Silicon ChipAn alternative version of the Arduino Power Supply - March 2022 SILICON CHIP
  1. Outer Front Cover
  2. Contents
  3. Publisher's Letter: RIP Brendan James Akhurst, cartoonist extraordinaire
  4. Mailbag
  5. Feature: The History of Transistors, part one by Ian Batty
  6. Project: Capacitor Discharge Welder, part one by Phil Prosser
  7. Project: Raspberry Pi Pico BackPack by Tim Blythman
  8. Feature: All About Batteries, part three by Dr David Maddison
  9. Serviceman's Log: The oven with a mind of its own by Dave Thompson
  10. Project: Amplifier Clipping Indicator by John Clarke
  11. Circuit Notebook: An alternative version of the Arduino Power Supply by Stephen Gordon
  12. Circuit Notebook: Illuminated doorbell press switch circuit by David Worboys
  13. Circuit Notebook: Reading three digital signals with a two-channel oscilloscope by John Rich
  14. Feature: Advances in Drone Technology by Bob Young
  15. Project: Dual Hybrid Power Supply, part two by Phil Prosser
  16. Feature: A Gesture Recognition Module by Jim Rowe
  17. Vintage Radio: Phenix Ultradyne L-2 by Dennis Jackson
  18. PartShop
  19. Ask Silicon Chip
  20. Market Centre
  21. Advertising Index
  22. Notes & Errata: Vintage Radio, February 2022; USB Cable Tester, November & December 2021
  23. Outer Back Cover

This is only a preview of the March 2022 issue of Silicon Chip.

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Articles in this series:
  • The History of Transistors, part one (March 2022)
  • The History of Transistors, Pt2 (April 2022)
  • The History of Transistors, Pt3 (May 2022)
Items relevant to "Capacitor Discharge Welder, part one":
  • Capacitor Discharge Welder Power Supply PCB [29103221] (AUD $5.00)
  • Capacitor Discharge Welder Control PCB [29103222] (AUD $5.00)
  • Capacitor Discharge Welder Energy Storage Module PCB [29103223] (AUD $2.50)
  • IRFB7434(G)PBF‎ N-channel high-current Mosfet (Source component, AUD $5.00)
  • Hard-to-get parts & PCB for the Capacitor Discharge Welder Energy Storage Module (ESM) (Component, AUD $20.00)
  • Hard-to-get parts & PCB for the Capacitor Discharge Welder Power Supply (Component, AUD $25.00)
  • Validation spreadsheets for the CD Spot Welder (Software, Free)
  • Capacitor Discharge Welder PCB patterns (PDF download) [29103221-3] (Free)
Articles in this series:
  • Capacitor Discharge Welder, part one (March 2022)
  • Capacitor Discharge Welder, Pt2 (April 2022)
Items relevant to "Raspberry Pi Pico BackPack":
  • Raspberry Pi Pico BackPack PCB [07101221] (AUD $5.00)
  • DS3231MZ real-time clock IC (SOIC-8) (Component, AUD $10.00)
  • DS3231 real-time clock IC (SOIC-16) (Component, AUD $7.50)
  • 3.5-inch TFT Touchscreen LCD module with SD card socket (Component, AUD $35.00)
  • Raspberry Pi Pico BackPack kit (Component, AUD $80.00)
  • Matte/Gloss Black UB3 Lid for Advanced GPS Computer (BackPack V3) or Pico BackPack (PCB, AUD $5.00)
  • Matte/Gloss Black UB3 Lid for Micromite LCD BackPack V3 or Pico BackPack using 3.5in screen (PCB, AUD $5.00)
  • Raspberry Pi Pico BackPack software (Free)
  • Raspberry Pi Pico BackPack PCB pattern (PDF download) [07101221] (Free)
Articles in this series:
  • All About Batteries - Part 1 (January 2022)
  • All About Batteries – Part 2 (February 2022)
  • All About Batteries, part three (March 2022)
Items relevant to "Amplifier Clipping Indicator":
  • 500W Amplifier Module PCB [01107021 RevD] (AUD $25.00)
  • Hard-to-get parts for the 500W Amplifier (Component, AUD $200.00)
  • 500W Amplifier Module PCB pattern (PDF download) [01107021] (Free)
  • Amplifier Clipping Indicator PCB [01112211] (AUD $2.50)
  • Amplifier Clipping Indicator PCB pattern (PDF download) [01112211] (Free)
Articles in this series:
  • Fan Controller & Loudspeaker Protector (February 2022)
  • Amplifier Clipping Indicator (March 2022)
  • 500W Power Amplifier, Part 1 (April 2022)
