Saturday, January 31, 2009


Here is a quick screen shot of how my Cubesat looks on an APRS map. Like the icon?

Monday, January 26, 2009

Cubesat awarded honorable mention!

Bryan's Cubesat project was awarded an honorable mention at the Hanalani Science Fair. All the first place finishers were recommended for entry to the District Science Fair, but the judges specifically recommended Bryan's project be included as well (the only non-1st place finisher going!).

We are also pleased that the 1st place finisher in Bryan's age group is his good friend Scott. He won 1st place for a behavioral research project about the effects of mobile phone use while driving. Bryan's brother Bradley also submitted a beautiful science fair board this year about rat intelligence (his first science fair ever!)

The District Science Fair begins on February 9th.

Congratulations Bryan!

Thursday, January 22, 2009

Mission Complete!

It is done!  It's up to the Hanalani judges now to decide who goes on to the District Science Fair.  Bryan says the competition is tough this year.  Bryan has learned so much that this project is already a success.  Enjoy the photos!



Beginning the display board



Last Days of Construction








Wednesday, January 21, 2009


The satellite is now completed!  I completed the power board we eventually  fit everything in between the relays and got all the pins to stay in place.  We would put the power board in, realize something doesn't work, disassemble it all, fix whatever doesn't work, and put everything back into the case.  We did this about three times.

Its a really tight fit.  Everything has to be squeezed in.  After I put them in I have to use needle-nosed pliers to squeeze between the boards and plug in the leads.

I need to build the board and construct the full program even though I will never be technically able to run it with this microprocessor.  The best I can do is to tell the emulator on the PC that I have the needed memory then test it to see if it would have run.

1st photos after construction.

1:30 A.M.

Its 1:30 am.  I just finished making the actual satellite.   The programing still needs some work.  Tomorrow I have to start and finish my board.   More details to follow.

Friday, January 16, 2009

Forward Progress in Pictures





Today I wrote the PBASIC program to remotely operate my satellite.  It was my first coding project from scratch.  It took me about a hour to get the basic shell running.  Then later on we polished and commented the code.  We ran into a problem.  The code is too big because our stamp's memory is only two kilobytes.  We got rid some of the unnecessary parts and shoehorned it into the EEPROM.  

Thursday, January 15, 2009

Four Day Weekend

Today I replaced the diode that my dad burned out.  It was pretty easy all I had to do was desolder the old one, find a new one from my parts drawer and put it in with the right polarity.

We also got a relay circuit to work.  We powered the APRS on and off using a simple relay circuit.

The combined voltage of all the solar panels if 3 were facing the sun was 1.5 volts, but 4 amps.  The battery needs 12 volts to charge.  If I used a transformer I can basically convert those amps into volts.  We used a formula to calculate how many wind on each side of the transformer we need.  It turns out I need 12 winds on one side and one on the other.  If I do this it will charge completely but will take about 12 hours to charge.

Because of hurricane like conditions tomorrow and a holiday on Monday I have a four-day weekend to work on the project.  Tomorrow I am going to be working on the program to turn all the systems on and off by command. 

Tuesday, January 13, 2009


We had a little scare tonight.  Bryan was busy all night memorizing the Gettysburgh Address for a history test tomorrow, so I was fiddling with the power bus board trying to get it in my head how the STAMP microcontroller was going to control relays to power the different components.  

Well, in the process of prototyping the connection, I got two wires crossed and when I powered up the APRS board, instead of activity lights I got tiny "Psspt" and an ever so faint wisp if smoke!  That's not good.  As my engineer friend always says about electronics, "The trick is always keeping the magic smoke inside!"

I de-powered immediately and saw my mistake.  After correcting it, I checked the operation of the APRS board and it failed.  It would no longer power up.  Uh oh.

I went and fessed up to Bryan and wrote the owner of Byonics for advice.  Fortunately I got an encouraging response:

"There is a small glass diode mounted near the tab where the RF metal can sits. Just use a pair of nippers and cut it off. This is the reverse polarity protection diode. "
Basically the circuit has a small diode to protect the more expensive parts in the event of a backwards connection.  It dutifully sacrificed itself to save our board!  We will replace that diode before applying power again, and it will give Bryan and I a chance to discuss how the protection circuit worked.

Whew, that was close.  I think everything gets a diode now!