February 2012

Air Quality Monitor

If you have an indoor gas heater, or solid or liquid fuel portable heaters, then they all draw oxygen from the atmosphere when fuel is being burnt. Even with a ”flued” gas boiler (furnace) or water heater, good ventilation is essential to prevent toxic build-ups of carbon monoxide, an invisible and silent killer that increases when accumulations of combustion by-products are not vented away properly.

Some heaters have oxygen depletion devices that monitor the flame’s quality of burning and cut off the supply when oxygen is diminished, but these are basic in operation only and cannot provide total user safety to the occupants.

Monitoring the quality of air can avoid the risk of health problems or even fatalities. This sophisticated Air Quality Monitor project is ideal for home, boat and caravan owners, or for checking almost any enclosed area. It samples the surrounding air and two solid-state sensors inside measure CO and CO2 levels. The monitor indicates both Carbon Monoxide (CO) and Carbon Dioxide (CO2) on a simple LED bargraph display, cleverly configured to show 15 levels of gas concentration. An audible alarm sounds when gas concentrations become too high. Standalone, self-contained unit with built-in DC fan. Mains plug-pack powered. PIC 16F88 microcontroller project with source code downloadable from our Library.

GPS Car Computer (Part 2)

This sophisticated project captures and displays a range of parameters in your car, using a GPS module to provide speed information in real-time, as well as over-speed alarm, fuel economy, distance and time to destination, altitude, latitude & longitude and compass bearing. Note that this project is not a “sat nav” design but data can be sent to your laptop via the built-in USB for interpretation by navigation and mapping software. Flash upgradeable, auto LCD brightness. PIC 18F4550-based.

Last month, we introduced our GPS Car Computer and provided full constructional details. In Part 2 this month, the usage and operation of the GPS Car Computer are described.

Web Server in a Box (Part 3)

 
This hugely successful project is endlessly adaptable for those wishing to be more adventurous with their home network, and in Part 3 this month customisation hints and tips are provided for advanced users to tweak the design to their own requirements.

Web Server in A Box SD card update

An update to the original design, to allow another more readily-available SD card holder to be used in association with a small daughterboard.

Programming PICs: How It’s Done

Many projects are PIC-based and kits are frequently available to make life easier. If you’d like to program your own PIC microcontroller though, then this straightforward article shows you step by step what’s involved in a fully illustrated feature. If you’ve never done it before, this is a must-read!

Recycle-It – Wind-powered LED flasher

Following on from last month’s article (a wind-powered beacon) this month we present a wind-powered LED flasher, made literally from scrap. It uses an inductive circuit derived from a magnet and old solenoid mounted on a VCR bearing – no batteries, flashing circuit or control system are needed.

Also in this month’s EPE Magazine:

• Techno Talk on some recent technology developments at MIT
• Max’s Cool Beans  blog
• Interface – analogue-to-digital conversion, for PC enthusiasts wanting to do more with their computer
• Ingenuity Unlimited – LRC beat-balance metal detector
• PIC n MIX – using 5V LCDs with 3.3V processors
• Net Work – the Internet column – Logitech’s HD webcam, QR codes, sending large files by email and more practical tips.