Solar Water Heating System Controller (Part 1)

Presenting a new “zero carbon” PIC-controlled system for managing solar heating panels. More than 30 years ago we published a controller for solar hot water systems, but 21st Century technology has transformed the science – and necessity - of saving energy out of all recognition.

This new design offers features that you will not find on a commercial controller: it needs no mains supply, produces no CO2 output in use and is considerably cheaper than ready-made solutions. It will operate with almost any solar water system including swimming pool heating, though some minor software changes may be needed using the information provided.

 

Part One this month describes the principles of operation, with circuit diagrams and parts list.  In the July 2009 issue we cover assembly, testing and calibration.

 

Spectacular Bike Wheel POV Display

A dazzling “spoketacular” bicycle display is yours with this amazing LED bike wheel display! Utilising the phenomenon of human persistence of vision (POV), these LED ‘spokes’ fit within a 26” bicycle wheel and display an image ‘in thin air’ as you cycle along.

 

Our PIC-powered project uses three double-sided boards to drive no less than 192 LEDs in three boards radiating out from the axle. Can be programmed with your own bitmap – anything from geometric shapes to logos, text, cartoon characters and even very high contrast characters using ‘reversed-out’ graphics on a constantly illuminated background. Fits a 26” wheel or larger, three pcbs required.

 

Remote Volume Control & Preamplifier Module (Part 1)

This advanced and up-to-date control module works with any universal infrared remote, and features a blue 7-segment LED readout and an optional rotary encoder. Its ability to both attenuate or amplify means that it can function as a simple volume control or a high performance stereo amplifier. All assembly and operation details are included in our fully featured constructional article, with construction, set-up and testing instructions in Part Two next month.

 

Breadboarding Projects (Part 9)

Our beginner’s guide to simple, solder-free project experiments continues with a Lightning Detector, based on a ‘radio on a chip’ to warn of the possible likelihood of lightning discharges or thunderstorms.

 

Solderless breadboards allow you to experiment with plug-in components without the need to solder joints. It’s a safe, low cost way to get started in electronics and components can be re-used again and again. Full details of circuit assembly are included in our tutorials. It’s a great way for beginners to learn!

 

Also in the June 2009 issue:

 

• Techno Talk on the perils of sourcing obsolete components
• Recycle It! How to make a human-powered LED torch for next to nothing
• Interface – our PC computer column sheds light on how to read text strings from a serial port
• Circuit Surgery – our in-house surgeon describes the theory behind triac fuses and I²R heating
• PIC n MIX – our PICmicro primer by Mike Hibbett continues with more on video generation
• Net Work – the Internet column - Internet Explorer 8 is arriving, and British reactions to Google’s Street View.

 

Source code 0609.zip (PIC n MIX Video article)

PCB files pcb0609.zip

 

Bike Wheel POV Display

Visit the author's website here to download more photos, code etc.