Marc's Public Blog - Electronics Hacking

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Table of Content for electronics:

2025/12/22: Rescueing a Netgear Gigabit Switch (single page)
2025/12/20: Dimming and Blinking Ferry Lights for Kandi (single page)
2025/10/31: Pasadena Hackaday Supercon 2025 (single page)
2025/10/10: 3600 More LEDs with Pixelblaze: 60x60 Matrix (single page)
2025/07/14: New TrancefamilySF Neopixel EDM Festival Hats (single page)
2025/03/07: Party LED Outfit Version 7: USB Powerbanks Powered Flexible LED Panels, LED Hat, and LED Shoelaces (single page)
2025/01/18: Extended Festival LED Shoes Version 4 (single page)
2025/01/17: House Lights with Pixelblaze on ESP32 monitored with Raspberry Pi (single page)
2024/11/20: Festival Dreamstate Hat Built with RGBPanel, Neopixels, and Lipos (single page)
2024/11/10: Getting Things Done in an ADHD World (single page)
2024/11/02: Pasadena Hackaday Supercon 2024 Yo Dawg Micro SAO and SMD Soldering (single page)
2024/11/01: Pasadena Hackaday Supercon 2024 (single page)
2024/11/01: Pasadena Hackaday Supercon 2024 SAO Badge (single page)
2023/09/22: Testing 1.5V AA Lithium Batteries (single page)
2023/08/29: 2023 Burning Man Illuminaughty LED Meetup (single page)
2023/06/16: Party LED Outfit Version 6: Self Contained Power System on LED Panels (single page)
2023/05/17: Party LED Outfit Version 5.5: Flexible P15 LED Strings, LED Fanny Pack, Rez Inspired LED Goggles, LED Laces and LED Shoes (single page)
2023/04/07: Managing a chicken coop door and checking water level with RC Plane Servo and ESP8266 (single page)
2023/01/10: The fun of solar garden lights (single page)
2022/11/28: Comparing Newer LED Flashlights (single page)
2022/01/09: LED Pants and Shirt v5 on ESP32 and Raspberry Pi with P2 RGBPanels and Wifi (single page)
2020/05/04: Hacking Power Supplies and Battery Pack To Get Around ThinkPad P73 Broken Power Supply Design (single page)
2020/01/14: Linux.conf.au Open Hardware Miniconf 2020: Dingo Car with Tensorflow Video Analysis v2 (single page)
2019/12/01: Using a Tesla Model 3 as Emergency Power Source In Case of Grid Failure (single page)
2019/04/09: Trying Diffusers for RGB Panels run by SmartMatrix::GFX (single page)
2019/01/24: Linux.conf.au 2019: Using Open Hardware from my shirt to OS testing for Google's Fuchsia (single page)
2018/06/30: DC charging with DC to DC conversions when off the grid (single page)
2018/05/29: EDM Party Shirt powered with FastLED::NeoMatrix and Adafruit::GFX, plus 160Wh (10Ah/4S) worth of lipos (single page)
2017/06/02: LED Pants and Shirt Programmed With Arduino on ESP8266 (single page)
2017/04/03: Arduino 328P Uno Teensy3.1 ESP8266 ESP32 IR and Neopixels (single page)
2016/05/24: Hacking LED Shoes (single page)
2016/02/29: Hacking a thinkpad slim tip adapter to output more than 90W (required to charge a Thinkpad P70) (single page)
2015/11/22: Solar Powered Lights Shed (single page)
2015/10/29: Controlling 5 and 12V swtiching with SmartFPV RCCCv2 Video Switching Board (single page)
2011/08/05: Hacking a Lipo Voltage Meter on a Ladyada Breadboard Power Supply (single page)
2011/07/01: Back Into Electronics (single page)
2011/05/06: PC/Breadboard Xbee Adapters: Sparkfun and Adafruit (single page)
2010/06/18: Powering UPSes with Marine or AGM batteries (single page)

More pages: December 2025 October 2025 July 2025 March 2025 January 2025 November 2024 September 2023 August 2023 June 2023 May 2023 April 2023 January 2023 November 2022 January 2022 May 2020 January 2020 December 2019 April 2019 January 2019 June 2018 May 2018 June 2017 April 2017 May 2016 February 2016 November 2015 October 2015 August 2011 July 2011 May 2011 June 2010

2025/12/22 Rescueing a Netgear Gigabit Switch

π 2025-12-22 01:01 in Electronics

I had a perfectly good netgear switch where the small fan was slowly failing and making lots of noise. No problem, I have boxes a fans, one of them will fit with a bit of help :)
Except as I change the fan, the switch does not turn on anymore, and my multimeter shows the built in power supply chose that exact time to fail. No more 5V power coming out = no more happy switch:

this will more or less fit :)

nothing really looked wrong, but the power supply was dead

So I ripped out the power supply, connected a 2.5mm jack female, and now any external 5V power supply will do the job:

new fan spinning on happy switch

back online

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2025/12/20 Dimming and Blinking Ferry Lights for Kandi

π 2025-12-20 01:01 in Clubbing, Electronics

Lots of lovely kandi is lit up those $1 ferry lights that take 2 CR2032 3V batteries which are difficult to replace (small screws) and non rechargeable. After being donated a beautiful DS kandi, I managed to break off the battery holder part by mistake, so I quickly adjusted it to use a JST 2 pin plug that is standard for all my builds. From there, I was able to plug it directly in a 3.8V lipo but those lipos output lots of amps with no internal resistance, so the lights were super bright and the big lipo was not going to last more than few hours.

The solution was to find the right dimming/blinking controller, which was quite hard to locate (didn't want to build my own). Uper right is most of the ones I found, they were too big, did dimming but not blinking, also they were USB based, so I have to solder JST connectors. Lower right is a better version, still USB only, although at least it had flashing. And then I finally found the right ones, bare wires, easier to just solder in my JST connectors, and they support flashing and blinking:

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