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Smartwatch: Automata :: First Assembly
11/20/2023 at 22:19 • 0 commentsFirst assembly of Alpha Automata version (lol).
Solid stainless-steel body, anti-allergenic, anti-magnetic 316L (a.k.a. surgical steel).
Silicone strap.
Already see a number of problems, and some will need to be addressed way down in R5 (we are currently at R2).
Regardless, will report later with actual working version once I confirm PCB.
Cheers!
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Revision 2 of the main board is here!
11/20/2023 at 16:53 • 0 commentsExciting news, the R2 (actually that's R3 but I started counting from 0 so here we go) of the main board is here, will post pics later today (I have a full time job, you know :)
And R3 is also on the way for manufacturing, and I already started planning R4.
Cheers!
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Depth Pressure Sensor / Water Dive Depth
11/19/2023 at 23:28 • 0 commentsSensor for depth measurements:
https://www.te.com/usa-en/product-MS583730BA01-50.html
30 bar/300m, 1uA, i2c
Seems like a winner, for only $14, will see if I can get a sample to add to the watch as a dive option.
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Color LCD exploration
11/19/2023 at 16:20 • 0 commentsWhile waiting to get things manufactured, and on/off working on the alarms, I also looked into a color LCD.
At 1Hz refresh rate, and 1Ah battery, assuming no other power draw, this is a 5uA display, which corresponds to about 22 year life. I see many problems here, most notably the need for well regulated 3.2 and 5.0 V dual power source, but that's for future consideration. Not bad, and definitely worth the next iteration if anyone would like to explore a color variant.
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Micro Current Measurement Instrument Update
11/18/2023 at 18:13 • 0 commentsOrdered the PCB fully assembled, without going into details, will take up to a month to get it to my desk, this is not really a critical step of the design process, I can wait. If the tool is successful I'll open it for others to order.
I have a commercial nano-amp meter for that work but it's always cool to develop your own tools in the spirit of the fully self-contained design/development bootstrap effort.
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Micro Current Measurement Instrument
11/17/2023 at 20:06 • 0 commentsI need to measure fast transient micro-current values, and found an abandoned project on eevblog:
https://www.eevblog.com/projects/ucurrent/
Thank you, Davy Jones! https://www.siliconchip.com.au/Issue/2009/April (awesome name BTW).
Got the schematics and during a long and boring meeting I had, I filled my time with making from scratch a replica for myself, as the module seems to be out of stock and not available anywhere else. I wanted to buy it but no luck, so making it it goes.
Ended up replacing some components, due to personal taste and general availability, and will try to manufacture soon. Perhaps biggest are the large capacity coin cell battery holder, and the massing 10mO grid sensing resistor to improve the error. In fact, I do have an advanced nano-Ampere meter, however, that's way too bulky and fancy for my taste. Also, not everyone could afford such tools, therefore, I will make that available perhaps as a separate satellite project for people to use if they need something like that.
Not bad for an hour work. Sometimes long and boring meetings do have an upside.
Cheers!
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Revision 3 progress --- for technical audit
11/16/2023 at 20:11 • 0 commentsRevision 3 was submitted for technical audit and manufacturing, let's see how that goes.
It's a little bit of a routing mess due to the debugging connections, but all the important points are met.
-magnetometer/compass
-accelerometer/imu
-power-down
Stay tuned!
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Revision 3 Progress
11/16/2023 at 02:02 • 0 commentsRe-arranged the entire PCB, re-routed and added a magnetometer and accelerometer, as well as an external means of power-down, which is actually pretty clever, might I say. Again, component selection, component selection, component selection... it's the key to success. Study hard kids, and spend all your time reading data sheets, instead of watching... haha.
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Accelerometer
11/15/2023 at 17:38 • 0 commentsSome random notes.
Component selection is key to success. Not reading documentation is for quiche eaters.
Did you know you could find and SMD an accelerometer with 500nA (yes, nano-Amperes) consumption and 50 nA power-down mode? Putting things in perspective, on a 1Ah coin cell battery this equates to over 200 continuous measurement years run-time, or if you get creative you could exceed 1000 years...
Put that in your pipe and smoke it.
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Revision 3
11/14/2023 at 15:53 • 0 commentsWhile waiting on Revision 2 of the PCB, I started working on Revision 3.
In parallel I'm also adding the alarms features in the SW/firmware, going is slow as I have a full-time job, obviously.
For HW Revision 3, I will include:
1. Accelerometer --- steps, body activity, what else? Taps? Since we have no buttons, and no touch screen, the watch enthusiast could use taps and shakes to control certain functions of the watch that would allow for standalone/independent watch operations from the smartphone.
2. Magnetometer --- digital compass feature.
3. Depth sensor --- since the watch has no buttons, it could withstand extreme depths. I really wonder how salient/relevant such a feature could be though, might add it as an optional? Could that watch be used as a dive watch?
4. Altimeter --- again, I'm not really sure how relevant an altimeter would be. An altimeter goes with a GPS, and we don't have a GPS (or not yet, huh), so what gives? Might add it as an optional?
5. Heart/oxygen sensor --- this is a hard no. The body sensors are notorious power hogs and would drop the battery life down to months from years. Case in point, the lowest power blood sensor is about 100uA, which under the best circumstances, if I get really creative with the power management, would drop the life to 1 year.
6. Full power-down battery disconnect --- that's a must, but how (???), since the watch has no buttons? I have a crazy idea, but it needs to be tested because this would involve some really creative work.
7. Screen LCD light with an LED --- that's a hard no. Massive power hog. Yet, again, I have a really crazy idea, but it needs to be tested because this would involve some really creative work and perhaps some legal research.
8. Alarm piezo --- about to test the validity and power consumption.
9. Vibro alarm --- as bad as it sounds from power management standpoint, it might be an option, considering the massive advantage of having a vibro inside the watch.
10. --- ??? Anything else? GPS is a hard no, that's a massive power hog.
11. Atomic clock sync up --- probably also a hard no, unless I find an easy way to do it.
Lots of things to do.
Cheers!