Acorn BBC Master and electron cartridge breakout

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The Acorn Master cartridge breakout board by Simon Inns:

This project provides a simple breadboard adapter/breakout board for prototyping cartridges for the Acorn BBC Master and Acorn Electron 8-bit computers.
The design consists of two PCBs, the first plugs into the computer’s cartridge slot and the second is designed to plug along the edge of a standard 2.54mm pitch breadboard.  The two boards are connected by a length of 50-way ribbon cable.

Project info at waitingforfriday.com and GitHub repository here.

USB seven segment display module

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Dilshan Jayakody published a new build:

This project is about an open source, USB based, 10 digit seven segment display unit. This unit is specifically designed to work with POS systems and banking applications. Initially, this system is developed to work with PC based systems, and later it was modified to work with other platforms and applications.

See the full post on his blog.

Making a SPL dB meter

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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.

App note: Meeting transient specifications for electrical systems in military vehicles

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Hardened circuit protection against voltage spikes and surges tackled in this app note from Vicor. Link here (PDF)

Electrical systems in military vehicles are normally required to meet stringent transient requirements. Typical of these specifications is the MIL-STD-1275B. Although the specified levels of these surges and spikes are outside the capability of Vicors Maxi, Mini, Micro Series modules, it is quite possible, with simple circuitry, to make the 24V input (18 – 36V input range) DC-DC converter modules compliant to these specifications for the 28V vehicle voltage system. Other electro-magnetic compatibility requirements, such as MIL-STD-461E and/or DEF-STAN 59-41, apply to military vehicles, but these are outside the scope of this application note. In order to meet additional conducted emission requirements an input filter, preceding the transient protection circuit covered in this application note, will be required.

3 cent PMS150C MCU driving 300 WS2812B LED’s

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Driving 300 WS2812B RGB LED’s with “the 3 cent microcontroller” – the Padauk PMS150C.

The 3 cent Padauk PMS150C is.. Interesting to say the least. First of all there’s a lot this little MCU doesn’t do. It doesn’t have a lot of code space (1K Word), it doesn’t have a lot of RAM (64 bytes) and it doesn’t even do hardware multiplication. It doesn’t have an instruction for loading data from ROM either(Though there are ways of getting around this – but that’s a subject for another post). And of course – you can only program it ONCE.

More details at ABNielsen.com.

Check out the video after the break.

Using 0603 surface mount components for prototyping

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Kenneth Finnegan shared a tip on using 0603 SMDs on the .1″ perf board:

As a quick little tip, when I’m prototyping circuits on 0.1″ perf board, I like using 0603 surface mount components for all of my passives and LEDs, since they nicely fit between the pads. This way I don’t need to bother with any wiring between LEDs and their resistors, since I can just use three pads in a row to mount the LED and their corresponding current limiting resistor and just need to wire the two ends to where they’re going.

See the full post on his blog.

App note: Intelligent lighting controller measures ambient light and tracks time

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Implementation on ambient light and time tracking luminaires controller from MAXIM Integrated, Link here

This reference design explains how to design an intelligent lighting controller that senses and measures the ambient light level with an ambient light sensor (ALS). Equipped with a real-time clock (RTC), the controller also knows when to turn lighting on or off at specified times.

App note: Selecting the right CMOS analog switch

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App note from MAXIM Integrated digging on the basics of CMOS analog switches and the latest improvement on them from the standard one. Link here

Integrated analog switches often form the interface between analog signals and a digital controller. With the large number of analog switches on the market today, there are many performance criteria for a product designer to consider. There are also many application-specific switch circuits that have evolved from the standard CMOS switch developed over 35 years ago.