October 2023

Automatic Level Crossing and Semaphore Control for model railroads

This constructional project combines the Model Railway Level Crossing and Semaphore Signal projects with a Li’l Pulser Mk. 2 train controller to automate a model railway layout. It also adds chuffing and whistle sounds for added realism. Now your train will pull up to the semaphore signal, triggering the level crossing then proceed through the crossing when it’s safe – complete with sound effects! Uses a PIC 16F1455 and 12F675 MCU with source code available to subscribers.

• See it in action at this video URL: https://bit.ly/pe-oct23-loco

Multi-stage Buck-Boost Battery Charger

This simple, low-priced add-on turns our Buck-Boost Driver into a fully-featured multi-stage battery charger. Suitable for multiple battery chemistries and especially useful for lead-acid types. It outputs from 7V to 34V, up to 8A and is suitable for most 12V and 24V batteries. A compact OLED display shows configuration and status.

Introducing new PICs and AVR from Microchip, plus breakout boards

The parts shortage in recent years has given us the incentive to look more widely for alternatives. Newer devices have more features and at a lower cost too, so we were keen to explore the latest components and see what they have to offer. We offer three breakout boards to help utilise them.

Audio Out – a low noise discrete audio op.amp (Part 2)

This month the discrete op.amp circuit is explained.

Please Take Note: p46 lists corrections needed to the circuit diagram published last month.

Also in this issue:

• Techno Talk – the Sphere building in Las Vegas, see https://youtu.be/wKCY1Ph7T0k
• Net Work – the rise in facial recognition and ‘payment by face’, dealing with old banknotes and Voyager 2 wakes up again
• Max’s Cool Beans – Arduino Bootcamp (Part 10) – more Arduino hints, tips and coding for beginners
• KickStart – Part 13: Using low-cost colour LCD displays with the Raspberry Pi Pico
• Circuit Surgery – Gyrators (Part 2). Using these fascinating circuits in equaliser circuits.

Next month

LC Meter Mk3; DC Supply Filter for vehicles; PM (Particulate Matter) ‘Dust’ Sensors; Discrete audio op.amp (Part 3). Contents subject to change.