Reach Out and Touch Your Next Project with Long Range RC Controller

RC01

Long range wireless control of a project is always a challenge. [Mike] and his team were looking to extend the range of their current RC setup for a UAV project, and decided on a pair of Arduino mini’s and somewhat expensive Digi Xtend 900Mhz modems to do the trick. With a range of 40 miles, the 1 watt transceivers provide fantastic range. And paired with the all too familiar Arduino, you’ve got yourself an easy long range link.

[Mike] set the transmitter up so it can plug directly into any RC controller training port, decoding the incoming signal and converting it into a serial data package for transmitting. While they don’t provide the range of other RF transmitters we’ve seen, the 40 mile range of the modem’s are more than enough for most projects, including High Altitude Balloon missions.

The code for the Arduino transmitter and receiver sides is available at their github. Though there is no built-in error correction in the code, they have not had any issues.  Unfortunately, a schematic was not provided, but you should be able to get enough information from the images and datasheets to construct a working link.

 

Nearspace Environmental Chamber

vacuum

If you’re going to send some hardware up to 100,000 feet, where atmospheric pressure is 1% of what we enjoy on the surface and temperatures swing down to where Fahrenheit and Celsius don’t matter anymore, you might want to do a bit of testing to make sure everything works before launch. With a few bits of PVC, though, that’s a piece of cake.

There were several environmental conditions to take into consideration; the near vacuum experienced by high altitude balloons would be replicated by a refrigerator compressor, the increased solar flux is simulated by a light bulb, and the cold temperatures provided by a chunk of dry ice.

For a proper high altitude, low temperature environmental chamber the test payload should be cooled down via radiation with tubes filled with liquid nitrogen embedded in the walls. This is the NASA way of doing things, but for the budget of $200, [arko]‘s chamber simulates a high altitude environment just fine.

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Launching a balloon and not landing in the ocean

In just a few short hours, the Yale Undergraduate Aerospace Association will launch their 4th high altitude balloon project into the rarefied air of the stratosphere and with any luck bring back pictures of the view high above Connecticut  Long Island, Rhode Island, and Martha’s Vineyard.

Inside their surprisingly strong unibody chassis is two GoPro cameras and a triple-redundant telemetry system consisting of a custom radio system capable of transmitting over 40 miles, a cell-phone based comms system and a SPOT satellite tracker.

There is one very large problem the Yale Aerospace team has had to cope with; Because they’re launching their Skyview balloon from the eastern seaboard of the US, it’s very likely their payload could end up taking a drink in the Atlantic. To solve this problem, the team developed a novel cut-down solution: a piece of nichrome heater wire is wrapped around the line tying the payload to the balloon. If the hardware receives a signal from the ground, or has a software problem, or runs out of battery power, the nichrome circuit will release the balloon from its launch vehicle to hopefully return it to solid ground.

The Yale Aerospace team has also written a custom iOS app allowing the chase cars to track the balloon in real time – a great feature if you’re trying to communicate with several cars going down the highway. You can check out the live data from the balloon on the Yale Aerospace tracking site or just head over to their twitter to read the latest news about the flight.

Checking out Mount Olympus from 38 km

The image above shows Mount Olympus in the center, with a tiny bit of the western suburbs of Thessaloniki, the second largest city in Greece, in the lower right hand corner. These two points are 70 kilometers apart, but we’re not seeing a picture taken from the International Space Station. This is a picture from the SlaRos project, a high altitude balloon launched last summer that ascended to 38 kilometers above Greece.

On SlaRos’ project page (Facebook warning), the team covers the hardware that went in to lofting a camera high above the cruising altitude of commercial airplanes. A GPS module tracked the balloon in real time and relayed this to a GSM module to the mobile command and tracking team.

There are a ton of high altitude pictures of Greece over on the project’s Facebook page as well as a time lapse video of the Grecian wilderness after the SlaRos payload landed. The payload spent a full night in a field before it was recovered, but we’re very glad the team was able to recover these awesome pictures.

