e-paper display showing hand-drawn fonts attached to a custom controller PCB

Recycling Junk E-tags Into A LoRaWAN AQI Sensor

September 28, 2022 by Dave Rowntree 6 Comments

E-paper interfacing circuit is just a simple switched-mode power supply — Interfacing to E-paper displays is nothing to be scared of

[Aduecho] had seen those cheap eBay deals of e-paper-based pricing tags, and was wondering if they could be hacked to perform some other tasks. After splitting the case open, the controller chip was discovered to be a SEM9110, with some NFC hardware support but little else. [aduecho] was hoping to build some IoT-connected air quality indicator (AQI) units but the lack of a datasheet for SEM9110 plus no sensors in place meant the only real course of action was to junk the PCB and just keep the E-paper display and the batteries. These units appeared to be ‘new old’ stock, so there was a good chance that both would be fresh and ripe for picking.

The PCB [aduecho] came up with is mechanically the same as the original unit, but now sports a Seeed studio Wio-E5 LoRa module, which uses the STM32WLE5 from ST for the heavy lifting. This has what looks like a Semtech SX126x integrated on-die (we can’t think of a sane way an actual SX126x die could be flip-chip mounted, but you never know). Using this module is a snap, needing only very minimal antenna-matching components and a spot of decoupling to function. On the sensing side of things, a Bosch BME680 gas sensor handling the AQI measurements, and a Bosch BMI270 6-axis IMU, provides a gyro and accelerometer, for all those planned user interaction features. As can be seen from the schematic, interfacing the EPD is pretty straightforward, just a handful of parts are needed to generate the necessary bipolar gate voltages via a simple SMPS circuit. The display controller handles it all internally, programmed via an SPI interface.

One area we’re quite fond of in this project are the neat hand-drawn icons, and variable width font, giving the display a kind of note-like quality when drawn on the low-ish contrast e-paper display.

Air quality measurement projects grace these pages from time to time, like this hacked Ikea Vindriktning, and this very similar Wio-E5-based project we covered last month.

LoRa Air Quality Monitor Raises The Bar On DIY IoT

August 30, 2022 by Tom Nardi 15 Comments

We’ve seen an incredible number of homebrew environmental monitors here at Hackaday, and on the whole, they tend to follow a pretty predicable pattern. An ESP8266 gets paired with a common temperature and humidity sensor, perhaps a custom PCB gets invited to the party, and the end result are some values getting pushed out via MQTT. It’s a great weekend project to get your feet wet, but not exactly groundbreaking in 2022.

Which is why we find the AERQ project from [Mircea-Iuliu Micle] so refreshing. Not only does this gadget pick up temperature and humidity as you’d expect, but its Bosch BME688 sensor can also sniff out volatile organic compounds (VOCs) and gases such as carbon monoxide and hydrogen. The datasheet actually claims this is the “first gas sensor with Artificial Intelligence (AI)”, and while we’re not sure what exactly that means in this context, it’s a claim that apparently warrants a price tag of $15+ USD a pop in single quantities.

There’s an AI hiding in there someplace.

But the fancy sensor isn’t the only thing that sets AERQ apart from the competition. Instead of a member of the ubiquitous ESP family, it’s using the Wio-E5, a relatively exotic STM32 package that integrates a long-range LoRa radio. [Mircea-Iuliu] has paired that with a Linx USP-410 chip antenna or, depending on which version of the four-layer PCB you want to use, a u.Fl connector for an external antenna. The whole thing is powered by a simple USB connection, and its Mbed OS firmware is setup to dump all of its collected data onto The Things Network.

All told, it’s a very professional build that certainly wouldn’t look out of place if it was nestled into some off-the-shelf air quality monitor. While the high-end detection capabilities might be a bit overkill for home use, [Mircea-Iuliu Micle] points out that AERQ might provide useful insight for those running indoor events as COVID-19 transitions into its endemic stage.

A Merciless Environmental Monitoring System

August 10, 2022 by Tom Nardi 12 Comments

We’ve seen plenty of environmental monitoring setups here on Hackaday — wireless sensors dotted around the house, all uploading their temperature and humidity data to a central server hidden away in some closet. The system put together by [Andy] from Workshopshed is much the same, except this time the server has been designed to be as bright and bold as possible.

The use of Mosquitto, InfluxDB, Node Red, and Grafana (M.I.N.G) made [Andy] think of Ming the Merciless from Flash Gordon, which in turn inspired the enclosure that holds the Raspberry Pi, hard drive, and power supply. Some 3D printed details help sell the look, and painted metal mesh panels make sure there’s plenty of airflow.

While the server is certainly eye-catching, the sensors themselves are also worth a close look. You might expect the sensors to be based on some member of the ESP family, but in this case, [Andy] has opted to go with the Raspberry Pi Pico. As this project pre-dates the release of the wireless variant of the board, he had to add on an ESP-01 for communications as well as the DTH11 temperature and humidity sensor.

For power each sensor includes a 1200 mAh pouch cell and a Pimoroni LiPo SHIM, though he does note working with the Pico’s energy saving modes posed something of a challenge. A perfboard holds all the components together, and the whole thing fits into an understated 3D printed enclosure.

Should you go the ESP8266/ESP32 route for your wireless sensors, we’ve seen some pretty tidy packages that are worth checking out. Or if you’d rather use something off-the-shelf, we’re big fans of the custom firmware developed for Xiaomi Bluetooth thermometers.

