App note: Thermal mass flow sensors for gas and liquid applications

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White paper from Integrated Device Technology on the emergence of MEMS thermal mass flow sensors. Link here (PDF)

Flow meters represent the instrumentation of flow sensors and are used to measure the amount of flow that passes through them. There are in principal five different flow meter types: velocity flow, positive displacement flow, differential pressure flow, open channel flow, and mass flow. Mass flow meters are one of the dominant types in the market due to their faster response and better accuracy than other flow meters. They can also be effectively miniaturized and manufactured on silicon wafers. The emergence of MEMS has already revolutionized the consumer electronics market for motion, pressure, and other sensors, and similar micro-machining processes are now being adapted to fabricate flow sensors. Flow sensing applications are typically high-mix and low-to-medium volume compared, for example, to motion sensors that have become ubiquitous in hundreds of millions of smartphones. This paper will focus on the emergence of thermally-based MEMS mass flow sensors and how they match up with existing and more traditional flow sensor technologies.

App note: Ferrite bead demystified

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App note from Analog Devices hinting for proper selection of ferrite bead for you applications. Link here (PDF)

An effective method for filtering high frequency power supply noise and cleanly sharing similar supply rails is the use of ferrite beads. A ferrite bead is a passive device that filters high frequency noise energy over a broad frequency range. It becomes resistive over its intended frequency range and dissipates the noise energy in the form of heat. The ferrite bead is connected in series with the power supply rail and is often combined with capacitors to ground on either side of the bead. This forms a low-pass filter network, further reducing the high frequency power supply noise.

Building and Flashing ESP32 applications with Eclipse

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Erich Styger shared the steps how to use Eclipse with CMake:

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).

See the full post on MCU on Eclipse blog.

The Script

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Peter Scargill’s Script:

Regular readers will know about the script that Aidan Ruff and I originally developed to put Node-Red and several other packages onto the Raspberry Pi for our own home control purposes. This has been developed with help from several people and in particular my friend Antonio “Mr Shark”.
WELL – here is the script which is intended to help set-up certain Raspbian, Debian or similarly-based SBCs which now includes logging and handling Raspbian Buster (tested on Raspberry Pi 2, 3, 3B+, 4 with Stretch, 3B+ and 4 with Buster). As well as it’s original purpose of setting up a Raspberry Pi, the script also runs well with several other boards. See right hand side of the above image for what the script does, given a basic operating system install. We currently suggest NOT using this with DIET PI, original Pi or the Raspberry Pi Zero as we are no longer testing either and the latter pair are just TOO SLOW.

See the full post on Scargill’s Tech Blog.

Check out the video after the break.

tinyOSD & tinyFINITY – a tiny opensource video tx with full graphic OSD

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tinyOSD and the tinyFINITY,  a tiny open source video transmitter with integrated graphic OSD from fishpepper.de

As I like fully integrated solutions I started to work on a new PCB design that includes a RTC6705 video transmitter and my tinyOSD into one tiny 16x16mm board called tinyFINITY. The image shows a preliminary version where I tested a surface mounted ceramic antenna instead of the usual wire or whip-antenna (which was rejected in later designs because of the poor performance)

Project info at fishpepper.de  and the GitHub repository here: tinyOSD and tinyFINITY.

Check out the video after the break.

The “terrible” 3 cent MCU – a short survey of sub $0.10 microcontrollers

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Tim (cpldcpu) writes:

Like many others, I was quite amazed to learn about a microcontroller sold for only 0.03 USD via the EEVblog last year. How was this possible? Many assumed this was a fire sale of an old product. Digging a bit further, it became apparent that there is an entire market segment of ultra-low-cost microcontrollers. Almost all of them are products of rather unknown companies from China or Taiwan. This write up summarizes my findings in this rather peculiar niche.

See the full post on Tim’s blog.

Teardown and modification of an Electrophoresis power supply

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Kerry Wong did a teardown of an EC600-90 electrophoresis high voltage power supply:

Electrophoresis power supplies are commonly found in biology and other life sciences laboratories. These power supplies are usually capable of supplying high voltages and high currents required for gel electrophoresis–a method used for separating DNA, RNA and other protein fragments based on their size and charge. There are many used electrophoresis power supplies out there in the second hand market and can be bought quite cheaply. I am curious whether these electrophoresis power supplies are suitable for electronics lab use as a lab grade high voltage power supply can be quite expensive. So I recently picked up one from eBay to take a look.

See the full post on his blog.

Check out the video after the break.

App note: Silicon Labs’ TS3004 VS. the CMOS 555 – Determining lowest supply current for battery-powered applications

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Good read on this app note from Silicon Labs comparing their low power but obsolete timer. Link here (PDF)

The 555 timer is the workhorse of ICs, with close to a billion of them manufactured every year. Introduced in 1972, the 555 is still in widespread use because of its ease of use, reasonable price, and good stability. It can be found in a wide variety of applications for oscillation, timing and pulse generation. But what if you need a timer IC for ultralong life, low-frequency battery-powered/portable applications where a low supply current is a requirement? Is the CMOS555 timer your best option?

App note: Single-cell regulated Q-pump draws low quiescent current

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Q-pump an alternative to inductor charge pump boost regulator for low power and sleepy microcontroller from Silicon Labs. Link here (PDF)

In the switch-mode power supply world, capacitor-based charge pumps (or Q-pumps) generally aren’t useful for heavy lifting, but work well in niche micropower applications where space is at a premium. They work best in applications where the output voltage is an integer multiple of the input voltage, which are operating points that result in peak efficiency. However, they can also shine when powered from a variable input like a battery, particularly when quiescent battery drain is more important than heavy-load efficiency. This might be the case when powering a microcontroller that spends most of its life sleeping.

Sweeperino, Arduino based test instrument

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Ashhar Farhan (VU2ESE) made an Arduino based sweeper for ham radio homebrewing, that is available on GitHub:

The Sweeperino a very useful Arduino based test instrument. It is the following:
*A very stable, low noise signal generator from 4 MHz to 160 MHz without any spurs
*A high precision power meter with 90 db with 0.2db resolution
*A sweeper that can be your antenna analyzer, plot your crystal or band pass filter through the PC
*It fits in your jacket
*It can be assembled in an evening
*Costs about $50 in new parts

See the full post on VU2ESE’s radio experiments blog.