Tidy POV Display Using The ESP32

November 23, 2022 by Dave Rowntree 9 Comments

Chinese Youtuber [corebb] presents the second version of his POV display. The earlier version used 5050-sized SMT addressable LEDs, which didn’t give great resolution, so he rev’d the design to use a much higher number (160 to be exact) of APA102 LEDs. These are 2mm on the side, making them a little more difficult to handle, so after some initial solder paste wobbles, he decided to use a contract assembly house to do the tricky bit for him. This failed as they didn’t ‘understand’ the part and placed them the wrong way around! Not to be deterred, he had another go with a modified solder stencil, and eventually got the full strip to light up correctly.

Based on an ESP32 (using the Arduino stack) and SDCard for control, and a LiPo cell charged wirelessly, the build is rather tidy. A couple of hall effect switches are mounted at the start of each of the two arms, presumably lining

up with a magnet on the case somewhere, although this isn’t clear. The schematic and PCB appear to have been designed with JLCEDA, which is a repackaging of EasyEDA. We can see the attraction with the heavy integration of this with the JLC and LCSC services. It appears that he even managed to get streamed video working — showing a live video from a webcam — which is quite an undertaking to pull off when you think how much processing needs to happen in real-time. As he alludes to in the video, trying to increase the resolution beyond this point is not viable with the processing capability of the ESP32.

A resin-printed case finishes off the build, with a screw-thread mount added to the rear, to allow typical camera mounts to be used to hold the thing down. A smart move we think.

We love POV displays around here, this spherical POV display is especially fabulous, but you don’t need fancy hardware if you have a handy ceiling fan and a bit of protoboard spare.

Continue reading “Tidy POV Display Using The ESP32” →

Better Air Quality Sensing With CO2

November 21, 2022 by Bryan Cockfield 19 Comments

Measuring air quality, as anyone who has tried to tackle this problem can attest, is not as straightforward as it might seem. Even once the nebulous term “quality” is defined, most sensors use something as a proxy for overall air health. One common method is to use volatile organic compounds (VOCs) as this proxy but as [Larry Bank] found out, using these inside a home with a functional kitchen leads to a lot of inaccurate readings. In the search for a more reliable sensor, he built this project which uses CO2 to help gauge air quality.

Most of the reason that CO2 sensors aren’t used as air quality sensors is cost. They are much more expensive than VOC sensors, but [Larry] recently found one that was more affordable and decided to build this project around it. The prototype used an Arduino communicating over I2C to the sensor and an OLED screen, which he eventually put in a 3D printed case to carry around to sample CO2 concentration in various real-world locations. The final project uses a clever way of interfacing with the e-paper display that we featured earlier.

While CO2 concentration doesn’t tell the full story of air quality in a specific place, it does play a major role. [Larry] found concentrations as high as 3000 ppm in his home, which can cause a drop in cognitive function. He’s made some lifestyle changes as a result which he reports has had a beneficial impact. For human-occupied indoor spaces, CO2 can easily be the main contributor to poor air quality, and we’ve seen at least one other project to address this concern directly.

Wearable Sensor Trained To Count Coughs

November 15, 2022 by Bryan Cockfield 5 Comments

There are plenty of problems that are easy for humans to solve, but are almost impossibly difficult for computers. Even though it seems that with modern computing power being what it is we should be able to solve a lot of these problems, things like identifying objects in images remains fairly difficult. Similarly, identifying specific sounds within audio samples remains problematic, and as [Eivind] found, is holding up a lot of medical research to boot. To solve one specific problem he created a system for counting coughs of medical patients.

This was built with the idea of helping people with chronic obstructive pulmonary disease (COPD). Most of the existing methods for studying the disease and treating patients with it involves manually counting the number of coughs on an audio recording. While there are some software solutions to this problem to save some time, this device seeks to identify coughs in real time as they happen. It does this by training a model using tinyML to identify coughs and reject cough-like sounds. Everything runs on an Arduino Nano with BLE for communication.

While the only data the model has been trained on are sounds from [Eivind], the existing prototypes do seem to show promise. With more sound data this could be a powerful tool for patients with this disease. And, even though this uses machine learning on a small platform, we have seen before that Arudinos are plenty capable of being effective machine learning solutions with the right tools on board.

Screenshot of the Arduino Lab for MicroPython

Arduino Brings A MicroPython IDE

November 14, 2022 by Arya Voronova 52 Comments

Both Arduino and MicroPython are giants when it comes to the electronics education area, and each one of them represents something you can’t pass up on as an educator. Arduino offers you a broad ecosystem of cheap hardware with a beginner-friendly IDE, helped by forum posts explaining every single problem that you could and will stumble upon. MicroPython, on the other hand, offers a powerful programming environment ripe for experimentation, and doesn’t unleash a machine gun fire of triangle brackets if you try to parse JSON slightly incorrectly. They look like a match made in heaven, and today, from heaven descends the Arduino Lab for MicroPython.

This is not an Arduino IDE extension – it’s a separate Arduino IDE-shaped app that does MicroPython editing and uploads code to your board from a friendly environment. It works over a serial port, and as such, the venerable ESP8266-based boards shouldn’t be be left out – it even offers file manager capabilities! Arduino states that this is an experimental effort – it doesn’t yet have syntax checks, for instance, and no promises are made. That said, it already is a wonderful MicroPython IDE for beginner purposes, and absolutely a move in the right direction. Want to try? Download it here, there’s even a Linux build!

