To make my ESP32 ZX Spectrum touch keyboard work even better, I needed to ensure every key was independent. The ESP32-S3 only has 14 touch pins, so I’ve been using a matrix approach. While this works well, it struggles with key combinations, critical for the ZX Spectrum. I explored touch detection and experimented with analog multiplexer ICs (4051 series) to expand the touch pins. Initial tests were promising. After prototyping with breadboard-friendly versions and ordering parts, the new keyboard was not only functional but exceeded my expectations. Scanning the keyboard now takes around 20ms, and the solution is ready for...
In a bid to quench my nostalgia and flex my ESP32 chops, I managed to get a ZX Spectrum emulator running on my ESP32-TV board! Then, spurred on by PCBWay's new full color silk screen service, I pursuit the audacious task of recreating the ZX Spectrum's iconic keyboard. It's been quite the joyride - wrangling touch pins, shrinking screens and creating a thing of beauty on PCB. It's not quite ready for the spotlight, but keep an eye on my newsletter for more eagerly-awaited updates. It's like the Spectrum is reborn!
In the latest board revision, I've successfully resolved some key issues, including a USB interface conflict between the USB2244 and the ESP32 and a risky battery charging mistake—no more direct USB 5V to the battery! Plus, I managed to wrap this up without any clumsy bodge wiring. I've even introduced a new feature: a microphone is now on board, setting the stage for some exciting future projects. Stay tuned for what's coming!
Dove into hacking an LED curtain and discovered that despite lacking visible daisy chaining, it's hackable! With LEDs pre-programmed for their position, it can receive collective data and recognize individual signals. Flashed WLED firmware onto an ESP32 and, voila, it lit up beautifully, even supporting 2D grid patterns for cool visuals. The key components: a BLE SoC, buffer IC for level shifting, and a curious way of LED data handling that's cleverly efficient.
Just received the new PCBs for the ESP32-TV project and they're looking sharp with only a tiny resistor tweak needed. But I discovered a sneaky, undocumented resistor causing a conflict between the ESP32 and USB2244 over the USB connection. Fixed that, but there's a bigger issue lurking in the design - check the schematic in the video and see if you can spot it before I reveal the explosive mistake!
After lots of tinkering, I've managed to improve the speed of writing to the SD Card of my ESP32-TV considerably, but it's still not as fast as I'd like. The Arduino 'readRaw' and 'writeRaw' functions were the culprits, they can only write one sector at a time! After bypassing this and using IDF functions, writing speed improved by 70%. I also experimented with writing to the SD Card in the background, which ironically yielded even better results. However, it's still slower than I'd like, so I've got a crazy new plan: using a cheap IC (GL823) for SD card interfacing...
An intriguing issue appeared in the esp32-tv project that deals with speeding up JPEG file decoding using SIMD (Single Instruction Multiple Data) instructions, showing immense performance boost. However, there were some notable differences in speed when it comes to drawing the images versus simply decoding them. The problem was found to be with the DMA drawing mechanism and the way the new fast library decodes the image all at once. But despite this hiccup, by overlapped decoding and displaying process, a high frame rate can still be achieved. Joined me in this dissecting process and my initial tests showing approximately...
After some quality time with my ESP32 microcontroller, I've developed a version of the TinyTV and learned a lot about video and audio streaming along the way. Using Python and Wi-Fi technology, I was able to set up the streaming server with audio data, video frames, and metadata. I've can also explored the picture quality challenges of uncompressed image data and learned about MJPEG frames. Together with JPEGDEC for depth decoding, I've managed to effectively use ESP32's dual cores to achieve an inspiring 28 frames per second. Discussing audio sync, storage options and the intricacies of container file formats for...
In a thrilling DIY endeavour, I attempted to build the most minimalist ESP32 dev board possible. Diving deep into the schematic of the ESP32 S3 WROOM module, I chopped out the non-essentials and whittled our needs down to bare bones. The experiment saw me juggling USB data lines and voltage regulators, waving goodbye to an array of capacitors and connectors and boldly embracing the simplicity of direct connections. Despite a few hitches, the miniature Frankenboard came alive, proving that sometimes less is more...at least in the world of microcontrollers.
After a previous unsuccessful attempt to power my Christmas lights with solar power, I've decided to try run my ultra-energy efficient ePaper weather display on solar energy. This display, already low on power consumption thanks to ESP32's deep sleep mode, is now paired with the BQ25570 energy-harvesting board and lithium cell to test if solar power can keep it running. Despite the limited Scottish winter sun, initial results look promising. With a little more code tinkering, it is my belief that the weather display might just keep running indefinitely and never need charging again.
After some stress and trepidation, I finally took the plunge and sent my PCB design off for manufacturing. My design centers around building a large seven-segment clock with LED filaments. Jumping hurdles such as voltages, pin usage, and limiting the load on my power supply, I've settled on the ESP32 as the system's heart and come up with a final circuit design. While doing this, I've quickly realized I could improve my layout and fixed a small mistake. Also, I've prepared for either types of LED filaments - the high-voltage ones or the larger, 3v ones. However, I did bungle...
In this blog post, we delve deep into the intriguing concepts of I2S audio and DMA, particularly focusing on parameters like dma_buf_count and dma_buf_len. We explore their roles, ideal values, and the impacts they have on aspects such as CPU load and latency. We also discuss the limitations that come hand in hand with these parameters. This post aims to provide you some insights on trading-off between latency, CPU load, memory usage and the overall buffer space allocation. However, the primary takeaway remains that the optimal configurations largely depend on individual context and application needs.
This post provides a comprehensive guide to building a do-it-yourself (DIY) Alexa using an ESP32 and Wit.ai. It illustrates how to create a wake word detection system, use Python for machine learning and employ TensorFlow for the 'wake' word identification. It also covers the usage of Wit.ai for intent recognition and managing commands. The post is fully backed with code snippets, examples and video tutorials to deliver an interactive learning experience to readers.
In this blog post, I've delved deep into the world of audio input for ESP32, exploring all the different options for getting analogue audio data into the device. After discussing the use of the built-in Analogue to Digital Converts (ADCs), I2S to read ADCs with DMA, and using I2S to read directly from compatible peripherals, I go on to present hands-on experiments with four different microphones (MAX4466, MAX9814, SPH0645, INPM441). This comprehensive look at getting audio into the ESP32 should be a valuable resource for anyone hungry for a deep-dive into ESP32's audio capabilities, complete with YouTube videos for an...
I've successfully used addressable WS2811 LED strings and an ESP-CAM board to create an adjustable lighting system. The best part is that the image processing code can be duplicated in JavaScript which allows you to use a plain dev board to drive the LEDs instead of needing a camera on your ESP32 board. If you want to replicate this project, you'll need your own ESP32 dev board and some addressable LEDs. After figuring out the location of each LED in 2D space, it's easy to map from each LED's x and y location onto a pattern you want to show...