I pulled the trigger on this single use stopwatch today (prototype testing). Today happens to also be John Glenn’s 93rd birthday.
Glenn was the first American to orbit earth (1962). On his mission he hacked a stopwatch to fit over his spacesuit on his wrist. That was the only piece of tech he wore other than the suit itself. #timefromlaunch
Here’s a small test of the thermal energy harvesting circuit. It needs a few degrees of temperature difference.
Here’s the first board design. An atmega2560 connected to a 8 digit 7-segment e-ink display, powered by a coin cell battery.
The idea is to keep the battery separated from the pad with a piece of plastic that sticks out the side of the device. When that pin is pulled the battery connects and the circuit powers up. Once it’s powered up, the 7-segment updates every second to show the current hours, minutes and seconds from launch. Since there are only 8 digits, the display will continue to shift to only show the most significant digits as time increases. So eventually, the display will only show days and will refresh once a day. The max number of days the device will count in this scenario is approximately 273785 years (99999999 days). The battery would die much sooner than that.
To stop the counter, the device needs to be snapped in half. There are perforations between the display and the main chip. If and when the board is broken in half, all 50 pins connecting the display to the chip are severed and are no longer updated. Since it’s an e-ink display, it will continue to show the time it stopped counting without any power.
It’s a long time since I received my Pen Type-A via Kickstarter. That was a thoroughly interesting experience to watch the trials of the manufacture process. I remain very impressed with CW&T’s frankness and tenacity to get the pen done with awesome quality.
Having had the pen for a long time I struggled to use it … Just wasn’t working for me then recently I grabbed a few 0.5mm Hi Tec-C refills and it all started to feel right. The 0.3mm refills just weren’t right for me.
Anyways … A doodle attached … another to follow.