https://wiki.tjhowse.com/ 2026-04-21T12:18:52+00:00 https://wiki.tjhowse.com/ https://wiki.tjhowse.com/_media/wiki:logo.png text/html 2022-02-17T02:24:23+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.tjhowse.com/projects:blinker:work_logs:1_beginnings The Beginnings The Plan I want it to be very reliable, which means as few points of failure as possible. The initial versions will have a very simple, inefficient circuit. I plan to use supercapacitors for the storage, for their long life. Ideally the solar panel would produce a voltage no higher than the rated voltage of the supercaps. text/html 2022-02-17T02:24:14+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.tjhowse.com/projects:blinker:work_logs:2_window The window The Plan My initial plan for the window is: * Cut a few circles out of some float glass, * Clean them thoroughly with IPA and HCL, * Build a stack of them to the desired thickness, * Fire in kiln: * Slow ramp to 775°C, * text/html 2022-02-27T05:40:48+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.tjhowse.com/projects:blinker:work_logs:3_electronics The Electronics The Plan I want this device to continue to operate for many many years. To achieve this I want to use as few components as possible, so there are few things to go wrong. PCB design is definitely my weakest area of expertise. I'd like to credit all the folk who helped with this project from text/html 2022-02-17T02:24:35+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.tjhowse.com/projects:blinker:work_logs:4_window_2 Window 2 The Plan I will make another window, using the lessons learned from making the first one. Hopefully this one will be good enough to incorporate into my first blinker device. This time I will employ a new technique for creating neater glass circles, and rinse the glass with deionised water after the acid bath. I will also attempt to smooth the kiln/bat wash to get a better bottom surface. text/html 2022-03-07T04:48:28+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.tjhowse.com/projects:blinker:work_logs:5_destructive_testing Destructive Testing The Plan I will evaluate the relative mechanical strengths of the two windows I've created so far by dropping a 28.15g steel ball onto them from increasing heights and studying the results. After each drop I will inspect the window for damage. If I find any, I will circle it with a permanent marker to ensure I don't confuse earlier damage with later drops. text/html 2022-03-07T04:47:52+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.tjhowse.com/projects:blinker:work_logs:6_power_consumption_testing Power consumption testing The Plan I want to measure the voltage over time as the device discharges so I can calculate how much power each component uses. I will run the following tests: * JP1 open, disconnecting the LED and microcontroller from the supercaps, text/html 2022-03-03T07:17:53+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.tjhowse.com/projects:blinker:work_logs:7_code Code The Plan The message and the code to display the message on the LED must all live within the same 1024 bytes. I must strike a balance between efficient storage of the message, and efficient code to unpack and display that message. Cleverer code would let me crunch the message into less storage, but the code itself would probably take up more space to store the cleverness. text/html 2022-04-17T23:45:12+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.tjhowse.com/projects:blinker:work_logs:8_solar_cells Solar Cells The Plan I want to build a 3v solar array out of 0.5v solar cells. This array should collect as much light as possible coming through the glass window. This means it should be a circular array, about 60-70mm in diameter. I will buy some monocrystalline solar cells and work out how to cut+join them to form the shape I need. text/html 2022-04-18T05:02:36+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.tjhowse.com/projects:blinker:work_logs:9_resin_casting Casting electronics in resin The Plan I wanted to run a medium-duration test of the electrically-complete blinker before going through all the trouble and expense of encasing it in aluminium and glass. I decided to cast the electronics in transparent resin. This would be reasonably mechanically and chemically robust, but it would degrade in sunlight over a few years, turning yellow and crumbling. However this would be a reasonable test for any drastic short-term problems with the electronics. text/html 2023-04-12T11:40:33+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.tjhowse.com/projects:blinker:work_logs:10_new_design New design The Plan Given the majority of the power consumption of a blinker is leakage current across the voltage-limiting zener, I thought I would try reducing the number of cells to bring the maximum voltage down under the voltage limit for the supercaps, and leave out the zener.