Monday, December 14, 2020

DIY 16-bit precision voltage source with MAX5717A DAC

If you need a precision voltage source, you have three options. You can spend thousands of dollars and buy a lab instrument from a reputable company, you can spend hundreds and get an amazing enthusiast-grade device from Ian Johnston, or... If you're a cheap ass like me, you can build your own device that might just be enough for your use case at a fraction of the cost, and with hours and hours of fun included for free. Guess what we're going to do!

Saturday, November 21, 2020

26 AWG solid copper wire: the perfect choice for hand-soldered Arduino projects

This post is my little token of appreciation for the 26 AWG solid core copper wire. Perfect for creating permanent version of Arduino projects, or if not perfect, then at least much simpler than wire wrapping and much, much more practical than using solder traces. Man, I love 26 AWG solid core.

Saturday, November 7, 2020

Using a FLIR thermal camera to improve the taste uniformity of a tea-infused cake

Making a layer cake is a serious task. There are... layers... of complexity to it. Make a mistake, miss a step, and the whole thing can turn into a disaster. 

Thursday, November 5, 2020

Quick look: Voltage drift / instability on Ruideng RD6006 power supply

This post is a quick record of voltage drift / variations I noticed during recent experiments with using a MOSFET as a voltage-controlled resistor, where the MOSFET's Gate-Source voltage was driven by the Ruideng RD6006(W) DC-DC power supply.

Sunday, October 18, 2020

TL-21 Kelvin clip test lead upgrade for DER EE E-5000 LCR meter

There's no shortage of blog posts and videos describing TL-21 probe upgrade for the extremely popular DER EE E-5000 LCR meter. With that said, this post will is somewhat repetitive, but hey, I already took the pictures, so why not share.

For impatient readers, this is what the finished job looks like:

Tuesday, October 6, 2020

Measuring NiMH vs Li-Ion voltage sag at small loads with ESP32

This article is a brief excerpt from my experience with using Nickel Metal Hydride (NiMH) and Lithium-ion (Li-ion) cells for powering home sensors running the ESP32 Wi-Fi microcontroller.

Measuring breadboard wiring resistance: how bad is bad?

This article is a brief record of my early breadboard wiring adventures, because learning things the hard way is fun! You may also read the related post if you wish:

Sunday, June 18, 2017

The story of MySQL Bug #86664

This is a story about why it's a good idea to test and verify the behavior of new software releases, even if the change log says that a particular bug was already fixed.

Wednesday, May 31, 2017

Database proof-of-concept & migration best practices

This post tries to answer some of the most popular questions I receive from customers, regarding the best practices for database proof-of-concept and migration projects.

Tuesday, October 4, 2016

Quick look: Performance impact of General and Slow Query Logging

General query logs and slow query logs remain one of the most popular sources of auditing and diagnostic information in MySQL databases. Customers often ask about the cost of general and slow query logging so I went googling for existing research I could point them to. The data I found was not quite what I hoped for, which is why I decided to do some more testing.