700.jpg\" alt=\"PiZero1.3_700\" width=\"700\" height=\"424\" srcset=\"http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/PiZero1.3_700.jpg 700w, http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/PiZero1.3_700-300x182.jpg 300w\" sizes=\"(max-width: 700px) 100vw, 700px\" \/><\/p>\n<p>So, when I received a sample Pi Zero with CSI port, I was keen to try it out. \u00a0However launching an unreleased device, to possibly parachute down in front of a curious Pi fan, might not be the best idea in the world, so I had to wait. \u00a0Fortunately the wind predictions were good for a balloon launch on the Pi Zero CSI launch day, and the flight went well albeit the burst was rather lower than predicted (balloons vary).<\/p>\n<h1>Sony Camera<\/h1>\n<p>I had hoped to fly the new Sony camera for the Pi, but in testing the camera would become invisible to raspistill after about 2 hours and roughly 2-300 photos. \u00a02 hours isn&#8217;t long enough for a regular flight, and mine was expected to take more than 3 hours just to ascend, so this wasn&#8217;t good. \u00a0I searched the Pi forum and found that a couple of people using time-lapse photography had found the same issue, and as it was a new issue with no fix or workaround yet, I had to opt for the Omnivision camera instead. \u00a0This of course gave me a reason to fly the same tracker again as soon as there was a solution for the Sony firmware issue; once there was I tested it, and planned my next flight.<\/p>\n<h1>Waiting For Baudot<\/h1>\n<pre><em>\"It's currently a problem of access to gigabits through punybaud\"\r\n<\/em><\/pre>\n<p>I&#8217;ve written\u00a0<a href=\"http:\/\/www.daveakerman.com\/?p=1913\">previously<\/a>\u00a0about LoRa, but the key points about these Long Range Radio Modules when compared to the old (first used from the air in 1922) RTTY system are:<\/p>\n<ul>\n<li>Higher data rates<\/li>\n<li>Longer range with the same rate\/power<\/li>\n<li>Can receive as well as transmit<\/li>\n<li>Low host CPU requirements even for receiving<\/li>\n<\/ul>\n<p>The higher data rates mean that we can send larger images more quickly (throughput is up to 56 times that of 300 baud RTTY), and the receiving capability makes it easy to have the payload respond to messages sent up from the ground. \u00a0For this flight, those messages are used to request the tracker to re-send any missing packets (ones that the receiving stations didn&#8217;t hear), thus reducing the number of annoying missing image sections down to about zero. \u00a0To give you an idea of the improvement, the following single large picture was sent in about a quarter of the time taken by the\u00a0inset picture (from my first Pi flight, and at the same pixel scale):<\/p>\n<p><img decoding=\"async\" loading=\"lazy\" class=\"aligncenter size-large wp-image-1949\" src=\"http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/progress-1024x768.jpg\" alt=\"progress\" width=\"640\" height=\"480\" srcset=\"http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/progress-1024x768.jpg 1024w, http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/progress-300x225.jpg 300w, http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/progress-768x576.jpg 768w, http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/progress.jpg 1280w\" sizes=\"(max-width: 640px) 100vw, 640px\" \/><\/p>\n<h2>LCARS Chase Car Computer<\/h2>\n<p>For this flight, I tried out my new chase-car computer. \u00a0This has a Pi B V2, Pi touchscreen, LoRa module, GPS receiver and WLAN (to connect to a MiFi in the chase car). \u00a0The user interface mimics the Star Trek LCARS panels, and was written in Python with PyQt. \u00a0It receives telemetry both locally (LoRa, or RTTY via a separate PC) and also from the central UKHAS server if connected via GSM.<\/p>\n<p><iframe loading=\"lazy\" width=\"640\" height=\"360\" src=\"https:\/\/www.youtube.com\/embed\/X3et45cx_ZM?feature=oembed\" frameborder=\"0\" allowfullscreen><\/iframe><\/p>\n<h2>The Flight<\/h2>\n<p>As per the previous Pi Zero flight, this was under a 1600g balloon filled with hydrogen. \u00a0Predicted burst altitude was 42km, and I hoped that this time it might achieve that! \u00a0The payload was the same as last time:<\/p>\n<p><img decoding=\"async\" loading=\"lazy\" class=\"aligncenter size-large wp-image-1951\" src=\"http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/image-768x1024.png\" alt=\"image\" width=\"640\" height=\"853\" srcset=\"http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/image-768x1024.png 768w, http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/image-225x300.png 225w, http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/image.png 900w\" sizes=\"(max-width: 640px) 100vw, 640px\" \/><\/p>\n<p>except of course for the new Sony camera (manually focused for infinity, but not beyond) and a new set of batteries.