March 2023

This month’s highlights

Capacitor Discharge Welder (Part 1)



Now you can make your own battery packs or thermocouples using this safe, low-voltage mini spot welder. It generates enough energy to weld nickel strips onto individual cells to create custom battery packs, or you can use it to spot-weld K-type thermocouple tips together for producing bespoke thermocouples.  The weld energy is adjustable from a few joules up to 208 or 365J with variable pulse duration. A number of safety features ensures the Capacitor Discharge Welder is safe to use. Part One this month examines the circuitry with construction following in Part Two next month.

  Constructors must follow closely the safety warnings that are clearly printed in the article (p.18). Not to be used by those wearing a heart pacemaker or any similar sensitive medical device.

Raspberry Pi Pico BackPack

This useful project adds a colour LCD touchscreen to the Raspberry Pi Pico, opening up many new possibilities for more advanced and versatile applications for this ever-popular single board computer. Details of some demo and test programs are included.

Semaphore Signal for OO-gauge Model Railways

Inspired by a British railway semaphore signal, this OO-scale signal has an authentic-looking tilting red/ white flag and red/ green LED indicator to add realism to your model railroad layouts. Full construction diagrams are included.

Also in this issue:

  • Techno Talk – after 20 years at the helm, Mark Nelson signs off his last Techno Talk column this month with a final roundup of emerging technology oddities.
  • The Fox Report – how a well-known London venue unwittingly fell victim to an Email hack
  • Net Work – a bumper column this month brings more news of the UK’s micro satellite launching ambitions, and highlights the work of Paul Otlet (1868 – 1944), arguably the father of the Information Age.
  • Audio Out – our analogue audio expert tests out the Handyscope HS5 USB oscilloscope
  • Make it with Micromite – Part 45: Updating the PicoMite firmware
  • Circuit Surgery – continuing the theme of electronically-controlled resistance (Part 7)
  • Max’s Cool Beans – Arduino Bootcamp (Part 3) – getting started with the Arduino: first steps in coding.

Next month:

Amplifier Clipping Indicator; Capacitor Discharge Welder (Part 2); Improved SMD Test Tweezers; Three Low-Noise HF-UHF Amplifiers. Contents may be subject to last-minute change.

March 2023 files for download -


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