ESP32-S3

61 Articles

Toddler Phone Calls Family And No One Else

November 3, 2026 by 12 Comments

The great thing about the modern world is how connected we are. It’s also the worst thing about the modern world, to be honest. [Allan Binder] wanted to give his toddler the very best of that, and escape the worst, with a specially-designed telephone to call Grandma with– and not get scam calls in turn. We’re not going to say his build guide is so thorough a toddler could follow it, but it’s not too far off.

The device is very simple: a commercial ‘retro-style’ handset pairs with an ESP32-S3 over USB. Said ESP32, aside from acting as a USB host, runs a minimal Session Initiation Protocol (SIP) client, which connects via WiFi to a VoIP account the parent has set up. In this case, [Allan] is using Twilio, but there are other internet telephony providers one could use if a Twilio employee once ran over your dog or something.

There are no inbound calls in this setup, so little Timmy isn’t going  to be bothered needlessly about import fees on nonexistent packages or his car’s extended warranty. Dialing out is toddler-friendly, too– it’s as simple as mashing an arcade button linked to the ESP32’s GPIO. Each designated contact gets a button with its pre-programed contact, like the speed dial of yore. A really nice touch is the use of illuminated buttons tied to the time-zone of the designated contact: kiddo will learn quick that if the button isn’t lit, it’s not time for phone calls. The phone will actually say so, via a text-to-speech that also announces network errors and the like.

While cardboard box housing the prototype seems a bit flimsy to trust with any toddler we’ve met, but the concept here is very sound indeed. We’ve seen such kid-communication devices before, but this implementation, aside from being more current, has a lot to recommend it.

Thanks to [Allan Binder] for the tip!

 

Building An ADS-B Receiver For Less Than You Think

November 1, 2026 by 5 Comments

If you’ve ever wondered about the planes flying above your head, you could always listen in to ADS-B transmissions to learn more about them. [thefatmoop] has built a rig to do just that, and it comes in under $50 in parts.

The build is based around the Meshnology W12 board, which combines an ESP32-S3 microcontroller with an LR2021 LoRa Radio. The latter is able to be tuned into transmissions in the realm of 1090 MHz and it can capture ADS-B traffic that uses OOK and Manchester encoding. The data is passed to the ESP32-S3 which validates the CRCs of the captured data and serves up the aircraft tracks on a simple web interface. A GNSS receiver can also be added in so the board knows its own location as well as the location of the planes that it’s tuning in.

[thefatmoop] reports decent performance with the rig, pulling in aircraft tracks from up to 150 nautical miles away using a 915 MHz antenna. There are some mods required to achieve this performance, though—namely, you’ll want to modify the filter configuration on the board to avoid it attenuating the 1090 MHz signals of interest.

There are lots of other ways to listen to ADS-B signals, too—you can always grab yourself an SDR and get going. If you’re cooking up your own cheap radio hacks, don’t hesitate to let us know on the tipsline!

Thanks to [Moser] for the tip!

SIMD-accelerated Machine Vision On An ESP32-S3

October 27, 2026 by 8 Comments

Recently [shraiwi] decided to have a bit of good nerdy fun and implement the FAST machine vision algorithm on an ESP32-S3 using its SIMD ISA. This involves using the assembly instructions for the ISA, making for an exciting opportunity to become familiar with this part of this Xtensa Lx7-based twin-core MCU.

The Features from Accelerated Segment Test (FAST) algorithm is a corner detection method that can determine with reasonable accuracy and in real-time whether a given input frame contains said corners which thus may correspond to objects and other characteristics worthy of note. This is essential for machine vision, with machine learning able to bump up its recognition accuracy even more.

Implementing this algorithm on the ESP32-S3 proved to be a bit of a challenge due to somewhat limited SIMD ISA. Missing instructions included things like comparisons between unsigned byte values, and there is no support for direct misaligned reads.

All of these required some creative coding to work around, but in the end the ESP32-S3 running at 240 MHz was able to process a VGA stream in real-time at 30 FPS. This means about a 2x speed-up over a naive implementation using only non-SIMD instructions.

If you want to play along at home, the Platform IO project is made available on GitHub.

Four black plastic devices, two with a black, stubby antenna, sit on a blue cutting mat with white guidelines. There is also a PCB and a couple grey-ish clips in the assortment. One of the devices is open, showing another PCB with various components including a GPS antenna and LoRa radio. A silhouette of a dog is screen printed next to the text "LIA" on the PCBs, and the same text and image is present in the shell of the device in the top center.

Meshtastic Pet Tracking

October 25, 2026 by 15 Comments

Most commercial pet trackers require a subscription or network connection to function. [Jon G Aguado] wanted a better way and designed LIA, a Meshtastic collar tracker.

LIA uses a custom PCB containing a ESP32-S3, LoRa radio, GPS/GNSS receiver, and a charge controller for the 18650 or 5023450 pouch Li-ion cell powering the device. Everything fits inside a 3D printed enclosure, and the device is charged via a magnetic 4-pin USB pogo connector to increase weather resistance.

