Ava High Altitude Balloon Project

One of the major stumbling blocks for HABing is the components we use are generally available in surface mount and are expensive to obtain in small quantities. With the Falcom FSA03 now end of life options for HABers are limited. To fill this gap I’ve created an online store, HAB Supplies.

I’ve designed a number of breakout boards for the uBLOX MAX-6 GPS Chip allowing easy soldering to the surface mount components :

The one on the right is fitted with the Sarantel SL-1202 antenna on 1.6mm PCB, the one on the right is the “pico” version constructed on 0.8mm PCB and using a chip antenna. The store offers the individual components for you to solder or you can purchase boards that are presoldered so you can just get on with making your project with out worrying about destroying the GPS chip.

Its worth noting these boards only run at 3.3V so you will need some sort of level conversion to use them with Arduinos or PC serial (suitable part http://www.sparkfun.com/products/8745 ).

I do plan to make a board with the level convertors on them so you can utilise them natively with an Arduino, watch this space. In the mean time if you do want any components I’m sure you’ll find the prices extremely competitive.

Resolved the issue with the NTX2 not transmitting properly, seems I’ve got the pins wrong in the code, the hardware is fine. However the part I chose for the onboard temp sensor was wrong so currently no on board temp sensor, though the external one works fine:

I then powered it up and popped it in my pocket and took the dog for his evening walk, the uBLOX6 is extremely accurate, its fairly clear exactly which side of the road I was on (click for larger) :

Amazingly despite getting the wrong voltage regulators and putting 6V through a GPS rated at 3V, and then making a mess of the soldering the GPS chip appears to be in tact. I connected up the serial pushed the code to it and it fired up immediatly, the pink LED’s blinking as it transmitted each bit. Also success 2 the Swift boards we’ve been working on also worked yay ! Here is Swift and Ava next to each other. Tommorrow I’ll get the temp sensors and radio on Ava. Swift gets its GPS.

Started to solder the ‘Block 1’ test board today. Worth testing these boards one step at a time (doubt I’ll be able to remove components once they are on). So I put the AVR, crystal, vreg and assocated resistors and capacitors on the board.

Initial power up the signs weren’t good, no power lights on. However I realised the SMD LEDS were the wrong way round and shortly I had a pink power LED lit. Initial attempts to program the board weren’t sucessful but I brought it home and tried it here and it worked first time.

I think the issue is to use the AVR ISP to program the actual board you need to have the COM port of the ISP <4. Anyway a quick upload later and the board was blinking in wonderful pinkness :

New Rev.2 boards have turned up from www.seeedstudio.com they look fantastic in red :

I’ve popped an NTX2 in there for size reference but they are very small. Just waiting on some parts and then I can get these soldered up.

Just a quick update. I have the proposed board schematic built on breadboard bar the pyro cut down. Generally it all seems to work apart from a nasty buffer overflow that caused all manner of reboots and crashes. It seems occasionally the GPS sends null chars when it doesn’t have a lock, when the Arduino tries to do maths and stuff on nulls a small portal opens  and the world disappears.

Anyway I’ve put some null catching code in there to prevent this and it seems stable now. Whilst trying to right up the pyro circuitry I’ve blow the 3.3v regulator so I need to work out why, the microcontroller and GPS are fortunately ok.

Hopefully once I’ve done with designing the board for Project Swift this weekend I’ll crack on and finish the prototyping off.

The new flight hardware will effectively be an Arduino Pro at its core. As I’m planning on using surface mount chips I won’t be able to use the existing Arduino Duemilanove boards I have to burn the bootloader. So I purchased a Olimex AVR-ISP500. I built the customised Arduino Pro on some prototyping boards and tried to get the bootloader on.

Initially I got alot of errors, a quick hunt round the Arduino forums indicates to get the bootloader to work with the AVR-ISP500 you need to amend programmers.txt in ..\arduino-0023\hardware\arduino :

avrisp.name=AVR ISP
avrisp.communication=serial
avrisp.protocol=stk500v2

Another little trick I discovered is you can program the Arduino using the ICSP programmer. Amend the

C:\Users\<<username>>\AppData\Roaming\Arduino\preferences.txt file and add :

upload.using = avrisp

That done it all works nicely. The board is now running at 3.3v so the GPS is happy. However the crystal I have is a 16Mhz one. I think its leading to some timing errors when using software serial. I switched to New Software Serial which is better but still having a few errors. I’ll switch out the 16Mhz crystal with the correct 8Mhz one shortly.

Test sucessful both modules are sucessfully recieving GPS data within 2 mins of a cold start.

Accuracy is way better than the Inventek modules after being on for an hour there was very little jitter despite being completely indoors :

To testI just used a UM232R :

I’m keeping one, the other is off to assist Nigey as part of Project Swift.

With the salty demise of the Ava1 flight hardware I have a choice. Make another (I have spare components and one spare PCB) or re-design it. The board had a number of flaws and was quite large. I’d planned to re-design it after the first flight anyway. My criteria was smaller, more features and more robust. The Inventek ISM GPS is a bit long in the tooth and I really don’t want to use another antenna patch like the one that failed on Ava1.

Enter the uBLOX 6 NEO and the Sarantel Antenna :

The Sarantel is a helical antenna which is compact and robust and importantly doesn’t move. The uBlox 6 NEO is a brand new very high performance GPS chip. I’ve designed a break board in Eagle for the uBLOX 6 Neo which is on my Github here http://www.github.com/upuaut Look for uBlox_NEO-6Q_Breakout. I have a few spare boards (got 18 made in total) so if you want one give me a shout on #highaltitude.

For your viewing pleasure I present “More Panormas” ! Having sifted through the 2800 pictures and feeding them into Microsoft ICE I’ve done a few more nice composite panoramas. These pictures are a number of individual images joined together to produce an overall picture. The black bits are where there was no photograph or data availble.On all pictures click for bigger.

Firstly, a nice curvature one. Given the direction of the sun I suspect Southern England is on the left and we are looking over Cambridge direction :

Secondly, this is my favorite. The East Anglian coast from Felixstowe down to the South Coast, with France in the distance. Really chuffed the way this turned out, a little washed out due to the lack of a U/V filter. For orientation :

Same location a few thousand feet lower :

And lower still :