Sending a Raspberry Pi to 130,000 feet

We knew this wouldn’t take long. [David] sent a high altitude balloon into the upper atmosphere last weekend using a Raspberry Pi as the brains of the payload.

[David]‘s payload consisted of a Raspberry Pi, natch, with a Logitech webcam, GPS receiver, and six AA batteries wired into a LDO regulator with a monstrous heat sink to keep everything in the EPX foam enclosure relatively warm in the frigid rarefied air of near space.

A high altitude balloon isn’t much fun without some real-time data coming down from the upper atmosphere, so [David] used a Radiometrix NTX2 transmitter module (anyone know of an equivalent part for the USA?) that transmits a measly 10 milliwatts. Even though the transmitter has an ‘official’ range of 500 meters, [David] got word of image data being received in Northern Ireland, over 500 km away.

We’re pretty impressed with [David]‘s flight  - and the fact that his flight is now 12th place on the list of UK balloon altitude records – but now we’re wondering what could be done with another Raspi flight to near space. [David] had a lot of computing horsepower up there, enough to get images from a webcam and send them down to earth. Now we’re wondering what else could be done with a Raspberry Pi in space.

You can check out the GoPro video of the very fast decent after the break, or check out the received images on [David]‘s Flickr.

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Beating the wrong amateur balloon record

Friday, we covered a little project that attempted to beat the UK altitude record for an amateur balloon launch. Things don’t always go as planned, but the APEX team did manage to beat the several other UK records, including ones for the longest distance and flight duration for a latex balloon.

The APEX team was originally trying to beat the altitude record set by [Darkside] and his Horus 15.5 payload that made it to 40,575 meters. The APEX balloon was launched and slowly climbed over the North Sea to the expected burst point. Unfortunately for the trackers, the balloon leveled off at about 36km and just kept going.

The total Great Circle distance of the APEX Alpha flight was 1347km, with a total flight time of 12 hours, 20 minutes. The balloon eventually drifted out the radio range of anyone aware of the project. Despite the valiant efforts of HAMs across Europe, APEX Alpha was lost in the “HAM wastelands of Eastern Europe,” somewhere over Poland.

Even though the APEX team lost contact with their balloon, Alpha was still transmitting at the time. The balloon surely burst at this point, so it could have landed anywhere from Poland to Ukraine to Russia. The APEX team is offering a reward for finding Alpha, so if you see a small styrofoam box in Eastern Europe, drop the APEX boys a line.

Of course this flight couldn’t have taken place without the efforts of HAMs across Europe. [Darkside], [2E0UPU], and so many others helped out with the tracking as Alpha passed over the Netherlands and continued towards Berlin. The last contact was made by the awesome [OZ1SKY], who was very gracious to stay up until the wee hours of Sunday morning.

Not a bad flight for something that was supposed to take a swim in the North Sea. If you’d like to see the raw data from the flight, the APEX team posted everything they pulled down.

Going for the amateur balloon altitude record

At 11 AM London time, October 22, the Sutton grammar school for boys is going to be launching Apex Alpha, a high altitude amateur balloon for an attempt at the UK altitude record. Unlike a few other balloons we’ve seen, the Apex team is doing it right and giving everyone the downlink details for the balloon.

The payload for the balloon was built entirely by student of the Sutton grammar school and weighs less than 300 grams. While it’s not carrying a camera for the all-important pretty pictures, the payload does have a GPS module and a transmitter; it’s just enough to do the required testing on the lead up to Apex III.

Right now, the UK amateur balloon record stands shy of 130,000 feet. The team gained a lot of experience with their Apex I and Apex II launches, and they’re pretty confident they have the experience to pull this one off. You can check out the progress of the Apex Alpha flight on the spacenear.us tracker. For us Yanks, the launch should start October 22nd at 6:00 am Eastern time and 3:00 in the morning for the West coast. The team says they’ll be updating that throughout the flight.

UPDATE: Apex Alpha just won’t burst. Any HAMs near Berlin in Eastern Europe are sorely needed. Head over to the IRC chat if you can help.