Those of you who imagine that a robot voice generator box would require a whole heap of ICs are mistaken; the ISD2500 ChipCorder family of ICs from Winbond contains almost all the necessary hardware in a single IC to record and playback audio messages. Included on the IC is a microphone preamp and AGC suitable for a low-cost electret type microphone, an output amplifier to drive a loudspeaker, memory, an oscillator, an A/D and a D/A converter.

At the heart of this overhead detector (fire alarm) circuit is a precision integrated temperature sensor type LM35 (IC1), which provides an accurately linear and directly proportional output in mV, over the zero to +155 degrees C temperature range. This can be used as part of fire smoke detectors but do not use it as a home fire alarm system.
The LM35 develops an output voltage of 10 mV/K change in measured temperature.
Designed to draw a minimal current of its own, the LM35 has very low self heating in still air.

Have your already set up a Christmas tree in your house and decorated it with traditional lights? Build a couple of these blinking Christmas decorations to enhance the Christmas mood. The coloured LEDs blink in a seemingly random sequence and rate and create a festive appearance.

This 3 volts Car Adapter circuit is based on a standard LT1074CT switching regulator IC. The schematic shows the LT1074CT used as a positive step-down or ‘buck’ converter.

The ‘switcher’ is used to convert a +12-volt car battery voltage down to +3 volts for use with the personal hi-fi’s and handheld games for the author’s two boisterous children on long car journeys. Note at under ten years of age, children will rarely be hi-fi aficionado’s and are generally not concerned with any noise generated by the ‘switcher ‘circuit.

Read the rest and view the 3volt car adapter circuit