Beacon, testing, and more updates!

I took the time off I had over the Christmas break to do a little work on the Balloon project. Over the last two weeks, I've finalized the Beacon, as well as built a TNC-X to assist in tracking the payload.

The beacon consists of an Arduino Uno with a Sparkfun MP3 Player Shield . I used the base of masci10's Sparkfun MP3 Player Shield library to get the mp3 player functional. I'll eventually post up all the code I've used (good and bad) to GitHub and share it with the community. I then created a PTT circuit for the Icom 2AT with 3.5mm stereo  to 1/8" mono cable.

Arduino with MP3 Player Shield (I'm ashamed of the HF electrical tape in this photo. Don't judge me.)

The PTT circuit consists of a transistor connected to pin 10 and ground on the Arduino, and run to a transistor, a capacitor and two pullup resistors on a breadboard. I felt the breadboard would add stability in case of a crash landing. Who knows if I'm correct, but hopefully we won't have to find out.

PTT Circuit

I additionally ran a stress test and had two major successes. The Trackuino ran for over 10 hours on battery before I aborted the test as a success.

The beacon also ran for over 10 hours on battery before I aborted the test as a success.

The ATV transmitter ran for over 5 hours, but unfortunately, the Camera seems to have blown a regulator during the test. I'll get that back up and running and re-test. 

My TNC-X in Operation. Ready to listen for the Balloon.

Update!

I ordered the balloons and parachute. All total (shipped), $218.46. That's for two balloons (in case we pop one, or want to do a second launch) and a 6.5' parachute.

The balloons are from Project Aether (shipped from Amazon). The parachute is from The RocketMan.

The payload plans have been modified a bit to fit everything we want to do, and have redundant failover.
The ATV equipment requires 12v (not 7 as we were going to run), so I picked up a 12v Lithium Ion battery pack. We can now have 12v on board.

I've got 4' of the nichrome wire we're using to cut the payload down. This will be powered by a single 9v battery, as the draw from the nichrome wire could be enough to shut the battery pack down and terminate all other equipment.

We're going to run 3 separate Arduinos, for redundancy and to ensure everything operates smoothly.

The first is the Trackuino, which is currently on the air at Dan - K8PLW's house (http://aprs.fi/#!call=a%2FK8RDM-11).

The second is the beacon transmitter, which is online at my house (minus the transmitter). It's currently outputting to a set of headphones in a 24 hour stress test. This arduino will loop an MP3 transmission endlessly, with a 2 minute pause in between. It also provides a logic high voltage out on one of the pins when it is transmitting so we can key the PTT on the Icom 2AT.

The third is for the DTMF decoder / cut down mechanism. This cut down mechanism is currently in development by John - K8YYZ. He's setting up an MT-8870 to decode the tones and after a multi-tone input (which will be highly classified), trigger a relay for the 9v battery for the cut down mechanism.

Steps still left to complete:

• Finish cut down Arduino.

• GPS out of the Arduino for the ATV team to overlay to the transmitted video signal - I don't think this will be difficult. We have the data in the Trackuino. I may have to defer to K8YYZ, as I wrote my first arduino code last night for the beacon.

• Get Helium.

• Get the ATV Equipment and get it in the payload

• Confirm launch location

• Obtain payload cordage

• Secure and assemble the payload

• Weigh payload all assembled 

• Notify the FAA

I'll be bringing the Beacon, Trackuino, and everything else I can gather to the Hot Dog and Corn Roast for a little show and tell.

Finally, I'm fairly certain there's no way we can make the August 24th date. Things just have not fallen into place as quickly as I'd hoped. I don't have the ATV equipment yet (and won't have time to drive over and pick it up until probably next week). I'll start polling for future dates here shortly.

Calculating Trajectory

There are a number of online trajectory calculators. I've been using this one. My initial guestimate as to where we should launch for a landing in Livonia dumped me right at the edge of Metro Airport... oops. Scratch that one, and just to be on the safe side, let's go a little further Northwest. We have quite a few lakes in our area, so landing is crucial if we don't want to go beg someone to take us out on a boat.

Keeping this in mind, and back tracing, I found a suitable launch site in Gratiot County. There's a few options there, and they all dump us in Oakland county near Waterford. I think that's the best option.

Tentative Launch Date Determined

At this past meeting (Saturday, 6/1/2013) we determined that August 24th, 2013 would be our tentative launch date.

We say tentative, as we still have a LOT of work to do to get this balloon off the ground, and it will be pending weather.

The club is participating in a K8SB Active Attenuator build August 18th, and as that build will lend itself well to finding the payload once it hits the ground, we would like to perform the launch once that build is completed.

We have a number of parts coming in to get construction moving, and we are making good progress at this point. As we get closer to launch day, we'll post more information, including location of launch, calculated trajectory, complete list of parts in use, and beacon frequency / APRS identifiers.

Right now we have a number of isolated systems that are being brought up, and we've got to get them all tied together and working as a single payload unit. We're very excited, and very appreciative to all the members of the Livonia Amateur Radio Club, and non-members who have offered advice and/or equipment to the cause.

Icom 2AT

After charging up the Icom 2AT, and running through some diagnostics, it appears I have purchased a fully working radio. I took it over to Dan Saputo - K8PLW's house while visiting and doing some DStar radio programming. I left it over there, as he has a better workbench to do some payload assembly and testing. Needless to say, with him working nights, he gets bored while everyone is sleeping and began putting a 7808 Voltage Regulator on the bottom. This allows us to directly feed 12 volts from our battery system to the handheld for a beacon & termination setup. We'll just need to work on the DTMF decoding for termination and we'll be done with the beacon / termination system.

Hab-ham.org and general project status

HabHam is a site with forums dedicated towards Ham Radio High Altitude Ballooning. It's an excellent resource for things

They typically use an Arduino and Trackuino for APRS and tracking. We have been planning to use the Byonics MicroTrak AIO for our APRS tracking, but the cost of $320 has been a bit prohibitive. The Trackuino project would cost less than half as much ($120), and John - K8YYZ is an avid Arduino programmer.

I've reached out to a kind member of hab-ham.org who has extra Trackuino shields already printed, and he is shipping me two of them. The rest of the parts for the Trackuino are sourced at the following links

• Mouser BOM for general parts - $13.55 (includes Arduino, which we have, so we can remove that).
• Sparkfun GPS Module for Arduino - $49.95
• RadioMetrix Transmitter - I've emailed the source in the US for this part. Awaiting response. Should be less than $50 actual cost was $70 + shipping. Byonics also sells this part.

In addition, I did some testing with the Baofeng UV5r radio that we were planning on using for our beacon transmitter and termination receiver. Unfortunately, the UV-5r has a time out timer with a maximum value of 5 minutes. This radio generated so much heat that my display turned purple after a 2 minute transmission at it's lowest power setting, and started dropping transmissions. The plan of running the beacon on 5 minutes, off 1 minute (for DTMF termination) is therefore not an option with this radio. 

After discussing this with K8PLW - Dan Saputo, I ordered an Icom 2AT handheld used from Ebay. This radio cost me $40, and is known for it's ruggedness. This can be a sacrificial radio that we can gut out what we need. and utilize it for this project.

Radar Reflector

Reading about the Apteryx High Altitude Balloon project, they mention they used a Radar Reflector from West Marine. We had intended to build our own radar reflector out of some plastic and aluminum tape. For $28, the reflector may hold up better to the extreme measures of space if we use a commercially built reflector.