September 2020

Ultrabrite LED Pushbike Light

This high power buck-converter based circuit is great for cycle use or as a torch (flashlight). It can power a 12V LED array from an 18.5V LiOn or LiPo battery and will operate from 5-25V. It delivers 1A or 2.2A and can be used with a wide variety of high-brightness LEDs including 6V and 12V types. Features include three brightness settings, flash mode, undervoltage lockout and overheat protection. Uses a dedicated switched-mode LED controller chip and a PICmicro 10F MCU with source code available for free download.

  Subminiature design uses surface mounted components, and very good soldering skills are needed to complete this design successfully.

The Micromite Explore-28

The 28-pin Micromite has been used at the heart of many of our projects in the last few years. The Micromite Explore-28 is a complete MCU module with a USB interface and power supply that’s programmed in BASIC. It’s like the popular Micromite LCD Backpack (May 2018) but without the LCD and in a package not much bigger than a 28-pin DIL IC. It supports a number of serial protocols as well as special devices like temperature sensors, keypads and IR remote controls.

  This design uses surface mounted components, and good soldering skills are needed to complete this design successfully.

Three Stepper Motor Drivers

Want to build your own hobby CNC machine or 3D printer? This article is a roundup of three common stepper motor drivers and how to use them in your projects, and assumes a prior knowledge of stepper motor basics.  (We published a series “Using Stepper Motors” in the October 2019 to February 2020 issues of Practical Electronics.)

PIC n’ MIX (Part 2): Software tools for the PIC18F

This month our PIC micro expert Mike Hibbett looks at software tools that are available for developing programs on Microchip PIC processors, focussing on the MPLAB X,

Make It With Micromite:
Building the Micromite Robot Buggy (MRB)

The final part of this super-interesting series polishes off the Micromite Robot Buggy (MRB) by equipping it with an obstacle avoidance system, in the shape of an ultrasonic distance module. The Micromite code is available for free, bundled in this month’s downloadable file.

Max’s Cool Beans: Flashing LEDs and drooling engineers (Part 7)

Max presses ever onwards and upwards with his 12×12 ping pong ball LED array

Audio Out
Low-noise Theremin Power Supply (Part 2)

This month our Theremin developer Jake Rothman describes in detail the intricacies of actually building a high-performance, low noise Theremin power supply. Plenty of practical hints, tips and photographs are included in this major article.

Cheap and easy compact speaker enclosures

Want to build a loudspeaker enclosure but put off off by the woodworking involved? Julian Edgar describes a novel technique using clay-fibre flowerpots instead. They look stunning – and sound great too!

Also in this issue:

• The Fox Report – Barry Fox gives practical advice on techniques and pointers to the best software for rescuing and capturing analogue video and converting it to hard disk.
• Techno Talk – the history and merits of the RoKa connector, better known as a DC power connector plug
• Net Work – the Internet column – Alan Winstanley offers a roundup of things to consider before investing in an IP camera for your home.
• Circuit Surgery – Ian Bell takes a very close look at the operation of differential amplifiers.

Next month:

High power 45V/ 8A variable linear power supply, Arduino-based Digital Audio Millivoltmeter, Precision Audio Signal Amplifier and all the regulars. Contents may be subject to change.