October 2007 Issue
A summary of this month's contents.
Save power and do your bit to save the planet! Our Standby Power Saver remotely turns off TVs, DVDs, amplifiers etc. at the press of a button. The system consists of two units — a handheld transmitter and a mains appliance controller. It operates on the (UK legal) 433 MHz radio frequency and uses readily available ready-made RF modules.
Having electrical appliances such as TVs idling on standby for long periods is known to be unnecessarily wasteful so our Standby Controller lets you completely power them down when they are not required.
At basic level, the system comprises one transmitter controlling a single receiver. It is possible to control up to 64 receivers, jointly or independently. PIC 16F627 powered.
Introducing a digital doorbell with a difference! Our specially programmed microcontroller-powered project is "tuned" to imitate the familiar rumble of a V8 engine block. It also includes a V-shaped LED indicator that light up in sync with the sound for added effect. By adding an extra sound pipe (as per photo), a realistic deep V8-like rumble with ambient noise effect can be achieved.
Incorporates built-in amplifier and speaker, plus line-out. 12V operated (of course), and be sure to use unleaded solder when building it :-)
Build your own seismograph
Our design uses a horizontal swinging pendulum to detect earthquake waves, and you can even display the results on your PC. Movement is detected by a heavily damped pendulum that has a light sensor mounted at one end. A metal vane modulates the light received by an opto-detector. The resultant signal is captured by a data logger, and the data can be stored, displayed and printed in graphical form using a PC and a freeware graphing program.
The unit is centred on a PICAXE-08 based A/D converter, and full constructional details and quality photography means that you can build this design with confidence.
Inductance and Q Factor Meter (Part 1)
This unique projects demonstrates what can be achieved with a relatively simple circuit and some clever programming. With only an ATMEL microcontroller and a handful of components, it functions as a wide range multifrequency inductance and Q-factor meter. Internal or external tank capacitance facility for accurate Q measurements. Measurement frequency autoranging up to 20MHz. Range 200nH - 10mH. Q: 1-120 approx.
Source codes 1007.zip
PCB artwork pcb1007.zip
As from July 2013 issue PCB artwork is available free to subscribers only.
Non-subscribers may purchase artwork files for a nominal sum. Please contact our Orders Dept for information or to place an order.
EPE Printed Circuit Boards
We can supply ready-made printed circuit boards (8-digit order codes) to the original design specification via mail order or from our Online Shop.