<\/p>\n<p>On the launch day the weather was overcast but forecast to improve a little, so I decided to wait for a gap in the clouds. \u00a0When that came, the wind did too (that wasn&#8217;t forecast!), which made filling the balloon interesting.<\/p>\n<figure id=\"attachment_1952\" aria-describedby=\"caption-attachment-1952\" style=\"width: 720px\" class=\"wp-caption aligncenter\"><img decoding=\"async\" loading=\"lazy\" class=\"size-full wp-image-1952\" src=\"http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/13315254_10154383887897259_5398784479148600136_n.jpg\" alt=\"No my head hasn't turned into a giant clove of garlic\" width=\"720\" height=\"960\" srcset=\"http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/13315254_10154383887897259_5398784479148600136_n.jpg 720w, http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/13315254_10154383887897259_5398784479148600136_n-225x300.jpg 225w\" sizes=\"(max-width: 720px) 100vw, 720px\" \/><figcaption id=\"caption-attachment-1952\" class=\"wp-caption-text\">No my head hasn&#8217;t turned into a giant clove of garlic<\/figcaption><\/figure>\n<p>Fortunately, the wind did drop for launch, and the balloon ascended towards the gap I&#8217;d mentioned in the clouds:<\/p>\n<p><img decoding=\"async\" loading=\"lazy\" class=\"aligncenter size-large wp-image-1953\" src=\"http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/P1110657-1024x768.jpg\" alt=\"P1110657\" width=\"640\" height=\"480\" srcset=\"http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/P1110657-1024x768.jpg 1024w, http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/P1110657-300x225.jpg 300w, http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/P1110657-768x576.jpg 768w\" sizes=\"(max-width: 640px) 100vw, 640px\" \/><\/p>\n<p>The LoRa system worked well (especially once I remembered to enable the &#8220;missing packet re-send&#8221; software!), with the new camera acquitting itself well. \u00a0I used ImageMagick onboard to apply some gamma to the images (to replace contrast lost in the atmosphere) and to provide a telemetry overlay, including this one which I believe is the highest image sent down live from an amateur balloon.<\/p>\n<p><img decoding=\"async\" loading=\"lazy\" class=\"aligncenter size-large wp-image-1954\" src=\"http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/Cjaear8WEAA1ENN-1024x773.jpg\" alt=\"Cjaear8WEAA1ENN\" width=\"640\" height=\"483\" srcset=\"http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/Cjaear8WEAA1ENN.jpg 1024w, http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/Cjaear8WEAA1ENN-300x226.jpg 300w, http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/Cjaear8WEAA1ENN-768x580.jpg 768w\" sizes=\"(max-width: 640px) 100vw, 640px\" \/><\/p>\n<p>Burst was a few metres later, comfortably beating my previous highest live-image flight.<\/p>\n<p>And this was the last image it sent. \u00a0I guessed why. \u00a0Remember the camera stuck to the outside? \u00a0My guess was that after burst &#8211; when the payload suddenly finds itself without support &#8211; the line up to the balloon found its way behind the camera which it then removed as the balloon remnants pulled on it. \u00a0So, I can&#8217;t show you any images from the descent, but I can show you this shot of the Severn Estuary\u00a0(processed to improve contrast) from the ascent:<\/p>\n<p><img decoding=\"async\" loading=\"lazy\" class=\"aligncenter size-large wp-image-1955\" src=\"http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/15_20_48_shopped-1024x769.jpg\" alt=\"15_20_48_shopped\" width=\"640\" height=\"481\" srcset=\"http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/15_20_48_shopped-1024x769.jpg 1024w, http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/15_20_48_shopped-300x225.jpg 300w, http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/15_20_48_shopped-768x577.jpg 768w\" sizes=\"(max-width: 640px) 100vw, 640px\" \/><\/p>\n<p>In the chase car, I stopped at a point with a good view towards the landing area, so I could get the best (lowest) last position I could. \u00a0With the payload transmitting both LoRa and RTTY, I had my LCARS Pi receiving the former, and a Yaesu 817 with laptop PC receiving the latter. \u00a0With no images, the LoRa side dropped to sending telemetry only, which was handy as I was able to receive a lot of packets as the balloon descended.\u00a0Overall LoRa seemed to be much more reliable from the car than RTTY did, despite the much higher data rate, and I now would be quite happy to chase a balloon transmitting high bandwidth LoRa and nothing else.<\/p>\n<p>With the final position logged, I carefully tapped that into the car sat nav and then drove off to get the payload back. \u00a010 minutes later I remembered that I&#8217;d coded exactly that function into my LCARS program! \u00a02 screen-taps later, I had on-screen navigation (via Navit); I would also have had voice navigation but I hadn&#8217;t connected a speaker yet.