March 2022

Mini Isolated Serial Link

This tiny module, no bigger than a postage stamp, provides bidirectional, opto-isolated, full-duplex serial data communication. That makes it ideal for situations when two (or more) boards running from separate supplies need to exchange data with each other. The project can also carry isolated logic signals. Easy to build.

‘Busy Loo’ Warning

Ideal for beginners, this little circuit is designed using traditional CMOS logic to create an LED flasher that’s battery powered and has very low current consumption. It’s triggered into operation using a magnetic switch. Easy to build.

Battery Monitor Logger (Part 2)

Continuing with the construction of our Micromite Colour Touchscreen LCD-Backpack powered 6-100V power supply logger, the assembly and programming are described this month.

Surface mount devices are used and good soldering skills are required to complete this project successfully.

Electronic Wind Chimes (Part 2)

Last month the principles of operation were described along with details of the electronics construction. In Part 2 we look at the mechanical aspects, detailing how to add an array of solenoid strikers to your windchime.

Geekcreit LCR-T4 Digital Multitester

It’s almost impossible to believe, but the LCR-T4 tester is available from Far East internet suppliers for just a few pounds. The multitester will identify, check and analyse a very wide range of discrete components, before displaying its findings on a mono graphical LCD. All manner of components can be checked and verified, including resistors, capacitors, BJTs, LEDs and much more besides. No hobbyist can afford to be without one – check this month’s issue to find out more!

Audio Out
Analogue Vocoder (Part 5): Building the filter

This month’s column gets down to the nitty-gritty of construction – the six band-pass filter cards and a high-pass/ low-pass filter. Built using standard discrete components throughout. The article contains many photos and practical details thaty will enable constructors to tackle assembly confidently.

Electronic Building Blocks

A cheap and cheerful way of making a set of amplified speakers for your laptop. Based on a low-cost kit from the Far East.

Also in this issue:

• Techno Talk – the perils heading our way when the UK phone network changes to digital VoIP
• Net Work – Facebook’s future in the ‘metaverse’, more EV news and a floating nuclear power station
• Circuit Surgery – Our in-house ‘surgeon’ follows up on the in-depth analysis of op.amp offsets.
• Max’s Cool Beans – Flashing LEDs and drooling engineers (part 25) – more progress to report on the animatronic robot head project
• Make It with Micromite – Part 34: using the Micromite with an EEPROM iButton

In next month’s issue:

Digital FX Unit (Part 1); High-current Battery Balancer; 64-key Arduino MIDI matrix (Part 1); KickStart – Raspberry Pi Pico.