esp32-C3

17 Articles

Showing a Raspberry Pi 4 board connected to an ESP32 devboard using jumper wires for the purposes of this project

ESP-Hosted Turns ESP32 Into Linux WiFi/BT Adapter

June 25, 2024 by 25 Comments

While we are used to USB WiFi adapters, embedded devices typically use SDIO WiFi cards, and for good reasons – they’re way more low-power, don’t take up a USB port, don’t require a power-sipping USB hub, and the SDIO interface is widely available. However, SDIO cards and modules tend to be obscure and proprietary beyond reason. Enter ESP-Hosted – Espressif’s firmware and driver combination for ESP32 (press release)(GitHub), making your ESP32 into a WiFi module for either your Linux computer (ESP-Hosted-NG) or MCU (ESP-Hosted-FG). In particular, ESP-Hosted-NG his turns your SPI- or SDIO-connected ESP32 (including -S2/S3/C2/C3/C6 into a WiFi card, quite speedy and natively supported by the Linux network stack, as opposed to something like an AT command mode.

We’ve seen this done with ESP8266 before – repurposing an ESP8089 driver from sources found online, making an ESP8266 into a $2 WiFi adapter for something like a Pi. The ESP-Hosted project is Espressif-supported, and it works on the entire ESP32 lineup, through an SDIO or even SPI interface! It supports 802.11b/g/n and even Bluetooth, up to BLE5, either over an extra UART channel or the same SDIO/SPI channel; you can even get BT audio over I2S. If you have an SPI/SDIO port free and an ESP32 module handy, this might just be the perfect WiFi card for your Linux project!

There are some limitations – for instance, you can’t do AP mode in the NG (Linux-compatible) version. Also, part of the firmware has blobs in it, but a lot of the firmware and all of the driver are modifiable in case you need your ESP32 to do even more than Espressif has coded in – this is not fully open-source firmware, but it’s definitely way more than the Broadcom’s proprietary onboard Raspberry Pi WiFi chip. There’s plenty of documentation, and even some fun features like raw transport layer access. Also, of note is that this project supports ESP32-C6, which means you can equip your project with a RISC-V-based WiFi adapter.

Title image from [zhichunlee].

A Telegraph Interface For The Hacker Hotel 2024 Badge

March 30, 2024 by 5 Comments

Hacker Hotel is a small Dutch hacker event that takes place, as its name suggests, in a hotel. It’s a welcome high point in the damp of a north-west-European winter, and attendees come to its setting in the wooded Veluwe region in the centre of the country from far and wide. As is the custom with such events it has an electronic badge, and this year’s one had a rather unusual interface. Instead of a keyboard for text input, it replicates a 19th century Crook and Wheatstone telegraph, replacing the five needles of the original with a diamond-shaped grid of LEDs.

At its heart is an Espressif ESP32-C6 microcontroller which provides both a processor powerhouse and the usual array of wireless connectivity. Paired with that is a much more modest CH32V003 microcontroller to handle I/O tasks, and an e-paper screen using displays salvaged from surplus German supermarket shelf labels. That interface is handled by an array of five-way switches, and in a stroke of genius there’s a small relay on board which does nothing but provide a satisfying tactile “click”. Expansion is seen to by an SAO connector, Qwiic, and a USB-C socket. The software meanwhile is a combination of a non-volatile nametag, a complex set of puzzles used in the on-site competition, and a messaging system using the C6’s 802.15.4 mesh networking. A particularly neat feature of this was a Battleships game that could be played with another badge.

While this isn’t the first Hacker Hotel badge with an e-paper display, we like this one for its novel interface, for the mesh connectivity, and for that clicky relay. We’ll definitely be using ours as a name badge for some time to come.

A DIY handheld PONG game

DIY Pocket PONG Breaks The Mobile Spell

March 18, 2024 by 8 Comments

[Minikk], aka [Athul] is about to enter 10th grade and reports that they and their contemporaries are eschewing boring mobile games for 90s stuff and old games like PONG. Well, we already knew the 90s were back, but it’s nice to see that even older stuff is coming along with it. The kids are alright.

Whether you want to play alone or with a friend, it’s a classic to have in your pocket for sure. The brains behind this 70s-era operation is a Seeed Xiao ESP32-C3, which takes input from the two potentiometers and outputs the game on a 128 x 64 OLED. There’s also a small buzzer for when the ball hits the paddle, or you or your friend slips one past the goalie.

