High Quality Digital Audio Signal Generator (Part 1)

This sophisticated digital test gear has a backlit LCD display and TOSLINK and coax S/PDIF digital outputs with two analogue audio outputs as well.

Generates sine, square, triangle and two sawtooth waveforms, 1Hz to 24kHz.  THD 0.06% (internal DAC) or 0.0006% (ext DAC). Switch between S/PDIF 20-bit and AES/EBU 24-bit modes. Ten memories for storing settings. Many more features too numerous to list here! PICmicro PIC33FJ based. In Part 2 next month, assembly is described.

Accurate Thermometer/ Thermostat

This LCD Thermometer/ Thermostat measures from -55°C to + 125°C with accuracy up to 0.5°C.  Twin relay NO/ NC outputs with audible alert for over or under temperature. Informative backlit 2-line LCD. Based on a Dallas temperature sensor DS18B20, controlled by a pre-programmed Atmel MCU.  Remote sensor can be mounted 300mm away.

Internet Time Display Module

A simple add-on for the hugely-popular Web Server in a Box, it shows local time and date derived from an Internet time server on a 7-segment LED display. Static or scrolling displays. You can use it as a clock you never need to adjust and it can be configured in the WiB for DST. PIC 18F based.

Solar-powered Intruder Alarm

Have you got a garage, shed, or boat on a mooring somewhere? This solar-powered alarm system is an ideal form of self-contained intruder protection for remotely-located properties. Uses a solar-powered trickle charger in conjunction with a sealed lead-acid battery. Discrete component circuit. Compatible with common reed switches or pressure mats, it has three inputs including one low-power PIR input, entry and exit delays and a MOSFET output driver for a siren.

Also in this issue:

• Circuit Surgery – more on the mathematics of digital waveform generation
• Net Work – the Internet column – on storing valuable files in the ‘cloud’ and capturing online TV or Youtube movies to hard disk.
• Techno Talk – trends in LED lighting
• Practically Speaking – more practical workshop tips for constructors
• Max’s Cool Beans blog ponders historical estimates of when the End of the World is nigh
• PIC n MIX – our PIC micro specialist looks at keenly priced Arduino boards from Microchip
• Ingenuity Unlimited – readers’ own circuit ideas.