Tutorial, experiment and teardown of a 24GHz Doppler radar module

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Shahriar posted a detailed analysis of a CDM324 24GHz Doppler radar module from IC Station:

Opening the module reveals a series of microwave PCB components and several active devices. A complete analysis of the module is presented. The unit is then measured and the impact of antenna impedance and power supply voltage on the output frequency is measured. The phase noise of the output signal is also measured. Using a series of servo motors, the radiation pattern of the antenna array in both azimuth and elevation is also presented.

More details on The Signal Path blog.

Check out the video after the break.

App note: Designing applications with Lithium-Ion batteries

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More Li-ion battery applications from Richtek. Link here (PDF)

Lithium-Ion batteries have several advantages when compared with other battery types: They are light weight, and energy density of lithium-ion is typically twice that of the standard nickel-cadmium. Li-Ion batteries have no memory effect, and the self-discharge is 6 ~ 8 times less compared to nickel-cadmium. The high cell voltage of 3.6 volts is often sufficient to power applications from a single cell. These properties make Li-Ion batteries very popular in modern portable electronic applications.

App note: Switching battery chargers

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App note from Richtek about several aspects of switching chargers for single cell Li-Ion batteries. Link here (PDF)

Longer battery life and shorter charging times are some of the challenges in battery management in modern hand-held applications like Smart-Phones, Tablet PCs, POS and other portable equipment.

Devices with powerful processors are more power hungry and require larger capacity batteries to guarantee battery life. To quickly charge large capacity batteries, powerful high current chargers are needed. Linear chargers have too limited charge current capability for this purpose, so switching charger topology has to be adopted.

Grbl_ESP32 CNC development board

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Bart Dring has designed a development board for using CNC on Grbl ESP32:

This is a Grbl_ESP32 CNC Development board. This is a quick and easy way to use and test CNC on the ESP32 controller.
Grbl is a great CNC firmware that has been around for nearly a decade. It was originally designed for the Arduino UNO and basic 3 axis CNC routers, but it has been ported to other CPUs and was the basis for many other CNC and 3D printer firmwares.

Project info at Buildlog.Net Blog. It’s also up on Tindie.

Building an Atari Punk console

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Øyvind shows you how to easily make a DIY Atari Punk console:

Do you want a fun and easy-to-build circuit? Here’s the simple, but fun Atari Punk Console – with schematics and parts list. It’s a quick build, so you can easily build it during an evening.
It takes its name from the old Atari computers of the 80s because it makes similar sounds.

More details on Build Electronic Circuits homepage.

Check out the video after the break.

App note: AC ripple current calculations solid tantalum capacitors

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Application note from Vishay on power and voltage limitations of solid tantalum capacitors for both low and high frequency applications. Link here (PDF)

Solid tantalum capacitors are preferred for filtering applications in small power supplies and DC/DC converters in a broad range of military, industrial and commercial systems including computers, telecommunications, instruments and controls and automotive equipment. Solid tantalum capacitors are preferred for their high reliability, long life, extended shelf life, exceptional stability with temperature and their small size. Their voltage range is 4 to 50 volts for the most common types. Tantalum chip capacitors for surface mount applications are manufactured in very small sizes and are compatible with standard pick-and-place equipment.

App note: Electrolytic capacitor lifetime estimation

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Lifetime estimation methods for elcap app note from Jianghai. Link here (PDF)

Aluminum Electrolytic Capacitors (“alu-elcaps”, “elcaps”) are essential for the function of many electronic devices. Ever increasing for enhanced efficiency, the expanding utilization of renewable energy and the continuous growth of electronic content in automotive applications have driven the usage of these components.

In many applications, the lifetime of electronic devices is directly linked to the lifetime of the elcaps inside. To ensure reliable operation of electronic devices for a defined period, a thorough knowledge of the vital properties of elcaps is mandatory.

The present article outlines the construction of elcaps and explains related terms like ESR, ripple current, self-heating, chemical stability, and lifetime. Two estimation tools for obtaining elcap lifetime approximations in an application are introduced and illustrated by an example.

Open source RISC – Eclipse with RISC-V on the SiFive HiFive1 board

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Erich Styger writes:

Open Source software has been around for decades. But open source on hardware especially microcontroller is not much a reality these days. But there is something which might change this: RISC-V is a free and open RISC instruction set architecture and for me it has the potential to replace some of the proprietary architectures currently used. RISC-V is not new, but it gets more and more traction in Academia (no surprise). Not only because it is open: Think about all the recent security issues with proprietary architectures: Spectre, Meltdown, and Foreshadow just be the most recent one.
I wanted to play with RISC-V for over a year, but finally a week ago I did one of these “hey, let’s buy that board” thing again. Sometimes these boards get on a pile to wait a few weeks or longer to get used, but that one I had to try out immediately :-).

More details on MCU on Eclipse site.

Teardown of an MEDA PLM-100 AC Magnetometer

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Kerry Wong did teardown of an MEDA PLM-100 AC magnetometer:

I did a teardown a while ago on a cheap eBay electromagnetic radiation detector, and if you recall the performance of that meter was mediocre at the best. This time around though, I’ve got a MEDA PLM-100 AC magnetometer. Since MEDA (Macintyre Electronic Design Associates) specializes in fluxgate and search coil magnetometers, this PLM-100 magnetometer is a piece of professional test equipment. In this blog post, you will see some teardown pictures and for those who want to see some real world actions you can take a look at the video included towards the end.

See the full post on his blog here.

Check out the video after the break.

App note: Replacing mechanical potentiometers with digital potentiometers

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Another application note from Analog Devices this time about the superiority of digital over mechanical potentionmenters. Link here (PDF)

Potentiometers have been widely used since the early days of electronic circuits, providing a simple way to calibrate a system, adjusting offset voltage or gain in an amplifier, tuning filters, controlling screen brightness, among other uses. Due to their physical construction, mechanical potentiometers have some limitations inherent to their nature, such as size, mechanical wear, wiper contamination, resistance drift, sensitivity to vibration, humidity, and layout inflexibility.

Digital potentiometers are designed to overcome all these problems, offering increased reliability and higher accuracy with smaller voltages glitches. The mechanical potentiometer has now been relegated to environments where the digital potentiometer cannot be a suitable replacement, such as high temperature environments or in high power applications.

Comparing both technologies is the simplest way to discern which is the optimal solution for your system.