You Can’t Be Too Rich Or Too Thin — A 2mm Thick Computer

We’ve seen credit card-sized computers before, but [Kn/vD] shows us a PIC18-based computer with 9 components that is only 2 mm thick! With 13 K of RAM and 128 K of flash, you can’t do much with it, but a built-in BASIC interpreter can use half the flash like a disk drive and operate with the 20×4 LCD display and the PCB touch-panel keyboard.

The whole thing only has eleven parts, but that’s only because it needed ancillary components like decoupling capacitors and the battery along with a physical reset switch. All the real functions are in the CPU and the LCD display. The schematic is online, but we didn’t see the files for the PCB or the interpreter yet, but it sounds like they are forthcoming. Meanwhile, we wonder if anyone is up to the challenge of going even thinner.

[Kn/Vd] loves small computers. There are plans for a few other versions of the board with AVR and PIC24 processors. The last time we saw a tiny module from [Kn/vD] it ran C. If you check out other Hackaday.io projects on the account, there are several tiny computers there. If you want a business card that can run Linux, you might need to go a little bit thicker.

Two e-readers side to side. On the left, you can see the frontal view, showing text on the e-ink screen. On the right, you can see the backside with a semi-transparent 3D-printed cover over it, and two AAA batteries inside a holder in the center.

Open Book Abridged: OSHW E-Reader Now Simplified, Pico-Driven

If you ever looked for open-source e-readers, you’ve no doubt seen [Joey Castillo]’s Open Book reader, but you might not yet have seen the Abridged version he’s building around a Raspberry Pi Pico.

The Open Book project pairs a 4.2″ E-Ink screen with microprocessors we all know and love, building a hacker-friendly e-reader platform. Two years ago, this project won first place in our Adafruit Feather contest — the Feather footprint making the Open Book compatible with a wide range of MCUs, giving hackers choice on which CPU their hackable e-reader would run. Now, it’s time for a RP2040-based reboot.

three PCBs being shown - one soldered-together version with a Pico on it, and two upopulated PCBs, showing front and back, on the populated PCB, you can see the Raspberry Pi Pico and other components soldered on. On the unpopulated PCBs, you can see there's a lot of text helping you understand and assemble this e-reader.This project is designed so that you can assemble it on your own after sourcing parts and PCBs. To help you in the process, the PCB itself resembles a book page – on the silkscreen, there is explanations of what each component is for, as well as information that would be useful for you while hacking on it, conveying the hardware backstory to the hacker about to dive into assembly with a soldering iron in hand. There’s simple but quite functional software to accompany this hardware, too – and, as fully open-source devices go, any missing features can be added.

Joey has recorded a 30-minute video of the Pi Pico version for us, assembling and testing the newly ordered boards, then showing the software successfully booting and operational. The Pi Pico-based revision has been greatly simplified, with a number of self-assembly aspects improved compared to previous versions – the whole process really does take less than half an hour, and he gets it done with a pretty basic soldering iron, too!

If you’re looking for updates on this revision as development goes on, following [Joey] on Twitter is your best bet. He’s no stranger to making devices around us more free and then sharing the secret sauce with all of us! During the 2021 Remoticon he showed off a drop-in replacement mainboard for the Casio F-91W wristwatch, and told us all about reverse-engineering its controller-less segment LCD — worth a listen for any hacker who’s ever wanted to bend these LCDs to their will.

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

Recycling Junk E-tags Into A LoRaWAN AQI Sensor

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.

Lending A Helping Hand To Hens With AI

As anyone who has taken care of chickens or other poultry before will tell you, it can be backbreaking work. So why not build a robot to do all the hard work for us? That’s precisely what [Aktar Kutluhan] demonstrated with an AI-powered IoT system that automatically feeds chicks and monitors unhatched eggs.

Make no mistake, hens are adorable, feathered creatures, but they can be quite finicky. An egg’s weight, size, and frequency can determine the overall health of a hen, and they can stop laying eggs altogether if something as simple as their feeding schedule is too sporadic. This is precisely what inspired [Aktar] to create a system that can feed hens at a consistent time every day while keeping track of the eggs laid to ensure the coop is happy and healthy.

