Winter Logger

One of the (many) weird quirks of studying in the University of Cambridge is that our terms only last 8 weeks. Yes, the number of days we are officially “studying” is less than the number of days we are ostensibly on “holiday”. Of course, it never works that way, and Cambridge is probably one of the only places where going to uni feels exactly like going to secondary school. Over these long break, we are told that our rooms are going to be used for conference purposes, and that we would have to move all our stuff out to a tiny, cramped storage container....

January 30, 2023 · 20 min · Infinus

I2C EEPROM Tester with CircuitPython on a Raspberry Pi Pico

As part of the Winter Logger project, I got myself some DIP EEPROMs from eBay which were ostensibly AT24C256’s, mostly because I didn’t feel like buying yet more stuff that I probably would never use just to pad out Mouser’s £33 for free shipping minimum order. This is what I got: Suspicious… With all the counterfeit semiconductors floating out there, I wanted to verify if I at least had functional EEPROM that wasn’t literally just plastic with some legs tacked onto it - I wanted to test if all the memory cells actually worked....

November 12, 2022 · 4 min · Infinus

Inline Microphone Preamp

This is an attempt to try to get more signal out of dynamic microphones, as I literally have to max out the gain on my Presonus AudioBox iTwo to barely get a usable signal level, and that is with me speaking right on top of the microphone. This design is based on Project 66 by Eliott Sound Products , with some minor modifications, mostly me just playing around to see what are the effects of changing stuff around....

April 28, 2022 · 1 min · Infinus

Milk Jug Patch Antenna

This is not really a “project” in and of itself. Rather it’s a small experiment that me and my buddy Chris ran to investigate two things: Just how well do the figures coming out of the Patch Antenna Calculator that I botched together translate into the real world. How does bending the patch antenna (such as conforming it around a rocket tube) affect its parameters. The antenna itself This antenna was born on a chilly Friday night, in a generic teaching room in Lucy Cavendish College here in Cambridge....

March 29, 2022 · 4 min · Infinus

Battery Powered +48V Phantom Power Supply

The good, and perhaps bad, thing about passions and hobbies is that the energy to zealously pursue them ebbs and flows as the days, weeks, months or even years go past. Just recently, I experienced a strangely strong desire to just go out there and design something again out of frusration over what we’re “learning” at university, so here we are. Preface: Why LCSC Because DigiKey/Farnell/RS wouldn’t give me free shipping until I spent tonnes of cash, and even then, the VAT here in the UK is just crazy… It’s times like this when I really, really miss being in Malaysia....

February 25, 2022 · 7 min · Infinus

ESP Practice Amplifier

This is my attempt to try building this power amplifier from Elliott Sound Products , which was specifically designed to be a practice amplifier, in the sense that it allows electronics enthusiasts like us to practice our building and bug-tracking skills, and also to try modifying the circuit to learn some analog electronics. I had a lot of fun building this amplifier and attempting to do some measurements on it, and I hope you will enjoy this slightly more lab-notes style post....

December 29, 2021 · 12 min · Infinus

Inductor Saturation Current Measurement Jig and Constant Current Dummy Load

Background As I have only recently come to realize, inductor selection for boost converters is not a trivial matter at all. Every inductor I tried saturated way too early, causing progress for the SMPS Chronicles Boost Converter project to grind to a halt. After many frustrating afternoons, and several blown parts and melted breadboard holes, I had enough. Background As I have only recently come to realize, inductor selection for boost converters is not a trivial matter at all....

August 23, 2021 · 14 min · Infinus

Switched-Mode Power Supply Chronicles I: Op Amp Based Boost Converter

The inspiration for this series of articles came from Microchip’s TB3103 and TB3104 , which outlined the implementation of current mode controlled buck and boost converters using the PIC16F753’s internal analog peripherals, which include an operational amplifier, a comparator, PWM, etc. As a hobbyist, I’ve always found stuff like transfer functions, bode plots (the more complex ones), and SPICE to be really intimidating. I am aware of what these are, and why they are used in circuit design, but I’ve never really sat down and worked with them before, much less explore their nitty gritty details....

August 10, 2021 · 6 min · Infinus

STM32 Based MIDI Controller

If you do orchestral programming, you know that MIDI faders are absolutely essential to achieve a sound that wouldn’t be passed of as “MIDI-like”. What happens when you really, really want a MIDI controller with a bunch of faders, but don’t feel like spending *that much* money on one? Well, you build one. In this series of posts, I will present my take on the DIY MIDI controller, which has 4 faders, 4 rotary encoders, and a 4×4 key matrix, all of which are fully programmable via an onboard LCD....

May 20, 2021 · 4 min · Infinus