23 April 2010

Last month, we described how the S/PDIF Digital Audio Signal Generator works. This month, we describe how to assemble the PC boards, mount them in the case and check that they are working correctly.

19 April 2010

Want to control something - anything - with commands from your PC? Perhaps turn sprinklers on and off to water your garden? Maybe read some sensors? Or even sequencing Christmas tree lights in time with music? (OK, so we're getting in early!) Making the computer output the correct information is one thing. Interfacing that data to control real-word devices is another. That's what this nifty little relay box is all about.

13 April 2010

Do you need to measure the EHT voltage in a CRT-based scope, computer monitor or TV receiver, or perhaps in a photocopier, laser printer or microwave oven? You'll need an EHT probe to suit your digital multimeter (DMM) to do this and you'll find they are pretty pricey. Not to worry though, because here's one you can build for less than $40.

09 April 2010

Here's a cut-down version of the Digital Capacitor Leakage Meter we described in December 2009. Instead of using a PIC microcontroller and an LCD panel to display the leakage current, this version connects to your DMM to provide the readout. It provides the same range of seven different standard test voltages (from 10V to 100V) and can measure leakage currents down to 100 nanoamps!

19 March 2010

Based on the very accurate Dallas DS18B20 digital temperature sensor, this thermometer/thermostat provides accurate readings to one decimal point. The LCD shows current, minimum and maximum temperature readings. An internal buzzer will sound when temperature limits are exceeded. It is intended for controlling air conditioners, heaters, cool rooms, wine cellars, etc. The software is user-customisable.

12 March 2010

This neat little adaptor allows a standard digital multimeter to measure low values of capacitance - from less than one picofarad to over 10nF. It will allow you to measure tiny capacitors or stray capacitances in switches, connectors and wiring.

08 March 2010

This Digital Audio Signal Generator has TOSLINK and coax (S/PDIF) digital outputs, as well as two analog audio outputs. If a digital output is used, the harmonic distortion from a high quality DAC is extremely low. Alternatively, if you use the analog outputs the harmonic distortion of the sinewave signal is typically still very low at less than .06%.

06 March 2010

Most blokes have got a shed - or wish they had! While many people have alarms for their home and cars, a lot of valuable stuff is unprotected in garages and sheds. It needs protecting and now you can do it with this simple alarm based on a PIR sensor. It's solar-powered so no mains supply is needed. And let's not forget boats on moorings - they need protecting too.

19 February 2010

Last month, we introduced our new GPS Car Computer and provided full constructional details. But there's a lot more that we haven't covered yet . . .

15 February 2010

Looking for a really accurate clock? This simple add-on board for the WIB (Web Server In A Box) displays the time and date, as gathered from an internet time server. You can use it as a clock you never need to adjust and it can even be configured in the WIB to automatically adjust for daylight saving time.