Continue reading “A Merciless Environmental Monitoring System” →

Jigglypuff Sensor Breathes CO2 So You Don’t Have To

November 16, 2021 by Tom Nardi 3 Comments

We’ve seen a lot of environmental monitoring projects here at Hackaday. Seriously, a lot. They usually take the form of a microcontroller, a couple sensors, and maybe a 3D printed case to keep it all protected. They’re pretty similar functionally as well, with the only variation usually coming in the protocol used to communicate their bits of collected data.

But even when compared with such an extensive body of previous work, this Jigglypuff IoT environmental monitor created by [Kutluhan Aktar] is pretty unusual. Sure, the highlights are familiar. Its MH-Z14A NDIR CO2 sensor and GP2Y1010AU0F optical dust detector are read by a WiFi-enabled microcontroller, this time the Arduino Nano RP2040 Connect, which ultimately reports its findings to the user via Telegram bot. There’s even a common SSD1306 OLED display on the unit to show the data locally. All things we’ve seen in some form or another in the past.

Testing the electronics on a bread board.

So what’s different? Well, it’s all been mounted to a huge Pokémon PCB, obviously. Even if you aren’t a fan of the pocket monsters, you’ve got to appreciate that bright pink solder mask. Honestly, the whole presentation is a great example of the sort of PCB artwork we rarely see outside of the BadgeLife scene.

Admittedly, there’s a lot easier ways to get notified about the air quality inside your house. We’re also not saying that haphazardly mounting your electronics onto a PCB designed to look like a character from a nearly 20+ year old Game Boy game is necessarily a great idea from a reliability standpoint. But if you were going to do something like that, then this project is certainly the one to beat.

NRF52 Weather Station Gives Forecast With Style

March 11, 2021 by Tom Nardi 9 Comments

We’re no strangers to DIY environmental monitors around these parts, in fact, it seems like that’s one of the most common projects hackers take on when confronted with the power of a modern Internet-connected microcontroller. But among such projects, this miniature nRF52-based weather station built by [Andrew Lamchenko] is among the most polished we’ve seen.

Externally, this looks as though it could easily be a commercial product. The graphical interface on the ePaper display is very well designed, delivering plenty of data while still looking attractive enough to hang in the kitchen. The enclosure is 3D printed, but [Andrew] poured enough elbow grease into sanding and polishing the front that you might not realize it at first glance.

Internally it uses the popular BME280 sensor to detect temperature, humidity, and barometric pressure, though the custom PCB is also compatible with the similar SI7021 and HTU21D sensors if you want to switch things up.

That said, you really want the ability to measure pressure, as it allows the firmware to do its own basic weather forecasting. All the collected data is beamed out over Bluetooth Low Energy (BLE), where it can be collected by the open source MySensors IoT framework, but we imagine it wouldn’t take much work to integrate it into your home automation system of choice.

As excited as we might be about the prospect of repurposing things such as electronic shelf labels, we’re happy to see the prices for general purpose electronic paper screens finally dropping to the point where projects of this caliber are within the means of the hacker crowd.

Continue reading “NRF52 Weather Station Gives Forecast With Style” →

Custom Weather Camera Feed With Software Tricks

July 23, 2020 by Tom Nardi 4 Comments

With a gorgeous view of the Italian seaside, we’re not surprised [Danilo Larizza] had a couple IP cameras set up to pull in real-time views. But using a Raspberry Pi, an environmental sensor, and some software trickery to overlay the current (and naturally, perfect) weather conditions over the images? Now he’s just teasing us.

Whatever his motives are, we have to admit that the end result is very nice. Especially when you find out that there’s no complex hardware or software at work here. An original Raspberry Pi is doing all the heavy lifting by pulling a frame from the external IP camera using ffmpeg, polling the I2C-connected BME280 temperature and humidity sensor with a Python script, and then producing a final snapshot with the environmental data laid over top using ImageMagick.

[Danilo] gives the exact commands he’s using for each step of the process, making it easy to follow along and see how everything comes together in the end. That also makes it much easier to adapt for your own purposes should you feel so inclined. Once you see how all the pieces fit together, where the data and images come from is up to you.

We’ve previously shown how some simple Python code can be used to turn your raw data into attractive images, and combining that with real-world photographs is an excellent way of turning a text file full of values into a display worth showing off.

A Slightly Bent ESP8266 Sensor Platform

January 14, 2020 by Tom Nardi 14 Comments

The ability to get professionally manufactured PCBs, at least small ones, for dirt cheap has had a huge impact on the sort of projects we see around these parts. It’s getting to the point where experimenting with PCB enclosures is not only a way to make your next project stand out, but an economical choice.

Which is how this ESP8266 sensor gadget from [Josef Adamčík] got its unique “folded over” look. The top panel is where the microcontroller and headers for various sensors live, the bottom panel is home to the TP4056 USB charging module, and the center panel provides mechanical support as well as holds the single 18650 cell. Rather than close the whole thing up with a fourth panel, he decided to leave it open so the battery can easily be removed. Plus, of course, it looks cooler this way.

Could [Josef] have fit all his electronics on a single 100 x 100 PCB and then put the whole thing into a 3D printed enclosure? Well, sure. But that’s been done to death at this point, and besides, he was looking for an excuse to get more comfortable doing PCB design. We think it also makes for a considerably more visual appealing final product than simply taking the “normal” way out.

Currently [Josef] has an SHT21 humidity/temperature sensor and a BH1750 light sensor slotted into the headers on the top side of the device, but they could just as easily be swapped out with something else if you wanted to do something a bit more exciting. We notice that homebrew air quality monitors are becoming increasingly popular.

Building bespoke enclosures from PCBs is a fantastic trick that frankly we’d love to see more of. It’s somewhat of an artform in itself, but if you’re willing to put the effort in to do it right the results can be truly phenomenal.