handmade digital altimeter watch

[valerak 0]

Hi guys.

I have made skydiving altimeter based on Ti Chronos watch. http://www.ti.com/corp/docs/landing/mcu/index.htm?DCMP=MSP430&HQS=Tools+OT+ez430
It`s watch with negative LCD display and open source code. You can order EzChronos watch at the Ti shop for $50 with free shipping here: http://www.ti.com/tool/ez430-chronos?DCMP=Chronos&HQS=Other%252bOT%252bchronos#buy My firware based on original EzChronos.

See photo:
http://processors.wiki.ti.com/images/thumb/0/03/Skydiving_altimeter_pic.jpg/400px-Skydiving_altimeter_pic.jpg

I have implemented some features special for skydiving:
Automatic zero level set.
Blank second line.
Different simple pressure to altitude function.
Altimeter timeout (12 hours) for battery saving.
Direct altitude render without filtering.

You can find the souce code and compiled firwares foe all 3 version of watch at the wiki page: http://processors.wiki.ti.com/index.php/Skydiving_Altimeter.

I have made some jumps with it and altimeter works pefect. May be it will be interesting for skydivers and we continue the project together.

[shropshire 0]

I love my Chronos too

(.)Y(.)
Chivalry is not dead; it only sleeps for want of work to do. - Jerome K Jerome

[hackish 8]

Nice work! I took a quick look at the source and it's nice to see something well written, formatted and documented. Does the watch have any sort of NV storage associated with it? If so maybe you could also implement jump logging as well.

-Michael

[valerak 0]

Thank you, Michael.

EzChronos totally have 32kb Flash and 4kb ram memory.. It`s possible to use about 7kb to store any data you want...

My primary task was to make nice altimeter.. And now i want to improve it. Other features not so preffered.

PS: Microcontrollers programming is my hobby and it`s first time, when i try it...

[koppel 3]

Hey

I use a Suunto Observer. I find it a good alti except that if a button gets nudged then it is no longer an alti but a barometer! or a compass! not really very helpful

does your system allow for it to be locked onto alti function.

also can it be a data logger.

I am very interested in getting one if it can do those things. :)

cheers for the good work

I like my canopy...


...it lets me down.

[hackish 8]

Quote

Thank you, Michael.

EzChronos totally have 32kb Flash and 4kb ram memory.. It`s possible to use about 7kb to store any data you want...

My primary task was to make nice altimeter.. And now i want to improve it. Other features not so preffered.

PS: Microcontrollers programming is my hobby and it`s first time, when i try it...

I was hoping you'd find some serial eeprom on it where you could save a log of the jumps. As soon as I have more hours of spare time I might order one of those watches and contribute a bit. As a side project I was thinking of hacking the firmware in my L&B so it could do some extra special things :P

-Michael

[IanHarrop 37]

For the un-informed....

What does it take to load the software on to one of these watches?

"Where troubles melt like lemon drops, away above the chimney tops, that's where you'll find me" Dorothy

[Coreefdiver 0]

Quote

For the un-informed....

What does it take to load the software on to one of these watches?

this thread is of interest to me
I have a eZ430 and played with it for about 5 min.
set it aside till I could gather all the things I was looking to do for another, yet related project....time to dust the box off.

the watch comes with everything you need to program it. (adapters and software)

DS#727, DB Cooper #41, POPS #11065, SCR #13183, FA #2125, SCS #8306, HALO #309 SRA #5930

[valerak 0]

2IanHarrop
When you buy ExChronos for $50 with freeshipping on Ti eStrore site, you will receive:
1) Watch with battery
2) Screwdriver
3) radio trasmitter for PC (USB)
4) debugger (USB)
5) software cd

If you have compiled working firmware (see links in the first post), flashing watch is very simple... You do not need to disassemble it.

Folow this steps:
1) Install EzChronos from cd or (it`s beter and newer) from Ti site. As i remember, driver for RF board installs automaticaly. If not, when prompted, terget to CD folder with drivers.
2) Insert RF board to PC
3) Launch EzChronos Control Center, go to Wireless Update tab
4) On your watch press # button to see rFbSl, press right bottom button twice to start update
5) In Chronos CC browse for firmware file for your version of watch (915, 864 or 433 MHz). Press Update Chronos watch.

If everything is ok you will see progress indicator and you watch will be updated via radio. After that, watch will restarts and that`s all.

If somthing goes wrong, you need to use debugger board to repair it.

[valerak 0]

Also i whant to write about difference betwen my EzChronos watch and other watches, that you can bay at the market.

I have Sunto S-Lander and made 30 jumps with it. I think, other sunto uses the same algorithm (Core, Oserver and other with presssure sensor).

First of all you know that all of them does not situable for skydiving. Every company (Sunto, Casio..) writes it in the users manual. It`s not only words (safety, lability)... The are some technical things, that makes watches to be a not good altimeter...

Some watches better than other... Sunto is good watch and the best, what you can use for skydiving.. But not ideal... Let`s chek main problems of watches for skydiving:

1) POWER. Hah, why power? All watches have small battery and need to work 1-2 years on it. That is why all of them uses many power-saving algorithms. Minimum display (and pressure measurment) speed must be 1 Hz for skydiving. Many watches with pressure sensor you can`t use for skydiving becaus they are very slowly. Sunto, when you start falling down, turns off power saving and set update speed to 1 second. But....

2) They all have an algorithm for filtering altitude value. It filters big value splashes because it think that you are hiking in mountains... Simple examle (first row - measured value, second - display altitude):

0 5 0 50 100 ... 4000 4000 4000 3900
0 0 0 20 50 ... 3900 3950 4000 3980...

I compared viso altimeter with Sunto S-Lander and delay was significant.. Difference was 50-200 meters..

3) Locking buttons.. I have jump one time and see 12:50 :)))) Time to open my chute 12:51 :))) It`s good, that i have audible altimeter :)

4) Other information on display... You can`t turn of other data like date or second.. It`s divert attention.

I think enough.

Now about my firmware.

1) Update speed 1 Hz. Everytime. To save battery there is 14 hourse timeout.
2) Meaured altitude displays directly. There is no filtering when we are higher than 50 meters.
3) You can turn of other information (date, second...) and make visible only altitude
4) Locking buttons also works :)))


May be something need improovement...

First - feet display only to 9999 (only 4 digits in the top line). i don`t need feets but may be someone needs it.

Second... Because of very simple automatic zero ground level set algorithm you need to climb up faster than 1 meter per second first 50 meters. All planes on my dropezone have climbing speed 3-6 m/s. May be if you use Deltaplane or othes small (or old) planes it will not work.

Peace!

[roostnureye 2]

i just got a suunto core anniversary edition and am very happy with it, you can actually get some good info at chutingstar, they put the suuntos in a pressure chamber with other altis and test them. they claim at 20k there is minnimul differences between them, i like mine for climbing A's, i can zero it on the ground, lock the function and not worry about it. it even has a function to enter the "climb" height and it will tell you how long it will take you to get to the top in real time. refreshes every second too. just dont set the alti/barometer profile to automatic and you will be fine. although my alti is not used while in freefall.

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