From the great minds behind the NodeMCU Lua interpreter for the ESP8266 comes a proper dev board for the WiFi platform of 2015. They are calling it, the NodeMCU-devkit, and it’s a reasonable, cheap, and breadboardable breakout board for the ESP8266.
The version of ESP8266 used in this project is the ESP-12, the newer, fancier model with RF shielding, a questionable FCC logo, and every single one of the GPIOs exposed on castellated connectors. The rest of the board is a USB to serial converter (the CH340G – probably the cheapest USB to serial chip out there), a few passives, and a USB micro connector. It’s simple, cheap, and open source. You can’t do better than that.
This dev board is explicitly designed to work with the NodeMCU firmware, a Lua-based firmware for the ESP. Already we’ve seen some projects make the Hackaday front page with this firmware. Sure, it’s just a garage door opener, but that’s extremely impressive for a chip that’s only a few months old.
Thanks [Baboon] for the tip.
It seems like just yesterday (maybe for some of you it was) we were installing Windows 3.1 off floppy drives onto a 256 MB hard drive, but hard drives have since gotten a lot bigger and a lot more complicated, and there are a lot more options than spinning platters.
The explosion of storage options is the result of addressing a variety of niches of use. The typical torrenter downloads a file, which is written once but read many times. For some people a drive is used as a backup that’s stored elsewhere and left unpowered. For others it is a server frequently reading and writing data like logs or swap files. In all cases it’s physics that sets the limits of what storage media can do; if you choose wisely for your use case you’ll get the bet performance.
The jargon in this realm is daunting: superparamagnetic limit, LMR, PMR, CMR, SMR, HAMR, MAMR, EAMR, XAMR, and QLC to name the most common. Let’s take a look at how we got here, and how the past and present of persistent storage have expanded what the word hard drive actually means and what is found under the hood.
Continue reading “Bespoke Storage Technologies: The Alphabet Soup Found In Modern Hard Drives And Beyond”
It should be no surprise to many that one can use a Raspbery Pi SBC as an industrial controller, but is it any good at that? That was the question which [Dough Reneker] and [William Shaffer] built a test rig to see how a Raspberry Pi performs in head to head tests. They compared a Python-based control loop on a Raspberry Pi 3B against an C0-12DD1E-2-D AutomationDirect CLICK Programmable Logic Controller (PLC) using a simple water heating example.
A major snag with using the Raspberry Pi as a PLC is the lack of industrial I/O capacity. This requires additional hardware, in this case adding a four-channel ADC board as well as a custom board to condition the signals. The Raspberry Pi looks for 0-3 V inputs where industrial control applications are usually in the -10 to 10 V range and often use a 4-20 mA current loop.
Using a PLC leverages so-called ladder logic, where each action depends on conditions. With each update scan, the PLC ensures that all input conditions are translated into the appropriate output conditions in real-time. It’s only job is to monitor the process at hand and it does this very well.
Here the flexibility and generic nature of the Raspberry Pi running Linux was a disadvantage. Unlike the PLC, the lack of a hard real-time OS means you can’t guarantee the Pi will be as responsive to changing inputs.
The behavior of the two systems showed that while both did the task they were programmed for, the Raspberry Pi was decidedly more erratic. Although one could program around a lot of these issues (presumably using Linux in stripped-down, soft real-time configuration with interrupt-driven native code), the effort needed to make a Raspberry Pi system suitable for an industrial environment shows why single-board computers haven’t seen adoption as replacements for PLCs.
Continue reading “Evaluating Raspberry Pi As A Programmable Logic Controller”
When you are ready to design real things, you’ll find simple CAD programs can be pretty limiting. Serious modern designs tend to use parametric modeling where you don’t necessarily set dimensions and positions of everything but instead constrain the design by describing the relationship between different elements. For example, you can create a vertical line and constrain other lines to be parallel, perpendicular, or form a given angle with that line. There are many tools that can do that, including FreeCAD and SolveSpace, two programs that [Joko Engineeringhelp] uses to create a complex compressor blade and it really shows the differences and similarities between the two tools.
You probably don’t need this particular design, but watching over someone’s shoulder while they do a complex design can be very valuable. Being able to see the differences between the two tools might convince you to learn one or the other or maybe even switch.
Continue reading “FreeCAD Vs SolveSpace”
Some hacks are born of genius or necessity, and others from our sheer ham-fisted incompetence. This is not a story about the first kind. But it did give me an excuse to show how easy it is to design WiFi-connected devices that work the way you want them to, rather than the way the manufacturer had in mind.
It started out as a sensible idea – consumer electronics in Vietnam have many different electric plug types for mains AC power: A, C, G, F, and I are fairly present, with A and C being most common. For a quick review of what all those look like, this website sums it up nicely. There are universal power adapters available of course, but they tend to fit my most common type (C) poorly, resulting in intermittent power loss whenever you sneeze. So I figured I should replace all the plugs on my devices to be A-type (common to those of you in North America), as it holds well in all the power bar types I have, mainly leftover server PDUs.
This was very straightforward until I got to my desk lamp. Being a fancy Xiaomi smart lamp, they had opted to hide a transformer in the plug with such small dimensions that I failed to notice it. So instead of receiving a balmy 12 volts DC, it received 220 volts AC. With a bright flash and bang, it illuminated my desk one final time.
Continue reading “Fried Desk Lamp Reborn: How To Use ESP8266 To Build Connected Devices”
The ESP8266 is a great processor for a lot of projects needing a small microcontroller and Wi-Fi, all for a reasonable price and in some pretty small form factors. [Simon] used one to build a garage door opener. This project isn’t really about his garage door opener based on a cheap WiFi-enabled chip, though. It’s about the four year process he went through to learn how to develop on these chips, and luckily he wrote a guide that anyone can use so that we don’t make the same mistakes he did.
The guide starts by suggesting which specific products are the easiest to use, and then moves on to some “best practices” for using these devices (with which we can’t argue much), before going through some example code. The most valuable parts of this guide especially for anyone starting out with these chips are the section which details how to get the web server up and running, and the best practices for developing HTML code for the tiny device (hint: develop somewhere else).
[Simon] also makes extensive use of the Chrome developers tools when building the HTML for the ESP. This is a handy trick even outside of ESP8266 development which might be useful for other tasks as well. Even though most of the guide won’t be new to anyone with experience with these boards, there are a few gems within it like this one that might help in other unrelated projects. It’s a good read and goes into a lot of detail about more than just the ESP chips. If you just want to open your garage door, though, you have lots of options.
[Zack] had trouble getting his six-month-old to sleep through the night. That was before he found out about ‘shh’ videos on YouTube. These are exactly what they sound like: eight hours of someone whooshing white noise into a microphone. He set a phone up on a charger in the nursery and let one of these play overnight. But the phone was unreliable. It would lock up, or just crash completely, making the baby’s distress worse.
To restore peace in the house, he built a sound machine that both simplifies and fortifies the white noise shh-loution. It uses an ESP8266 and a DFPlayer Mini to loop a lone MP3 file of shh-video audio and play it from a small speaker. By integrating the machine with Home Assistant, he’s able to trigger the sound remotely at baby’s bedtime. ESP Home has no module for the DFPlayer, but [Zack] built one that he’s happy to share.
If you are mired in early parenthood, this is a nice, simple solution. The DFPlayer does all the work of reading from the SD card and converting the signal to analog for speaker output, so there’s no need to get your hands dirty wasting valuable sleeping or kid-playing time.
Once the kid starts toddling out of babyhood, [Zack] could turn to ESP8266-based ambient lighting to help establish the difference between sleep and wake time.