June 2007 Issue
A summary of this month's contents.
Listen in to the sounds of bats and discover their secretive world, using our simple Bat sonar project. The circuit is a very sensitive ultrasound amplifier using a piezo input device to drive a preamplifier and frequency divider. The result is a human-audible signal that is output via a loudspeaker. Thus the ultrasonic signals of bats (and more besides) may be monitored at a level suited to the human hearing range.
Included in the article are details and hints to adapt the circuit for a simple 'sonar' system and an ultrasonic remote receiver.
3V to 9V DC Converter
What a great idea! Never buy another 9V PP3/ 1604 battery again. This DC converter is an electronic switching regulator circuit that steps up a low voltage to a higher one. Two AA cells (3V) are all that are required to produce a 9V output, with up to 7 hours of continuous operation available from a pair of AA 2000mAh cells.
The project will operate from AA, C or D cells. Up to 90mA current at 9V output, but can be set for 4.5V to 20V operation. The 3V Converter supports DC plugpack input and has an optional trickle charge for NiCD and NiMH batteries.
Energy Meter (Part 2)
Energy Meter (Part 2) — monitor electricity consumption and costs with this PIC-powered project. LCD readout of power in Watts, energy usage in kWh, period in hours, energy cost in Pounds Sterling or Dollars. Also includes unique Brownout Protection to guard against damaging low voltage dips. Full constructional details are supplied along with free source code available from our Downloads section. Construction and calibration procedures are described this month.
WARNING — HIGH VOLTAGE PROJECT WORKING DIRECTLY AT MAINS VOLTAGES — FOR SKILLED AND EXPERIENCED CONSTRUCTORS ONLY.
PCB artwork pcb0607.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.