What’s so impressive about this build isn’t just the clever automation that scratches off a daily chore, it’s built completely with IoT devices, including the AI. The setup uses Edge Impulse as an object detection model on an OPenMV Cam H7 microcontroller to recognize eggs in the coop. From there, an WizFi360-EVB-Pico board was attached so data could be sent over WiFi, with a DHT22 thrown in to monitor and record the overall temperature of the coop.

This is already an amazing setup, but when it comes to IoT devices, the sky’s the limit. You could control heat lamps in larger coops, automatically refill a water bowl if the hens’ water is low, or even build a hands-off incubator.  We’re only just beginning to see the clever ways with which AI can help monitor our pet’s health. Just look at how another hacker used AI to monitor cat poop to make sure their furry friend wasn’t eating plastic. Thanks to [Aktar Kutluhan] for showing us more ways we can use AI to help our pets!

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Simple Stopwatch with two buttons, an eight digit 7-segment display and ICSP programming cable going into the board

Add An OSHW Certified Stopwatch To Your Toolkit

[MakingDevices] has created a simple stopwatch that makes for a nice introduction to surface mount electronic design and assembly. The project is open source hardware (OSHW) certified, with Gerbers, KiCAD files, and software all available.

Conceptually the stopwatch is straight forward, with a row of two four digit seven-segment displays being driven by a PIC18LF14k50 microcontroller through multiple NPN transistors. The PIC doesn’t quite have enough data lines to drive the two displays at once so an inverter is used to toggle between the two seven-segment blocks.

The circuit is continuously powered from a CR2032 coin cell battery. For normal usage with display, [MakingDevices] estimates 30+ hours of operation and 140+ hours without display, but still counting time. When idle, the “Extreme Low-Power (XLP)” capabilities of the PIC put the operating window estimates well beyond the self discharge of the coin cell battery. There’s an in circuit serial programming (ICSP) footprint that accepts a pogo pin TC2030-MCP-NL adapter for flashing the PIC.

Don’t let the simplicity fool you, this is a well documented project with detailed posts about the design, simulation and battery consumption. Various videos and glamour shots give a whole picture of the process, from design, assembly, testing to final validation.

It’d be wonderful to see the project extended or hacked on further, perhaps with a cute enclosure or case.

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For The ESP’s Next ESP Trick…

It is a pretty stale dad joke to tell someone you have ESP when you mean you have an ESP8266 or ESP32 in your hand. However, [Naufil Metkar] uses an ESP device to pretend — via a magic trick — that he does have ESP. The trick requires a bit of 3D printing, an MPU6050 gyro sensor, and a lot of showmanship.

We hate to spoil an illusion, but you can probably figure it out from the list of things you need. The die has a gyro in it and uses a small ESP module to transmit its current orientation out to a display. There is a small reed switch that lets you turn off the device with a magnet. Without it, the battery dies quickly.

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Hackaday Prize 2022: Solar Powered LoRa Weather Station For The Masses

[Debasish Dutta] has designed a few weather stations in the past, and this, the fourth version of the system has had many of the feature requests from past users rolled in. The station is intended to be used with an external weather sensor unit, provided by Sparkfun. This handles wind speed and direction, as well as measuring rainfall. A custom PCB hosts an ESP32-WROOM module and an Ai-Thinker Ra-02 LoRa module for control and connectivity respectively. A PMS5003 sits on the PCB to measure those particulate densities, but most sensors are connected with simple 4-way I2C connectors. Temperature, humidity, and pressure are handled by a BME280 module, UV Index (SI1145), visible light (BH1750) even soil humidity and temperature with a cable-mounted SHT10 module.

All this is powered by a solar panel, which charges a 18650 cell, and keeps the show running during the darker hours. For debugging and deployment, a USB-C power port can also be used to provide charge. A 3D printed Stevenson screen type enclosure allows the air to circulate amongst the PCB-mounted sensor modules, without hopefully too much moisture making it in there to cause mischief.

On the data collection and visualization side, a companion LoRa receiver module is in progress, which is intended to pass along measurements to a variety of services. Think Home Assistant, ESP home, and that kind of thing. Software is still a work in progress, so maybe check back later to see how [Debasish] is getting on with that?

This kind of multi-sensor hosting project is nothing new here, here’s a 2019 Hackaday prize entry along the same lines. Of course, gathering and logging measurement data is only part of the problem, visualization of those measurements is also important. Why not use a mechanical approach, such as a diorama?