High-level languages let you build projects faster – perfect fit for someone getting into microcontrollers. Hopefully, what follows is a MicroPython library manager and repository! We’ve first tried out MicroPython in 2016, and it’s come a long way since then – we’ve seen quite a few beginner-friendly MicroPython intros, from a gaming handheld programming course, to a bipedal robot programming MicroPython exploration. And, of course, you can bring your C libraries with you.

DIY Streamdeck Helps You Professionalize Your Twitch Show

November 12, 2022 by Zoe Skyforest 4 Comments

The one thing that separates the pros on Twitch from the dilettantes is the production values. It’s all about the smooth transitions, and you’ll never catch the big names fiddling with dodgy software mid-stream. The key to achieving this is by having a streamdeck to help control your setup, like this straightforward design from [Electronoobs]. (Video, embedded below.)

The build relies on an Arduino Micro, which is a microcontroller board perfectly equipped to acting as a USB macro keyboard. It’s paired with a Nextion LCD touchscreen that displays buttons for various stream control features, like displaying a “Be Right Back” screen or cuing up video clips. The build also features bigger regular buttons for important quick-access features like muting a mic. It’s all wrapped up in a 3D printed housing, with some addressable RGB LEDs running off another Arduino to add some pizazz. The neat trick is that the build sends keycodes for F13-F24, which allows for the streamdeck’s hotkeys to avoid conflicting with any other software using conventional keyboard hotkeys.

It’s a useful tool that would be of use to anyone streaming on Twitch or other platforms. Alternatively, you could repurpose an old phone to do a similar job. Video after the break.

Continue reading “DIY Streamdeck Helps You Professionalize Your Twitch Show” →

Trigger Your Home Automation Routines With Home Buttons

November 10, 2022 by Dave Rowntree 11 Comments

Home automation systems are all well and good, so long as the person who built it all is around to drive it. Let’s face it, they’re quite often a complex web of interconnected systems, all tied to the specifics of one’s home — and someone less familiar with it all could get a little irritated if, on a chilly day, the interface to the boiler is via a Python script, and something won’t work. Just saying. Home Buttons by [Matej Planinšek] over on Hackaday.IO is a nicely polished project, which aims to take some of the hackiness out of such automation by providing a sleek front end to those automation routines, enabling anyone to rock on over and set one in action without hassle.

The PCB is based around the ESP32-S2-mini which deals with WiFi connectivity and integration with Home Assistant using the usual MQTT protocol. We expect integration with other flavors of home automation would not be difficult to achieve. The center of the unit holds a simple E-Ink display, for that low-standby power. Specifically, the unit chosen is a Good Display GDEY029T94 2.9″ which this scribe can confirm is easy to interface and pretty cheap to purchase from the usual Chinese online vendors. This was matched up with six clicky Alps SKRB-series low-profile tact switches, which sit on either side of the display, and corresponds to a flexure-type affair on the 3D printed front casing. Neat and simple.

The PCB design was provided in Altium format, which you can find on the project GitHub page. This shows a straightforward design, with a few nice little details here and there. The internally mounted 18650 cell is reportedly good for at least a year of operation, but when time, it can be charged via USB. A Xysemi XB8608AF (PDF) protection chip provides appropriate limiting for the 18650 cell, shielding it from the perils of overcharging, discharging, and whatnot. Not that that is likely in this current setup. A Sensiron SHTC3 humidity and temperature sensor is also in there, hanging off the I2C bus, which makes sense for this application.

Home Automation hacks are plenty on these pages, like this scroll-wheel interface, for instance. If all this stuff is looking quite overbearingly complicated to get into, how about starting with a Pico W?

IR Remote tester in use, showing a remote control lighting up an LED and screenshots of the Arduino serial terminal

IR Remote Tester Helps You Crack The Code

November 8, 2022 by Dave Walker 15 Comments

Even though some devices now use WiFi and Bluetooth, so much of our home entertainment equipment still relies on its own proprietary infrared remote control. By and large (when you can find them) they work fine, but what happens when they stop working? First port of call is to change the batteries, of course, but once you’ve tried that what do you do next? [Hulk] has your back with this simple but effective IR Remote Tester / Decoder.

IR remote tester schematic showing arduino, receiver, LED and resistor — How to connect the TSOP4838 to an Arduino to read the transmitted codes

By using a cheap integrated IR receiver/decoder device (the venerable TSOP4838), most of the hard work is done for you! For a quick visual check that your remote is sending codes, it can easily drive a visible LED with just a resistor for a current-limit, and a capacitor to make the flickering easier to see.

For an encore, [Hulk] shows how to connect this up to an Arduino and how to use the “IRremote” library to see the actual data being transmitted when the buttons are pressed.

It’s not much of a leap to imagine what else you might be able to do with this information once you’ve received it – controlling your own projects, cloning the IR remote codes, automating remote control sequences etc..

It’s a great way to make the invisible visible and add some helpful debug information into the mix.

We recently covered a more complex IR cloner, and if you need to put together a truly universal remote control, then this project may be just what you need.

Continue reading “IR Remote Tester Helps You Crack The Code” →