VMM

Another 430 Watch

25 posts in this topic

Hello.  I figured I would share a project I've been working on since I borrowed a lot of code from this forum.  It's a small watch using a g2553 and the same OLED display as "The Terminal".  Thanks bluehash for the breakout, RobG and gwdeveloper for code, and others.  ;)

watch_1-300x272.jpg

CorB, username, spirilis and 14 others like this

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Schematic is here:

http://voodoomanmiracle.com/wp/?p=59

I will try to add more info there.

 

It's basically the same as your OLED booster pack.  This made it really easy to test code on the LP + Terminal without changing anything for the watch.  There is also a place for a current sense resistor to monitor current while running off the battery.

 

I want to add an accelerometer in the next version.  I'm currently looking for a good part for that, and open to suggestions.  I want to use that to replace some button functions.  For example, tapping twice on the screen to show time, or twisting your wrist.

 

I'll try to share some boards with you guys on the next round.  Current version is a little bodged.  I put some vias too close to the flex ribbon pads, etc.

bluehash likes this

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Need the Z axis to make the tap thing work.  Could probably find a use for the others, but not necessary.  I want it to be able to trigger an interrupt to wake the micro.  Don't want to keep polling it.  Programmable threshold on that would be nice.  And low power is big priority.

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I got the display from gabotronics.  I also got some blue ones from a shady chinese company, but they don't seem to work for this.  There really isn't much of a case.  I filled between the display and pcb with epoxy.  Glued on the tips of some servo horns for watch band lugs.  Made a back plate from some sculpey.  It's actually holding up pretty well, but I'll probably get something better done on a rapid prototype machine at some point.

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I got the display from gabotronics.  I also got some blue ones from a shady chinese company, but they don't seem to work for this.  There really isn't much of a case.  I filled between the display and pcb with epoxy.  Glued on the tips of some servo horns for watch band lugs.  Made a back plate from some sculpey.  It's actually holding up pretty well, but I'll probably get something better done on a rapid prototype machine at some point.

Lars' watch might provide you with some inspiration.

2011-06-30 13.40.25.jpg

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Yeah.  Something like that.  Case design might actually be kinda tough.  The buttons are the hard part.  I'd also like to keep it as small as possible.  Will need to brush up on my 3d modeling.

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low power accelerometers are very expensive.  You could rig-up a piezo shock detector, though, for the sort of feature you're chasing.

You're right about price.  I don't really mind, though, as I don't plan to mass produce or anything.

I think the piezo would require a lot more design considerations.  It would also be larger.

With the accelerometer, all the fine tuning can be done in software.

 

I also had the idea to use it to log sleep patterns.  Graphs could be shown right on the display in the morning.  

 

edit:  I may be wrong about the piezo.  Do you think the flexible film type could be adhered to the back of the display and function as described.  It wont flex much behind the layers of glass.

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How long where you driving the watch with the display on?  and what kind of mA are you drawing awake vs in sleep?

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You're right about price.  I don't really mind, though, as I don't plan to mass produce or anything.

I think the piezo would require a lot more design considerations.  It would also be larger.

With the accelerometer, all the fine tuning can be done in software.

Fair enough.  The lowest power MEMS accelerometer I've seen is from Analog Devices.  I forget the part number, but if you go onto the analog.com website, you can search and find the one with the lowest current.  It has an automated low-duty mode that will drain 1.8 uA, IIRC.  To get lower than that, you need to rig-up a piezo.  Considering that MSP430 has comparator, timer, and ADC in the peripherals, the piezo solution would be largely software-bound as well.

roadrunner84 and bluehash like this

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Nice!  Which accelerometer did you choose?  I've been experimenting with some of the really small chips from ST.  They are getting down to <$1 now.

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i went with the LIS3DH.  it has some neat features i wanted to play with.  a lot of these accelerometers are mostly pin compatible though, so i may be able to use something else if i need to.  i also decided to go with a FR5738 this time.

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yeah, that may have been a better choice.  i don't really need the adcs on the 3DH or the higher resolution.  i may try to change it, but i had a hell of a time routing the traces for that.  ;)

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Well, it's up and running.  All the hardware seems to check out.  Display and accelerometer are playing nice on a shared spi bus.  The FR5738 RTC is keeping time.  LIS3DH initialized and generating interrupts properly.  Lots of programming to do now for the interface, calibrations, etc.

ftw.jpg

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@vvm

 

i have managed to write some code into OLED display but now i am looking for a piece of code to write the timer on the OLED just like a clock timer you have on this project.

could you please share your code with me ?

is it CCS code ?

 

regards,

 

miha

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