ESP32 with multiple DS18B20 temperature sensors


Guide to ESP32 with multiple DS18B20 temperature sensors from Random Nerd Tutorials:

This guide shows how to read temperature from multiple DS18B20 temperature sensors with the ESP32 using Arduino IDE. We’ll show you how to wire the sensors on the same data bus to the ESP32, install the needed libraries, and a sketch example you can use in your own projects. This tutorial is also compatible with the ESP8266 and the Arduino boards.

Teardown of an MVMT dual USB port wall outlet adapter


Kerry Wong did a teardown of an MVMT dual USB port wall outlet adapter:

Specification wise, the adapter is rated to provide 2.1A for its USB output. I did some load testing with an electronic load I built before and it appeared that the 2.1A is rated for the combined output from both USB ports. You can see my testing in the video linked towards the end of this post. This means that if you are charging two devices using this adapter, charging time will be lengthened as the 2.1A output current has to be shared between the two channels.
The internal build quality of this MVMT USB adapter is actually quite good. Two PCBs are used in this adapter. One is for surge protection and the other one is for the switching power supply that generates the 5V output rails.

See the full post on his blog here.

Check out the video after the break.

App note: How to maintain USB signal integrity when adding ESD protection


Introducing the eye diagram method in this app note from ON Semiconductors in determining signal integrity of USB lines. Link here (PDF)

The Universal Serial Bus (USB) has become a popular feature of PCs, cell phones and other electronic devices. USB makes data transfer between electronic devices faster and easier. USB 2.0 transfers data at up to 480 Mbps. At these data rates, any small amount of capacitance added will cause disturbances to the data signals. Designers are left with the challenge of finding ESD protection solutions that can protect these sensitive lines without adding signal degrading capacitance. This document will discuss USB 2.0 and evaluate the importance of low capacitance ESD protection devices with the use of eye diagrams.

App note: Low-side self-protected MOSFET


Integrated fault protected MOSFET app note from ON Semiconductors. Link here (PDF)

The ever increasing density and complexity of automotive and industrial control electronics requires integration of components, wherever possible, so as to conserve space, reduce cost, and improve reliability. Integration of protection features with power switches continues to drive new product development. The often open environments of automotive and industrial electronics, subject to severe voltage transients, high power and high inductance loads, numerous external connections, and human intervention force the requirement of fault protection circuitry. Advancements in power MOSFET processing technology afford an economical marriage of protection features, such as current limitation, and standard MOSFET power transistor switches. This paper describes the technology and operation of ON Semiconductor’s HDPlus monolithic low-side smart MOSFET family.

Building a USB bootloader for an STM32


Kevin Cuzner writes:

As my final installment for the posts about my LED Wristwatch project I wanted to write about the self-programming bootloader I made for an STM32L052 and describe how it works. So far it has shown itself to be fairly robust and I haven’t had to get out my STLink to reprogram the watch for quite some time.
The main object of this bootloader is to facilitate reprogramming of the device without requiring a external programmer.

More details on Projects & Libraries’ homepage.

Building a DIY SMT pick & place machine with OpenPnP


Erich Styger has a nice write-up about building a DIY pick & place machine based on OpenPnP:

This article is about a project I have started back in January 2018. As for many of my projects, it took longer than anticipated.But now it is working, and the result is looking very good: a DIY automated pick and place machine to place parts on circuit boards. In the age of cheap PCBs, that machine closes the gap for small series of boards which have to be populated in a time consuming way otherwise.

See the full post on MCU on Eclipse blog.

Check out the video after the break.


Silicon die analysis: Inside an op amp with interesting “butterfly” transistors


An excellent in-depth look at theTL084 op amp by Ken Shirriff:

Some integrated circuits have very interesting dies under a microscope, like the chip below with designs that look kind of like butterflies. These patterns are special JFET input transistors that improved the chip’s performance. This chip is a Texas Instruments TL084 quad op amp and the symmetry of the four op amps is visible in the photo. (You can also see four big irregular rectangular regions; these are capacitors to stabilize the op amps.) In this article, I describe these components and the other circuitry in the chip and explain how it works. This article also includes an interactive chip explorer that shows each schematic component on the die and explains what it does.

See the full post on Ken Shirriff’s blog.

DIY Arduino FM radio


Nick over at shared detailed instructions of how to build this DIY Art Deco style FM Radio project using Arduino:

Let’s see what we are going to build today! As you can see, we are going to build an Art Deco style FM radio receiver. The design of this radio is based on this spectacular 1935 AWA radio. I discovered this old radio while searching online and also in this book about the most beautiful radios ever made. I loved the design of this radio so much that I wanted to have a similar one. So I devoted a month of my time to build my own.

Full details at

Check out the video after the break.

App note: Capacitive sensing: Direct vs remote liquid-level sensing performance analysis


Capacitive liquid level sensing method comparison discussed in this app note from Texas Instruments. Link here (PDF)

Capacitive-based liquid level sensing is making its way into the consumer, industrial, and automotive markets due to its system sensitivity, flexibility, and low cost. With using TI’s capacitive sensing technology, the system flexibility allows designers to have the choice of placing the sensors directly on the container (direct sensing) or in close proximity to the container (remote sensing). Each configuration has its own advantages and disadvantages. This application note highlights the system differences and performance of direct and remote sensing to provide guidance in how capacitive-based liquid-level sensing is affected.