Our favorite part of this build has to be the DIY rivets that hold the OLED in place. [Athul] built posts into the enclosure that get heat-smashed into place with a soldering iron. Pretty neat, huh?

PONG is a specific thrill, certainly. How can it be more thrilling? Maybe with LEDs instead of a screen? Just a thought.

Tiny Motion Detection Alarm Does The Trick

February 24, 2024 by 6 Comments

If you have mischievous children or forgetful elderly in your life, you might want to build a couple of these tiny motion detection alarms to help keep them out of harm’s way. Maybe you want to keep yourself out of the cookie jar. We say good for you.

But you could always put one of these alarms on a window, a drawer, or anything else you don’t want opened or moved. The MPU6050 3-axis IMU makes sure that any way the chosen item gets jostled, that alarm is going off.

As you may have guessed, there isn’t much more to this build — the brain is a Seeed Xiao ESP32-C3, and there’s a buzzer, a battery, a switch, and a push button to program it.

The cool thing about using an ESP32-C3 is that [gokux] can use these for other things, like performing a task when motion is detected. If you do want to build yourself a couple of these, here are step-by-step instructions.

If you’d rather detect motion in the vicinity, here’s a PIR-based solution.

The Egyptian Coin Box ‘Trick’

August 7, 2023 by 9 Comments

[James Stanley] likes to spend time making puzzles and gadgets for escape rooms, and decided for a change to try their hand at a bit of magic. The idea was to construct a ‘magic box’, in which a coin can be placed in one of a number of slots, and then be able to remotely be able to determine the slot by means unseen. Obviously, this is an electronics hack, with a neat package of sensor and radio comms hidden inside a stack of CNC-milled wood. Coin locations are transmitted via Bluetooth to a Bangle.js smartwatch, which vibrates according to the slot occupied, allowing [James] to predict where the coin was placed. Continue reading “The Egyptian Coin Box ‘Trick’” →

Tiny Orrery Keeps The Planets In Their Places

May 9, 2023 by 9 Comments

[Frans] claims to have made the world’s smallest wooden orrery. We won’t take a position on that — such things are best left up to the good folks at Guinness. But given that the whole thing is seriously in danger of being dwarfed by a USB-C connector, we’d say he’s got a pretty good shot at that record.

The key to keeping this planetarium so petite while making it largely out of wood is to eschew the complex gear trains that usually bring the Music of the Spheres to life in such devices. The layered base of the orrery, with pieces cut from a sheet of basswood using a laser cutter, contains a single tiny stepper motor and just two gears. A zodiac disc sits atop the base and is the only driven element in the orrery; every other celestial body moves thanks to a pin set into the zodiac disc. An ESP32 C3 contacts a NASA feed once a day to get the relative positions of the planets and uses the zodiac disk to arrange everything nicely for the day. The video below shows the “Planet Spinner” in action.

We love the look of this project; the burnt edges and lightly smoked surface of the laser-cut wooden parts look fantastic, and the contrast with the brass wires is striking. We’ve seen an orrery or two around here, executed in everything from solid brass to Lego, but this one really tickled our fancy. Continue reading “Tiny Orrery Keeps The Planets In Their Places” →

A Fancy Connected Caliper For Not A Lot

March 11, 2023 by 18 Comments

An essential for the engineer is a decent caliper, to measure dimensions with reasonable accuracy. Some of us have old-fashioned Vernier scales, while many up-to-date versions are electronic. When entering large numbers of dimensions into a CAD package matters can become a little tedious, so the fancier versions have connectivity for automatic reading transfer. [Mew463] didn’t want to shell out the cash for one of those, so modified a cheaper caliper with an ESP32-C3 microcontroller to provide a Bluetooth interface.

Many cheaper calipers have a handy hidden serial port, and it’s to this interface the mod is connected via a simple level shifter. The ESP and associated circuitry is mounted on a custom PCB on the back of the caliper body, with a very neatly designed case also holding a small Li-Po cell. It adds a little bulk to the instrument, but not enough to render it unusable. Whether the work required to design and build it is worth the cost saving over an off-the-shelf connected caliper is left to the reader to decide.

We’ve covered similar hacks in the past, but this one’s to a very high standard. Meanwhile if calipers are of interest to you then they’re a subject we’ve examined in some significant detail.