<\/p>\n<p>Both Navit and the car sat nav took me to a hill with the payload about 300 metres away. \u00a0I waited for another HABber to arrive &#8211; his first time chasing &#8211; and meantime I updated the other enthusiasts online, and took some photographs of the scenery; Shropshire is very pretty.<\/p>\n<p><img decoding=\"async\" loading=\"lazy\" class=\"aligncenter size-large wp-image-1959\" src=\"http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/P1110661-1024x768.jpg\" alt=\"P1110661\" width=\"640\" height=\"480\" srcset=\"http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/P1110661-1024x768.jpg 1024w, http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/P1110661-300x225.jpg 300w, http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/P1110661-768x576.jpg 768w\" sizes=\"(max-width: 640px) 100vw, 640px\" \/><\/p>\n<p>Once Andy arrived, we walked down to the payload, watched (as often the case) by the local populace:<\/p>\n<figure id=\"attachment_1961\" aria-describedby=\"caption-attachment-1961\" style=\"width: 640px\" class=\"wp-caption alignnone\"><img decoding=\"async\" loading=\"lazy\" class=\"wp-image-1961 size-large\" src=\"http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/P1110662-1024x768.jpg\" width=\"640\" height=\"480\" srcset=\"http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/P1110662-1024x768.jpg 1024w, http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/P1110662-300x225.jpg 300w, http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/P1110662-768x576.jpg 768w\" sizes=\"(max-width: 640px) 100vw, 640px\" \/><figcaption id=\"caption-attachment-1961\" class=\"wp-caption-text\">Ewe Looking At Me ??<\/figcaption><\/figure>\n<p>As expected, the camera was missing, so if anyone wants a free Sony Pi camera, I can give you a 5-mile radius area to search.<\/p>\n<figure id=\"attachment_1960\" aria-describedby=\"caption-attachment-1960\" style=\"width: 640px\" class=\"wp-caption aligncenter\"><img decoding=\"async\" loading=\"lazy\" class=\"wp-image-1960 size-large\" src=\"http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/P1110664-1024x768.jpg\" alt=\"P1110664\" width=\"640\" height=\"480\" srcset=\"http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/P1110664-1024x768.jpg 1024w, http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/P1110664-300x225.jpg 300w, http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/P1110664-768x576.jpg 768w\" sizes=\"(max-width: 640px) 100vw, 640px\" \/><figcaption id=\"caption-attachment-1960\" class=\"wp-caption-text\">You don&#8217;t need CSI to see what went wrong here &#8230;<\/figcaption><\/figure>\n<p>A lot of the balloon was still attached, which helps to explain how the camera was forcibly removed:<\/p>\n<p><img decoding=\"async\" loading=\"lazy\" class=\"aligncenter size-large wp-image-1962\" src=\"http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/P1110665-768x1024.jpg\" alt=\"P1110665\" width=\"640\" height=\"853\" srcset=\"http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/P1110665-768x1024.jpg 768w, http:\/\/www.daveakerman.com\/wp-content\/uploads\/2016\/05\/P1110665-225x300.jpg 225w\" sizes=\"(max-width: 640px) 100vw, 640px\" \/><\/p>\n<p>So, a nice flight and recovery. \u00a0The Sony camera worked well; 868 LoRa worked well; the LCARS chase car tracker worked well. \u00a0Next time, more duct tape!<\/p>\n","protected":false},"excerpt":{"rendered":"<p>As many reading this will know, I flew the new Pi Zero on the day it was announced, in order to test a prototype of our new PITS-Zero tracker board. \u00a0I&#8217;d been pleading with Eben since I first saw a prototype of the original Pi Zero, that its low weight [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[4],"tags":[],"_links":{"self":[{"href":"http:\/\/www.daveakerman.com\/index.php?rest_route=\/wp\/v2\/posts\/1943"}],"collection":[{"href":"http:\/\/www.daveakerman.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.daveakerman.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.daveakerman.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.daveakerman.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1943"}],"version-history":[{"count":10,"href":"http:\/\/www.daveakerman.com\/index.php?rest_route=\/wp\/v2\/posts\/1943\/revisions"}],"predecessor-version":[{"id":1965,"href":"http:\/\/www.daveakerman.com\/index.php?rest_route=\/wp\/v2\/posts\/1943\/revisions\/1965"}],"wp:attachment":[{"href":"http:\/\/www.daveakerman.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1943"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.daveakerman.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1943"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.daveakerman.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1943"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}