One of the neat features of this particular tracker is that [Aguado] gave it two different power modes. High power gets a location fix every 30 seconds and has a pair of bright LEDs for visual assistance, low power only gets a fix every minute or so, and it can also be set to off, which is something we wish more device manufacturers remembered should be an option.

We hope anyone planning on using Meshtastic and LoRa in the US is aware of the issues surrounding FCC compliance, and if you want to track your pet another way, maybe KineFox is an option?

Building An M7 Pan Tilt Head Controller

October 15, 2026 by 11 Comments

The Soonpho M7 Pan Tilt Head is a useful photography tool for remotely aiming a decently-sized camera. Only, [Kyle Housley] wanted a little more control than was available out of the box. Hence, he built a custom controller that could deliver just that.

The project is based around an ESP32-S3 paired with an NRF24L01 wireless module. The ESP32-S3 is hooked up to a computer to receive commands over serial on what movements to make. It then transmits over the NRF24L01 to another NRF24L01 module that has been hacked into the original M7’s controller. In doing so, it can command the M7 to move to a given specific pan and tilt position, or to make a smooth motion along a vector. It can also trigger shutter release in the attached camera as needed, to capture whatever is being looked at.

[Kyle] has used this rig to create a motion tracking system for aircraft photography. With a Yolo vision model running on a laptop, the pan-tilt head can be commanded to track aircraft passing by and photograph them when they’re in frame. It’s a pretty slick setup; we’d love to see similar done with the aid of ADS-B data, too—perhaps even with automatic image tagging and upload.  Continue reading “Building An M7 Pan Tilt Head Controller” →

Tiny E-Paper Display Delivers 30 FPS Of Game Boy Fun

October 14, 2026 by 13 Comments

Slow refresh, ghosting and low-contrast — wait, are we talking about passive matrix LCDs, or e-paper displays? That might be why e-paper Game Boy emulators are a thing: the limitations of the black-on-grey e-paper screens remind us of the grey-on-green LCDs Nintendo used in the 80s. In this case [Bo Made It] made it out of a Waveshare ESP32-S3-ePaper-1.54, and got 30 FPS from it. 

Now, regular readers might be thinking, “So, we’ve seen the 60 FPS e-paper monitor, how is this special?” It’s a fair question. The answer is that [Bo] is doing this on a randomly chosen dev board with a built in wavetable e-paper controller, rather than the bare inputs that allowed the [Wenting Zhang]’s project to work. On the other hand, [Bo] does credit [Wenting], particularly his e-ink PaperBoy project, with directly inspiring both the project and his implementation.

Again, the big difference is going through the blob of the controller, but it turns out you can still address individual pixels through it. [Bo] gave each pixel a ‘budget’ for up to 8 pulses it depending on how much it needs to change, speeding things up immensely. Our favorite part is how he achieves the Game Boy’s 4-bit greyscale by, in effect, deliberately ghosting the display. Pixels aren’t driven long enough to fully flip them if they’re going only one shade lighter or darker. This complicated matters, since going from black to ‘white’ now takes longer than ‘white’ to the next darker grey, and the exact timing needs to be worked out for each color transition. Getting that timing right took a lot of calibration, and we like how he used video to help automate the process.

That process is still ongoing, so there’s no GitHub link yet. [Bo] will open source everything when it’s ready, and we look forward to it. We also look forward to the PDA-like device he’s going to be using this display driver for. If this all sounds similar to a recent 20 FPS e-paper hack, that’s because it’s the same underlying technology.

Continue reading “Tiny E-Paper Display Delivers 30 FPS Of Game Boy Fun” →

The World’s Smallest TV Console Plays DOOM

October 8, 2026 by 15 Comments

We’ve seen plenty of game console projects here, many of them that seek to produce a miniature game console. But this one from [RayTriangle] may break a new barrier entirely — it fits an entire TV game console that plays DOOM, including the battery, into a TV antenna plug.

There’s a type of antenna plug with screw terminals, originally intended for matching 300 ohm balanced feeder to 75 ohm co-ax. It provides a tiny project box if you look at it that way, and it’s in here that the console sits. It’s an ESP32-S3 that talks to a controller via Bluetooth, and he’s gone into some detail on how the RF for the TV is made. Some clever tricks such as a look-up table for the phase shifted chroma waveforms for each color allow the creation of a good quality composite signal through a resistor-ladder DAC, and this is modulated in a surprisingly old-fashioned way onto a carrier provided by the ESP’s clock generator.

The result as can be seen in the video below is a bit noisy, but we think that might be fixable with a little filter magic. It’s designed for PAL TVs with a VHF tuner, but we’re guessing some ingenuity could be brought into play to make it happen for UHF or NTSC. The hardware meanwhile is put on two boards either side of the battery, with a flexible PCB joining the two.

It’s true that gaming though an analogue RF input to a TV is probably less common in 2026, but we applaud the ingenuity in getting this into such a small space. For some reason it reminds us of the world’s smallest MIDI synthesizer.

Continue reading “The World’s Smallest TV Console Plays DOOM“ →