Wanna Make A Garage Door Open Alarm This is a continuation of my previous blog. I could use two 555 timer chips in the astable mode to generate a European type siren with the high-low ‘warble’ tones, but I decided I would do it with a couple transistors. Actually I coul+d use a single 556
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I assembled the circuit to see if I could come up with an alarm. Wanna make an Open Garage Door Indicator Alarm The circuit uses two transistors in a circuit that needs only a single timing capacitor and timing resistor to determine the frequency. It’s somewhat similar to the flasher circuits I’ve been working on,
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In 2009 we decommissioned the old PBX system after replacing it with a Cisco VOIP phone system. Most of our campuses just got rid of the equipment lock, stock and barrel, but the whole room full remained at my campus. Over the years, I retrieved a few of the boards, each one about 16 inches
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This is from the 1980s, it’s all red LED segments or dots. I tried to find an angle where the ceiling light would not show, but because it’s a bubble lens, just about any angle had that white reflection. The specifications are available on the ‘net. The box outlined in red is one of the
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Chocolate? Paul has talked about using hot glue to hold the circuit to a ‘chocolate block’, but I’m not sure if that’s the same as the European style connectors we can get from Radio Shack. I did manage to find dark colored versions of them in a Google search, but the only color I’ve ever
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I wrote a short blog about the Cree LED lights recently. Last week I bought two Cree 450 Lm (40W equivalent) LED lights from Home Depot for ten bucks apiece. The UPC label number is 13959 01932. I installed one of them in a task light I have over my laptop, which gets heavy usage,
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