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Archive for March, 2021

Breadboard

Posted by doc on March 22, 2021

The same circuit on breadboard. This enables me to swap components with different values to test out different configurations. For example, to make the LED blink faster.

Don’t worry, I have tidied it up later, replacing those naked copper connections with proper jumper wires.

And the four jumper wires in the photo connects to a toroid elsewhere.

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Circuit Board

Posted by doc on March 22, 2021

I drew this circuit using Fritzing’s PCB view.

The result:

The problem with this circuit board is the gaps were too narrow. Even with a little moisture, where will be leaking current somewhere. However, with thorough cleaning (with dish washing paste) and drying (with a hot air gun), it worked without a problem. Hot components will make the LED blink faster.

So I made another one:

Still need to wash and dry to get rid of leaking current.

I have also made a templates out of 2mm acrylic sheet. This will let me make more circuit board easily.

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10-year LED Flasher

Posted by doc on March 22, 2021

I got this diagram from https://www.instructables.com/10-Year-LED-Flasher/.

There is another from https://www.hackster.io/simpletronic/10-year-led-flasher-398282 but I tried on breadboard and it didn’t seem to work.

The obvious difference is the lack of a diode 1N5819 in the later.

This circuit is supposed to light an LED bulb for 1/1000th of a second (1mS), every second, for 10 years, using an AA battery.

If you switch the AA battery with a D type battery, which carries 10 times the charge, it may blink up to 100 years, provided that the battery doesn’t deteriorate sooner.

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