  • 500W Power Amplifier, Part Two (May 2022)
  • 500W Power Amplifier, Part 3 (June 2022)
Items relevant to "Dual Hybrid Power Supply, part two":
  • Intelligent Dual Hybrid Power Supply PCB set (AUD $25.00)
  • Intelligent Dual Hybrid Power Supply regulator PCB [18107211] (AUD $7.50)
  • Intelligent Dual Hybrid Power Supply front panel control PCB [18107212] (AUD $2.50)
  • PIC32MZ2048EFH064-250I/PT programmed for the Intelligent Dual Hybrid Power Supply [0110619A.HEX] (Programmed Microcontroller, AUD $30.00)
  • 128x64 Blue LCD screen with KS0108-compatible controller (Component, AUD $30.00)
  • Hard-to-get parts for the Intelligent Dual Hybrid Power Supply regulator board (Component, AUD $125.00)
  • Hard-to-get parts for the Intelligent Dual Hybrid Power Supply CPU board (Component, AUD $60.00)
  • LCD panel bezel for the Dual Intelligent Hybrid Power Supply (PCB, AUD $5.00)
  • Intelligent Dual Hybrid Power Supply firmware [0110619A.HEX] (Software, Free)
  • Intelligent Dual Hybrid Power Supply PCB patterns [18107211/2] (Free)
  • DSP Active Crossover/DDS/Reflow Oven PCB patterns (PDF download) [01106191-6] (AUD $3.00)
Articles in this series:
  • Dual Hybrid Power Supply – Pt1 (February 2022)
  • Dual Hybrid Power Supply, part two (March 2022)
Items relevant to "A Gesture Recognition Module":
  • MMbasic software for the PAJ7620U2 gesture recognition module (Free)
Articles in this series:
  • El Cheapo Modules From Asia - Part 1 (October 2016)
  • El Cheapo Modules From Asia - Part 2 (December 2016)
  • El Cheapo Modules From Asia - Part 3 (January 2017)
  • El Cheapo Modules from Asia - Part 4 (February 2017)
  • El Cheapo Modules, Part 5: LCD module with I²C (March 2017)
  • El Cheapo Modules, Part 6: Direct Digital Synthesiser (April 2017)
  • El Cheapo Modules, Part 7: LED Matrix displays (June 2017)
  • El Cheapo Modules: Li-ion & LiPo Chargers (August 2017)
  • El Cheapo modules Part 9: AD9850 DDS module (September 2017)
  • El Cheapo Modules Part 10: GPS receivers (October 2017)
  • El Cheapo Modules 11: Pressure/Temperature Sensors (December 2017)
  • El Cheapo Modules 12: 2.4GHz Wireless Data Modules (January 2018)
  • El Cheapo Modules 13: sensing motion and moisture (February 2018)
  • El Cheapo Modules 14: Logarithmic RF Detector (March 2018)
  • El Cheapo Modules 16: 35-4400MHz frequency generator (May 2018)
  • El Cheapo Modules 17: 4GHz digital attenuator (June 2018)
  • El Cheapo: 500MHz frequency counter and preamp (July 2018)
  • El Cheapo modules Part 19 – Arduino NFC Shield (September 2018)
  • El cheapo modules, part 20: two tiny compass modules (November 2018)
  • El cheapo modules, part 21: stamp-sized audio player (December 2018)
  • El Cheapo Modules 22: Stepper Motor Drivers (February 2019)
  • El Cheapo Modules 23: Galvanic Skin Response (March 2019)
  • El Cheapo Modules: Class D amplifier modules (May 2019)
  • El Cheapo Modules: Long Range (LoRa) Transceivers (June 2019)
  • El Cheapo Modules: AD584 Precision Voltage References (July 2019)
  • Three I-O Expanders to give you more control! (November 2019)
  • El Cheapo modules: “Intelligent” 8x8 RGB LED Matrix (January 2020)
  • El Cheapo modules: 8-channel USB Logic Analyser (February 2020)
  • New w-i-d-e-b-a-n-d RTL-SDR modules (May 2020)
  • New w-i-d-e-b-a-n-d RTL-SDR modules, Part 2 (June 2020)
  • El Cheapo Modules: Mini Digital Volt/Amp Panel Meters (December 2020)
  • El Cheapo Modules: Mini Digital AC Panel Meters (January 2021)
  • El Cheapo Modules: LCR-T4 Digital Multi-Tester (February 2021)
  • El Cheapo Modules: USB-PD chargers (July 2021)
  • El Cheapo Modules: USB-PD Triggers (August 2021)
  • El Cheapo Modules: 3.8GHz Digital Attenuator (October 2021)
  • El Cheapo Modules: 6GHz Digital Attenuator (November 2021)
  • El Cheapo Modules: 35MHz-4.4GHz Signal Generator (December 2021)
  • El Cheapo Modules: LTDZ Spectrum Analyser (January 2022)
