rePalm

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rePalm project from Dmitry.GR

As I mentioned, none of the native API of PalmOS 5.x was ever documented. There was a small number of people who figured out some parts of it, but nobody really got it all, or even close to it. To start with, because large parts are not useful to an app developer, and thus attracted no interest. This is a problem, however, if one wants to make a new device. So I had to actually do a lot of reverse engineering for this project – a lot of boring reverse engineering of very boring APIs that I still had to implement. Oh, and I needed a kernel, and actual hardware to run on.

App note: 1 kV SenseFET integrated power switch

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App note from ON Semiconductors on their FSL4110LR power switch for SMPS power supplies. Link here (PDF)

Some industrial equipment that are supplied from a threephase AC power source such as industrial drives and energy meters often need an auxiliary power supply stage that can provide a regulated low-power DC source for analog and digital circuitry.

This power supply stage requests special specifications such as;
– Wide AC input voltage: 45 VAC to 460 VAC
– Robust system against high line surge
– Protection against magnetic contact test
– Large output capacitance to keep long hold-up timeafter power-off

Temperature/weather station

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B. Perry writes:

I’ve always been fond of the popular Nixie clocks made from old surplus Soviet nixie tubes. Nixie tubes are no longer made, so they’re hard to acquire. Instead, I took inspiration from “Lixie” displays and made my own Nixie-inspired, LED-powered display. And in an unusual twist (for me, anyway), I didn’t make a clock this time! It’s a weather/temperature display.  I made the parts myself, starting with the electronics. These circuit boards were created on the CNC machine. The “brains” are an ESP8266 chip, which grabs the current weather from the Internet.

See the full post in his blog.

A low cost 2-4 GHz Downconverter from off the shelf dev boards

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Ian Wraith designed and built a low cost 2-4 GHz downconverter for an SDR, that is available on Github:

I recently became interested in exploring some of the signals found in the 2.4 GHz ISM band. The problem is that my favourite SDR (Software Defined Radio) an Airspy R2 only covers up to 1.7 GHz. Initially I looked at buying an SDR that could cover the 2.4 GHz band but found either that they were to expensive , had poor performance or weren’t supported by my SDR control software of choice. So I decided it would be best to build a downconverter to take the 2.4 GHz down by 1 GHz so it could be monitored by my Airspy.

Via rtl-sdr.com.

MAKERVILLA 3.0

MAKERVILLA 3.0

MAKERVILLA is back! It will be held 31 July – 2 August 2019 at the National Design Centre Singapore.

MAKERVILLA 3.0 is a 3-day creative learning experience (CLX) design conference for local and international makers, practitioners & educators to gather under one roof for a time of learning, dreaming, hacking and sharing of ideas.

Find out more on their website at makervilla.com.  Mark your calendar!

6CY7 dual triode valve amplifier

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Josh built this 6CY7 dual triode valve amplifier:

I’ve always wanted to know what the “tube magic” was all about. There is much opinion in the science of music production, probably because music and its perception is highly personal and subjective. Ive always imagined that since transistor amplifiers were “perfect” with their large amounts of negative feedback, great linearity, and low THD that tube amplifiers must add something to sound that generates their appeal. From the reading I’ve done it has to do with harmonics.

More details on imsolidstate blog.

App note: Programmable analog functions

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Another app note from ON Semiconductors about various digital potentiometers application. Link here (PDF)

Analog circuits are made programmable by using digital potentiometers (POTs) to vary the key circuit parameters. This application note provides the analog design engineer with basic reference designs and circuit ideas for controlling the key parameters of analog circuits using digital POTs connected to a computer bus or microcontroller. Analog circuits are made programmable by using digital potentiometers (POTs) to vary the key circuit parameters. This application note provides the analog design engineer with basic reference designs and circuit ideas for controlling the key parameters of analog circuits using digital POTs connected to a computer bus or microcontroller.