In this project you’ll discover how to design and create a Multisensor Shield for the ESP8266 Wemos D1 Mini board. The shield has temperature sensor (DS18B20), a PIR motion sensor, an LDR, and a terminal to connect a relay module. We’ll start by preparing all the hardware and then program it.
Russell Graves did teardown of a Craftsman 19.2V DieHard battery and a Ridgid 12V battery:
It’s time for more tool battery teardowns! This week, I’ve got a Craftsman 19.2V DieHard battery, and a cute little Ridgid 12V battery. They’re both lithium, and I’m going to dig into both of them, because that’s what I do with old batteries I pick up out of junk bins.
If you’re bored of tool battery teardowns, you could always send me more interesting things to mess with! I enjoy poking around tool batteries, and a lot of the ones I pull apart are “new to the internet” in that they haven’t had a detailed teardown before. It’s always interesting to see how different companies approach much the same problem.
Investigative app note from Richtek about the component failure point caused by EOS. Link here (PDF)
Failures in power ICs are often the result of Electrical Over Stress (EOS) on the IC input supply pin. This report explains the structure of power IC input ESD protection and how ESD cells can become damaged due to EOS. Common causes for input EOS are hot-plug events and other transient effects involving wire or trace inductance in combination with low ESR ceramic capacitors. Solutions are presented how to avoid EOS via special circuit and system design considerations.
Yes, you read that title correctly. After many months of effort, this homemade-from-scratch electric steam boiler is finally going to make steam. Before we’re done, we’ll learn some sobering lessons about the dangers of live steam.
Now that our boiler is pressure-tested and all the accessories are hooked up, we’re ready to add heat to water and cause some trouble. Unlike a traditional fired boiler which would use fuel pellets, coal, wood, or some other combustible, this crazy contraption is “fired” with an electric immersion heating element built into the structure. In order to test making steam, we need to rig up the electrical bits.
The cheap price however comes with a few niggles, namely getting it up and running in the first place with the limited documentation. Gnarly Grey do a great job of explaining programming a starting program but don’t say much about further development. With that in mind, I’m going to run through the methodology of getting an LED flashing using VHDL. There seem to be a fair few Verilog methods but not many people seem to have touched upon VHDL with these FPGAs.
Another app note from Richtek, this time about transient load testing on power converters and how you can make a simple and low cost fast transient tool. Link here (PDF)
Load transient testing is a quick way to check power converter behavior on several aspects: It will show the converter regulation speed and can highlight loop stability problems. Other power converter aspects like input voltage stability, slope compensation issues and layout problems can be quickly spotted as well. This application note will explain the practical use of load transient testing to diagnose DC/DC power converter problems.
Dr. Scott M. Baker has a nice write-up about a powerful timing node for Node-Red, the Big timer:
Big Timer is (probably) the best-ever timing node for Node-Red, providing a general purpose timer as well as handling summer/winter correctly as well as (importantly) lighting up time (for which you should provide longitude and latitude). After all you probably don’t turn the outside lights on at 6pm!! You turn them on when it gets DARK.
This is a follow-up to our post about using Nokia 5110 screens on three unused analog lines with shift-out. That saved me from messing with the hardware SPI bus which we reserve for the SD cards. A secondary benefit is that the code is really lean, on the order of about 250 bytes for the default font after the compile if you already have EEprom.h in the build anyway. The font, however takes up about 500 bytes, and I wanted the smallest possible footprint so that we could add live data output to loggers that are already compile near the memory limits. As it turns out, stuffing those fonts into the internal EEprom was pretty easy to do:
Using the Arduino’s Internal EEprom to Store Calibration Data & LCD Screen Fonts