Friday, December 20, 2013

The Oscilliscope Watch - an update

I'm looking forward to getting the beta hardware of the Oscilloscope Watch which I've funded on Kickstarter. Here is a recent project update from the developer.

Project Update #9: Beta PCB assemblies on order
Posted by Gabriel Anzzian

Hello Backers!

Sorry for the delay, I've been pretty busy these last few weeks. Here is my monthly report.

I have done some minor changes to the schematics:
  • Reduced noise by connecting the 5V step-up switching regulator to the battery, instead of the VDD rail. It will also be a little more efficient, since the regulator is converting 5V from 3.7V, instead of 3V.
  • Minor tweaks to reduce current consumption: increased value of some resistors, changed the diodes to low leakage versions.
  • Removed the 15pF input capacitors, which aren't really needed for the bandwidth that the OW works with. I also needed the space to add mounting holes.
  • Added load capacitors to the 32.768kHz crystal.

I had a hard time making space to add the mounting holes while still keeping current packages of the components. I only changed the LEDs from 0805 to 0603. Now there are two nice mounting holes on opposite corners, which will be great for fixing the PCB to the enclosure. I also moved the slide switches towards the center to solve a problem with the enclosure as discussed on update #4.

 Oscilloscope Watch PCB rev 1.4 

PCB Assemblies

I originally thought of assembling the Beta units myself, this was when I thought I would have only 10 Beta testers. Now with 28 Beta tester units, and a few spares, it makes more sense to have these assembled at the factory. I am ordering the assemblies and they should be ready in about 6 weeks.
I am going with a 380mAh battery, it measures 40mm x 30mm x 4mm, the dimensions of the watch are not changing. I have already received enough samples of these for the Beta tester units. The battery life should not change much from the initial estimates.


I bought a translucent filament to use on my 3D printer to make a backlight diffuser, it didn't work. The problem is not because of the translucent diffuser, which I already knew that it was not going to be too good. The problem is the LCD it self, it does not let much light go thru.
 Backlight experiment 

So I started to research what I needed. I contacted Sharp and they referred me to a company that does "front lights". I have just began talks with them, we are signing NDAs.
The Beta units will still have the backlight diffuser, but this is to make everything fit together, rather than functionality.

Not many changes to the enclosure. I tweaked the sliders to fix the collision problem, I moved the charging LED location to right above the USB connector, and made the LED see-thru holes circular. I also added the screw bosses on the TOP part.

I haven't done much to the code, only some minor tweaks to reduce current consumption during the watch mode. Once I get the Beta units, I will set up a repository, initially for Beta Testers. I am looking forward to working with the Beta Testers!

A lot of work to still to be done, but it sure is fun!

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