ASync-Firefly

March 11, 2011 by Noah Dunker 8 Comments

[dev_dsp] wanted to try his hand at creating a purely analog implementation of multiple synchronizing fireflies powered by a single battery and built from off-the shelf, through-hole components on inexpensive protoboard. In theory, even your local Radio Shack should still carry all of this stuff. He was obviously inspired by [alex]’s fireflies that we’ve covered in the past, but he wanted to see how far it could be taken without the use of a microprocessor.

In the end, [dev_dsp] relied on one crucial piece of digital ware, the ever-popular 555 timer IC, but he’s using analog discrete components to do the grunt work of adjusting the phase of each firefly by feeding a little extra current to the trigger capacitor whenever the flash of a nearby firefly is detected. After the jump, you’ll find schematics and a video demo of three ASync-Firefly modules in various stages of assembly playing with one another while [dev_dsp] discusses their operation.

Automated Chicken Coop Door Is Solar-powered

November 27, 2010 by Mike Szczys 12 Comments

[Fileark] has been busy with the hacks lately. This time around he’s built a solar-powered chicken coop door that opens in the morning, and closes at night. A single motor slides the door open and closed using a loop of spring-loaded string. There are limiting switches on either side of the door jamb to ensure proper positioning. The grey box seen above houses the hardware; a regulator for the solar panels perched atop the roof line, a battery from a broken UPS, and the driver board itself. An AVR chip running the Arduino bootloader monitors a phototransistor to detect sunup and sundown, driving the door motor appropriately using a pair of relays.

Check out the demonstration and hardware overview after the break. [Fileark] was inspired to build his after seeing the alarm-clock coop door. We don’t know if he got a chance to look at the vertical coop door, but we think his less mechanically-complicated solution is just as elegant.

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Line Following Tank Without A Microcontroller

September 17, 2010 by Mike Szczys 23 Comments

This line following tank uses analog circuitry to sense where a dark line is and adjust its course. Despite the opening paragraph on the schematic page (which looks to be leftover from a past project writeup) this circuit relies on a set of transistors for motor control. [Chris] does a great job of explaining the setup in detail; it boils down to a phototransistor detecting reflected light and flipping which motor is running based on what is detected. A couple of potentiometers are included to tune up the accuracy of the circuit. There’s a short clip of the treaded-terror making a loop around the track after the break.

This is another great way to try your hand at analog circuitry. Once you’ve built the body (tank or otherwise) and line tracking circuit it can be repurposed by swapping out the brains for your next project.

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64 Synchronizing Fireflies

June 25, 2009 by Zach Banks 14 Comments

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[Alex] of tinkerlog created a set of 64 RGB fireflies that synchronize to blink all at once. We covered the kit earlier, but he has assembled a set of 64. Each firefly is independently controlled by an ATtiny13 that reads a phototransistor and lights up an RGB LED. The fireflies are programmed to blink a certain rate, but blink faster if they detect other blinks. After a few cycles, the fireflies begin to blink in unison. When the fireflies are arranged in different configurations, different patterns emerge. He is selling kits and has instructions for building your own. Videos of the fireflies after the jump.

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Phototransistor Multitouch With A Twist

June 4, 2009 by Caleb Kraft 9 Comments

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[Alex] sent us this project he’s working on where he’s building a phototransistor based multitouch input system. Though many people have built systems with phototransistors, most of them are quite large and very sensitive light and dark variances. [Alex] has done some fancy background subtraction through software. He believes his is the first to do this. As you can see in the video after the break, it seems impervious to the lamp he is moving around, and still fairly sensitive to his hand. We’re curious to see where he takes this one.

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