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Timer kits are an ever popular item with the hobbyist. One of the main methods used is the ever-popular 555 timer IC. In this circuit we use a 555, a counter IC and a transistor switch to activate a relay either on-to-off or off-to-on (mode selected by a jumper) as soon as the counting period is over. Let us look at the kit in more detail. The circuit consists of 3 parts: an oscillator, a ripple counter and two switching transistors.

In this Countdown Relay Timer, a 555 IC, a counter IC and a transistor switch to activate a relay either ON/OFF (mode selected by a jumper) as soon as the counting period is over. The circuit consists of an oscillator, a ripple and two switching transistors. The 555 is configured in the standard astable oscillator circuit designed to give a square wave cycle at a period of around 1 cycle/sec. A potentiometer is included in the design so the period can be set to exactly 1 second by timing the LED flashes. A jumper connection is provided so the LED can be turned off. As soon as power is applied to the circuit counting begins. The output pulse from pin 3 of the 555 is fed to a the clock input pin 10 of the 14-stage binary ripple counter, the 4020 (or 14020.).

High-wattage appliances like electric irons, ovens and heaters result in unnecessary power loss if left ‘on’ for hours unnoticed. Here is a circuit that senses the flow of current through the appliances and gives audible beeps every fifteen minutes to remind you of power-’on’ status. This is a non-contact version of current monitor and can sense the flow of current in high-current appliances from a distance of up to 30 cm . It uses transistors in the input to provide very high input impedance (1.5 T-ohms), very low input current (10 pA) and high-speed switching performance.

Small circuit, with which we can use to get rid of the standard switch and operate any type of load with a push of a tactile button. Voltage between 5 and 18 V DC ( depends on the operating voltage of the relay coil ) in terminal CN1. Output Current is 10A ( depends on relay contacts ) in terminal CN3 activated by external positive pulse or short-circuiting the terminal CN2. Circuit is protected against double pulses and rebounds.

Digital potentiometer with memory is a built around PIC 16F819 microcontroller that reads analog resistances, records them to memory and plays them back via digital potentiometer DS1267 chip. The memory buffer size and the playback speed can be adjusted.

Digital VGA switch for switching between two PC monitors with MAX465 IC.

Working with the interaction design team, a bunch of us at Teague have been tinkering with measuring water, analyzing usage data in realtime to affect behaviors, and storing it to see patterns over time. At the heart of the exploration was a need to cheaply measure water from the tap. Water meters vary quite drastically in price (from $250+ for industrial grade sensors to $6 for garden hose attachments that limit total usage based on rough estimates). We settled on a $20 water meter used for PC cooling systems (the INS-FM17N by Koolance) due to its accuracy, low price, small size, and electronic sensing method that could be easily measured by a microcontroller (such as an Arduino).

There are two stages: aboriginal one is dabbling and the additional one is fading. Back you accessible the aperture the ablaze turns on. You get central and abutting the door, but the ablaze stays on (delay stage) for an adjustable aeon of time (0-40 sec. for the ethics in the scheme, but you can calmly adapt that i.e. put a bigger capacitor) so you can see area to admit the key or do whatever you do back you get in the car, again fades abroad (fading stage) with an adjustable speed. If you affix the ACC wire (which is absolutely optional) back you about-face the key to ACC position the ablaze turns off (actually fades) alike if the dabbling date is not over (it cancels the adjournment stage).

Doorbell with 555 IC