Battery test complete

I ran the video camera and arduino temperature logger attached to a 8pack of alkalines until it drained them. Got about 5 hours of logging data on the arduino. The camera made two files. The first was two hours long and fine, the second was corrupted. I'm hoping this was just because the battery failed during a write to the card. The lithiums will last even longer and I don't expect it to be recording longer then 2 1/2 to 3 hours. So we should be good. I hope.

The only test left is to double check the gps module and make sure I can receive and track it from my laptop/car. After that we should be good to go, just need to pick a date and reserve the helium tank.

Balloon payload complete

Mark and I worked on finishing the balloon payload yesterday. We mounted the camera, covered the outside of the package with florescent paper (to increase visibility) and mounted everything inside. We came in right under a kilogram minus rigging & parachute. That is pretty close to ideal.

We also pre-filled a water jug with 1666grams which is what we worked out should be the weight (with the addition of the filling nozzle) to equal the appropriate total lift of the balloon when filling. i.e. when the balloon just is able to lift the weight, we have it filled to the proper amount.

The only thing left is some testing. I need to double check the tracking ability of the gps in my car by 'chasing' the gps module in another car.

I also need to make another battery test of the camera since the arduino temperature logger is pulling off of the same battery pack. I plan on plugging the power into an outlet first to double check that the camera will record past 1 2gig file. Then after I confirm the camera does that I'll run through a alkaline battery pack to make sure the recording time is sufficient.

It lives!

After some Frankenstein wiring, I've created the balloon-ready temperature logger. Its not quite as small as I would like, partially because of the SD shield which is designed to plug into a full size arduino, hence takes up some space. I don't think I could have gotten it smaller without stacking the components, which would have made the wiring even harder.

The 'external' temperature probe is located on the end of the wire in the picture. The 'internal' one is soldered onto the board (at the back of the picture)

Arduino nano is back left, Real Time Clock is back right, and the SD module is in the forefront.

Temperature Logging Working!

I've gotten the temperature logging fully functional! Basically all it does is write out the current timestamp with the two temperature readings. I also added two leds to show status, green when it writes to the SD card successfully, red otherwise.

An example written to the card is:

20100422221116 72 72

Its YYYYMMDDHHMMSS temp0 temp1

I'll use temp0 as the 'external' temperature (i.e. probe outside the container). temp1 will be inside the container.

Now I need to shrink this huge contraption into the arduino nano and solder it together into a semi-permanent contraption

Temperature Logging

I finally worked on the temperature logging system for the balloon last night. I was able to get it almost complete. Right now it is correctly recording the time and temperature (from two probes). I was able to write a test message to the SD card in the same arduino sketch as well. My next step is to write the data to the SD card instead of the serial out. Its a little tricky as I'm running into variable cast type issues. - my C programming kung-fu is not strong.

After I get the correct data writing to the SD card the next step is to switch to the ardino nano and solder everything into a small package. I also need to make a usb mini connector to leech power off of the camera's power connector.

I can haz data?

I finally managed to get my arduino to log data to a SD card. I've also previously read the value from a real time clock (RTC) module, and a temperature transistor. Now all I have to do is get all 3 working at the same time and I can log to a SD card the time and 2 temperature readings. The plan is to have a temperature reading in the capsule and outside it. I can take the time it was logged and match it up to the GPS data sent via aprs to tell what the temperature was at a specific altitude.

I also have a pressure sensor, but I have not yet tried to get that working with the arduino. Nobody has used this sensor with an arduino that I can find, so I'll have to figure out how to interface with it myself. If I can't get it working I'm fairly confident I can at least get temperature data.

My plan is to take the data from the SD card combined with the GPS data and edit the video to make said data appear like captions on the bottom of the video. That way as you watch the video it will display the GPS position, altitude, and 2 temperatures at the bottom of the screen.

Camera Ready to Go

Total weight of the camera with its battery pack and power regulator is 314g.

Mark is going to figure out a way to mount the odd shaped camera in the container, cut the container down to size and weigh everything else.

I need to test the aprs beacon with my laptop and new car gps to make sure everything is kosher. My car gps should be able to track the balloon while its moving and update the directions to it, which will be nice while driving.

I was also thinking of coming up with a check-list for launch so we don't miss any steps.