Category Archives: Uncategorized

Hacks and Mods: USB Keyboard Made from Old Typewriter

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Looking for a unique gift? Here’s an antique typewriter which has been modified to function as a USB Keyboard for PC, Mac, or even iPad. That’s very cool, isn’t it? In the world of obsolescence, this USB typewriter is a groundbreaking innovation. It does not change the outward appearance of… Read more »

Relay Toggle Switch

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I designed this relay circuit to function as a DPDT toggle which is controlled by a momentary switch. I strive to keep my circuits simple with little or no integration (555’s, transistors, etc). The circuit is shown active or “on” mode. Half of RL1 and RL2 manipulate the switching and… Read more »

Garage Door Closing Circuit Just using Relays

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Because I’m old school, I wanted to build a Garage Door Closing circuit without relying on integrated configurations (555 timer etc) to keep it simplistic. The circuit closes the garage door after two minutes with C3 and four minutes with the addition of C2. The timer relay is surprisingly accurate… Read more »

PWM Modulator

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If you ever thought of experimenting with pulse-width modulation, this circuit should get you started nicely. We’ve kept simplicity in mind and used a dual 555 timer, making the circuit a piece of cake. We have even designed a small PCB for this, so building it shouldn’t be a problem… Read more »

Converting a DCM Motor

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We recently bought a train set made by a renowned company and just couldn’t resist looking inside the locomotive. Although it did have an electronic decoder, the DCM motor was already available 35 (!) years ago. It is most likely that this motor is used due to financial constraints, because… Read more »

Clap Switch Diagram

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Here’s a clap switch free from false triggering. To turn on/off any appliance, you just have to clap twice. The circuit changes its output state only when you clap twice within the set time period. Here, you’ve to clap within 3 seconds. The clap sound sensed by condenser microphone is… Read more »

123 Game – All MCU-free

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This electronic game pits a human player against the ‘machine’. The opponents use a common ‘game token’ and take turns moving along a path by one, two or three steps, and the winner is the first one to reach the goal exactly. Incredibly enough, this simple version of the ‘123’… Read more »