March 2012 Issue

A summary of this month's contents.

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 – mor eprqctical 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.

 

EPE is the No. 1 UK magazine for electronics technology and computer projects – you can download the Internet-only edition or subscibe to a hard copy version, delivered anywhere in the world.

 

 

Source code 0312.zip

PCB files pcb0312.zip

 

 

Accurate Thermometer/ Thermostat

A complete kit is available from Altronics.

 

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