Rotary Wall Plug from Scrap

Rotary tools such as a Dremel are useful to have around for all sorts of tasks in a workshop, including cutting, polishing, and grinding. [Konstantin] sent us in his home made wall mount rotary tool based off of parts from a blender and an old bench top jigsaw. Unlike a Dremel where the motor is in the hand held part of the tool, this setup hides the blender motor (which provides the power) behind a wall panel, and is controlled via the blender’s speed settings buttons. We could see this configuration allowing for more delicate work due to the reduction of weight in hand, as well as the added bonus of a near impossibility of losing this tool. Overall an excellent re-purposing of leftover parts, be sure to check out [Konstantin]‘s blog for more build info and photos.

DIY Clapper

[Patrick's] latest Instructable walks us though making a clap clap on / clap clap off type of switching circuit, similar in use to that sometimes popular commercial product seen on TV. He does this by using a standard electret microphone, half of an LM324 op amp, a voltage comparator and a PIC micro controller.

The operation of the device is as simple as its wiring, the microphone picks up sound and produces a signal, that signal is stripped of its DC component and fed into the op amp, after 2 stages of amplification the signal passes though a voltage comparator, and if the sound was loud enough a timer is triggered on the pic. Two claps within the specified amount of time, the micro then switches on a relay which can toggle your outside appliance (keeping the load in mind).

On the last page [Patrick] also gives a rough outline of how to make a single clap on / off variant using a 555 timer and some flip flops. Join us for a quick video after the break, and be sure to check this one out.

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More 555 Projects to Enjoy

We love all of the projects that are coming out for the 555 design contest, so we thought we would share a couple more that have caught our collective eye.  Have a 555 project of your own? Be sure to share it with us, and keep an eye out for the contest submission dates. Read on for a few of our project picks.

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Electronic Watering Can

When [Deddies lab] was looking to keep their (rather large) Ficus Lyrata appropriately watered, they followed their motto, stuck a micro controller on it and whipped up an Electronic Watering Can .

The whole thing starts off with power that is switched on once a day for 15 minutes by a traditional mechanical lamp timer, and that is connected to a atmega8 micro controller running @ 1MHz which increments a counter by one. When that counter hits 7 the mega switches on a pump, watering the plant with roughly half a liter of water per week out of a bucket reservoir , which according to the article’s calculations should last about 4 months.

In order to assure that the pump does not run out of water a rubber duck was attached to a string, the other end is attached to a micro switch, and when the water gets too low the string is pulled, switching one of the micro controller’s pins low.

While we agree that it could use a low water indicator, that is trivial to add, and over all the project represents a great hack done on a Sunday using parts and materials already on hand. Join us after the break for a quick video too!

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Simple RFID access system clone

rfidbboards

A few months back, [John] was reading an article about a simple RFID security system kit, and decided he would like to build one himself.  While many of the system’s details, including full schematics were provided, he was dismayed to find that the source code for the project was not published as it was held under copyright by the manufacturer.  Believing that open source is better, he modified the original design, replacing their PIC controller with an ATmega328 armed with an Arduino bootloader.

His system replicates all of the original kit’s functionality, while offering plenty of opportunity for modification beyond the initial design.  The article contains a complete parts list, wiring schematic, and the Arduino code required to get things up and running.  He even has a video of his clone at work, demonstrating the acceptance and rejection of RFID tags as well as the system’s learning mode.