Dave Prochnow Never burn your mouth on a hot drink again No matter your poison -- coffee, tea, hot chocolate, sake -- take a gulp too soon out of the pot and chances are good that you'll burn your mouth. But build this Smart Coaster and you'll ...
16-12-2008
I'm just toying around with this idea at the moment. If I start using photo exposure PCB type production, I'm probably going to need a light box. I have tried using spray on photo-sensitive resist and exposure to the sun. It was a complete failure. ...
15-12-2008
Using a CMOS 555 timer and a single NPN transistor, you can drive as many as seven LEDs using a minimal amount of voltage and power from a single NiMH (nickel-metal-hydride) AA cell. The circuit works by creating much higher-voltage pulses than the ...
03-12-2008
By Rahul Srivastava, VU3WJM TNC and Modems ruled the world of digital communications until recently. With the advent of high speed computing and digital signal processing (DSP) all this has changed. If you own a home computer (PC) with a sound ...
02-12-2008
My goal is to build a kind of a mobile tracker. There are many different use cases you can think of but one of the obvious is a device, that is able to report where it is. This device can be put in your car and it could trigger an alarm, if the car ...
01-12-2008
n this article, we point out some important facts in designing RF application PCB boards. Of course there are many other facts that are not listed below but for the beginners these may be enough for now. First of all, separate the analog , RF and ...
27-11-2008
his is truly a simple digital thermo meter, a beginner’s project, but having sufficient accuracy. The brain of this circuit is PIC16F877A ; a Microcontroller from Microchip and it is easily available now. It has an inbuilt 10 bit Analog to ...
20-11-2008
Introduction This circuit stores a single morse code message as bits in an EPROM chip, the message is sent to a relay which can key a CW transmitter. The keyer can output either a one-shot message such as CQ DX DE CALLSIGN, or a continuous message. ...
16-11-2008
Here is a new version of the classic color organ, where different color lights are triggered by different frequencies of sound, resulting in a display that flashes along to music. In this case the newer type high intensity LEDs (3000 - 5000mcd) ...
13-11-2008
The Curious C-Beeper uses the two-transistor flasher in conjunction with a darlington transistor to make a most unusual capacitance beeper probe. When a capacitor is touched to the probe, the probe beeps at a frequency that varies with capacitance. ...
12-11-2008
Description: In this 2-7 V power supply circuit, for our purpose, we chose IC 723 instead of a three pin voltage regulator for-why we find it protean and more advantageous in technical details. Notes: Heatsinks of Tr2 and Tr3 transistors must be ...
10-11-2008
06-11-2008
What could be better than having a little instrument with you all the time, hidden in your hat? Insiders Tip: Don't take this to the airport. The inspiration for this project came while on the long road trip to Austin last weekend, and I finally ...
06-11-2008
Inputting multiple bits of information using a single entry pin of a microcontroller without the complexity of UARTs can prove useful. Such a scheme could allow scanning of a keyboard, mode switches, or any relatively slowly changing digital data. ...
05-11-2008
Description: This circuit will power a 6 inch 4 Watt fluorescent tube off a 12 Volt supply, consuming 300 mA. It may also be powered by a suitably rated universal AC/DC adapter. Advantages of the design are: good light, low power consumption, and ...
05-11-2008
This rain detector will give you a heads-up the instant it starts to rain, hopefully giving you time to close windows and bring in possessions. The battery-powered circuit draws virtually no current when the sensor is dry and the current ...
05-11-2008
Key-Glove Recipe Ingredients 21 Dritz nickel snap on 3/8 snaps from local fabric store ($ 5) 1 pair of black leather gloves from Wilson Leather ($ 20) 1 CompUSA 101 Key keyboard model #MKB931 ($ 15) 1 spool wire wrap wire from Radio Shack ($3) ...
04-11-2008
Dave Clausen The problem: Grass dies without strong sunlight. The solution: Construct a grow light that doesn't consume a lot of power, doesn't block the natural sunlight, and produces natural-looking colors. Step 1: Solder up strings of red, ...
02-11-2008
This Instructable will show you how to put together some LeD Spidies for Halloween. They are simple to make and fun to hide in dark corners for guests to find. I have tried to keep this simple and to the point for the younger viewers. If you are ...
30-10-2008
Andy Collinson Description: A simple device to indicate various levels of hot water in a tank. Notes: Save fuel bills and the economy of the planet with this circuit. SW1 is a normally open press button switch which allows you to view the level of ...
29-10-2008
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