  • Low-noise HF-UHF Amplifiers (February 2022)
  • A Gesture Recognition Module (March 2022)
  • Air Quality Sensors (May 2022)
  • MOS Air Quality Sensors (June 2022)
  • PAS CO2 Air Quality Sensor (July 2022)

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CIRCUIT NOTEBOOK Interesting circuit ideas which we have checked but not built and tested. Contributions will be paid for at standard rates. All submissions should include full name, address & phone number. An alternative version of the Arduino Power Supply I designed a slightly different version of the Arduino-based Power Supply from the February 2021 issue (siliconchip.com.au/Series/357). I wanted to remove the need to physically connect the power supply to my laptop, as that means that I need to find a spot for the laptop on my workbench, and there isn’t room. To do this, I based it around an Arduino-­ compatible ESP8266 module, specifically the WeMos D1 R2 mini. The main challenge in adapting the design to this module is that the micro has 3.3V I/Os compared to the 5V I/Os of an Arduino Uno. The circuit is overall similar to the February 2021 design, with the following changes. I added two transistors (Q3 & Q4) acting as a level shifter to switch the relay from the D1 mini’s 3.3V digital output. I also had to add a TMUX1204 4:1 analog multiplexer since the D1 mini only has one analog input. Sensing of supply voltage, output voltage and current are all done via this mux, which adds three extra analog inputs but takes up two digital outputs to select the mux channel. I added an AMS1117 low-dropout regulator to provide the 5V rail from the input power supply; this can handle an input voltage up to about 12V. Above that, a regulator with a heatsink like a 7805 would be needed. I enclosed all the circuitry in a Jiffy box with a voltmeter (since the laptop is not in the same room) and some nice binding posts. The voltmeter is mainly so that I can confirm it’s on the correct voltage before connecting things. The D1 mini module is connected to the PCB with most of the circuitry via 10x2-pin header CON1. This makes creating other daughterboards possible; I also created a board for an Arduino Nano, to provide a wired alternative that’s a little cheaper than the Uno. I have not tested that yet. The PC software acts as a server, waiting for the PSU to connect via WiFi. The PSU connects to the GUI on startup, and everything works the same as Tim Blythman’s original design once the connection is established. The PSU also listens for connections on port 23. Connecting to this allows the user to specify the IP of the GUI program that the PSU should attempt to connect to. The only other firmware modification required was to set the mux channel before reading voltages using the analog-to-digital converter. I discovered one flaw: for up to a minute after initial connection, the communication between GUI and PSU is very slow, and the PSU responds sluggishly. After that time, it responds more or less instantaneously. I am not sure why this happens – perhaps it’s a buffering issue in the D1 mini’s WiFi stack or a bug in the Processing language. Thanks for a terrific design! I learned a lot building this, and now I have a very convenient low-voltage PSU which is enough for many projects. The modified firmware and GUI code can be downloaded from https://github. com/gordoste/d1_mini_wifi_psu Stephen Gordon, Thurgoona, NSW ($150). Editor’s note: Q4 and two 10kW resistors could be eliminated by connecting the coil of RYL1b and D1 (D1 anode to +5V) between +5V and the collector of Q3. The finished PSU is composed of two PCBs and the D1 module. This photo shows how the main PCB is wired into the case. The finished Arduino PSU uses a 3-digit 7-segment digital voltmeter. 72 Silicon Chip Australia's electronics magazine siliconchip.com.au siliconchip.com.au Australia's electronics magazine March 2022  73