In “Eclipse JTAG Debugging the ESP32 with a SEGGER J-Link” I used a SEGGER J-Link to debug an ESP32 device with JTAG. I looked at using one of the FTDI FT2232HL development boards which are supported by OpenOCD. The FT2232HL is dual high-speed USB to UART/FIFO device, and similar FTDI devices are used on many boards as UART to USB converters. With OpenOCD these devices can be turned into inexpensive JTAG debug probes. This article shows how to use a $10 FTDI board as JTAG interface to program and debug the Espressif ESP32.
Designing a custom lithium battery pack is a fun way to learn about electricity and engineering. Lithium batteries can be used for countless applications including electric bikes, scooters, vehicles, backup power suppliers, off the grid solutions, and much more.
The current Espressif documentation integrating with Eclipse are kind of broken and did not work for me (they are changing from make files to use CMake). The good news is that I have found a way to easily integrate the IDF with Eclipse which is documented below. Because I’m using the ESP32 in combination with the NXP Kinetis and SDK, it makes sense to have everything in the MCUXpresso IDE (I’m using the Version 11.0.0).
This tutorial is a step-by-step guide that shows how to build a standalone ESP8266 Web Server that controls two outputs (two LEDs). This ESP8266 NodeMCU Web Server is mobile responsive and it can be accessed with any device with a browser in your local network.
Shawon Shahryiar over at Embedded Lab shared a how-to on making a SPL dB meter:
Sound needs a medium for propagation or travel. It can’t travel in vacuum. Normally air is that medium but sound can also propagate in liquids and other states of matter. I am not going to lecture on how sound travels and its properties as Wikipedia details everything well here. Everything we see around us has a measurement and a unit. In case of sound pressure, the unit is decibel. Our basic requirement is to be able to measure Sound Pressure Level (SPL) in decibel scale with a typical 8-bit microcontroller, an ordinary microphone and without involving complex algorithms.
Measurement of sound has a number of uses. For instance, monitoring sound pollution, security system, monitoring the quality of an amplifier, detecting sound profile of an environment, etc.
Here, I will show how you can make your own version of the 555 timer using just NAND gates, opamps , a transistor and a few resistors! Now, you may think what is the purpose of building this when you can buy the IC at very cheap rates. The answer is, you learn electronics better, understand how the actual IC functions and improve your confidence in building electronic circuits.
This build combines small dozens of small laser-cut acrylic pieces which fit together with very tight tolerances. It uses skinny (4mm wide) LED strips which must be soldered, bent, and then slotted in between those acrylic pieces. When assembling the parts you must be willing to force pieces into place, even though it feels like you are stressing the brittle acrylic. You must also be willing to remove and re-seat said pieces and LED strips when it turns out they *can’t* actually be forced into place. At some point during the assembly there is a strong likelihood that you will have to remove everything and re-solder your LED strip when you realize that forcing everything into place broke one of the wires away from your LED strip or created a short circuit.
Johnson Davies shared detailed instructions of how to build an ATSAMD21-based computer on a prototyping board using a 32-pin ATSAMD21E:
If you’re looking for something more powerful than the ATmega328 in the Arduino Uno a good choice is the ATSAMD21. This is an ARM Cortex M0+ processor with up to 256KB flash memory, 32KB RAM, and a 48MHz clock, so it’s substantially better equipped than the ATmega328. In addition it has a USB interface built in, so there’s no need for a separate chip to interface to the serial port.
Arduino have designed several excellent boards based on the ATSAMD21, such as the Arduino Zero or smaller-format MKRZERO. However, these boards are an expensive way to use an ATSAMD21 as the basis for your own project, and they probably include many features you don’t need.