Mullard 3-3 Amplifier project (part 2)

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Dilshan Jayakody writes:

This is a second article related to Mullard 3-3 Amplifier Project and in this article we introduce HT transformer and HT power supply related to this amplifier. As mentioned in previous post, power supply unit of this tube amplifier is constructed using 400V 5A bridge rectifier, 220µF (400V) and 82µF (400V) electrolytic capacitors.
The most vital component of this power supply is HT transformer and due to limited availability we construct this transformer by ourselves.

More details at Dilshan Jayakody’s blog.

An S/PDIF sound card using the PCM2906

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Joesugar writes:

When S/PDIF became available in the Teensy Audio Library I thought this might be the solution to ground loop problems I’d been having when interfacing projects to my PC. However, I quickly realized I didn’t have any sound cards with an S/PDIF interface.
In the belief that I’d rather build than buy I decided to update one of my previous projects, a PCM2904 based sound card, to include an S/PDIF interface.

More info at Computer/Electronics Workbench site.

PWM dimmer for LED lighting

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Lukas Fassler has published a new build, a DIY PWM dimmer for LED lighting:

I have recently moved to a new apartment and was looking for a PWM dimmer to control some 12V LED strips. I thought that should be easy enough nowadays but it proved more difficult than I thought. All I found either didn’t meet my requirements, were uggly or expensive. So I decided to build my own, tailor-made to my needs.

Project info at Soldernerd site.

Quantifying cooling

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Chris Palmer (a.k.a nophead) has designed and built this coolometer project to quantify the cooling effectiveness of various fan:

I was wondering about how I was going to calibrate the airflow reading but then realised that the flow rate is not actually what I am interested in. It is the cooling effect the airflow has, which is what I am directly measuring. The result is simply the extra power needed to maintain a target temperature and is a measure how fast the bulb filament is being cooled. So rather than an anemometer I decided to call it a coolometer. Unfortunately Futurama used that name first. Rather than displaying megafonzies mine displays milliwatts!

Project info at HydraRaptor blog.

Programmable CW Morse Keyer / beacon

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Marko Pavlin has designed a Mini USB dongle with STM32F0xx , he writes:

Mini USB dongle with STM32F0xx is suitable many for simple, mini projects. I attached speaker to Timer14 PWM output (Pin PA6) and LED (or optocoupler connected to PTT) to GPIO pin PA0
The provided software is based on USB Virtual Com Port (VCP) device. The setup is done with command line interface using terminal from any PC. The setup is stored in the internal flash and PC is not required for normal operation. The mini beacon keyer can be used when powered with 5V.

Project info at Mare & Gal Electronics.

Nixie thermometer

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Luca Dentella has developed a Nixie thermometer to measure the temperature of the liquid cooling system, that is available on Github.

 I decided to log the design and the development of the project in ten blog posts. They show my “divide et impera” approach: I divided the whole project in small tasks (drive a nixie with Arduino, read the temperature from a thermistor, use an rgb led module, prepare the first prototype on a perfboard, design the pcb, assembly the final product), all described on my blog with examples and videos.

Project info at Lucadentella.it

Check out the video after the break.

Nixie thermometer

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Luca Dentella has developed a Nixie thermometer to measure the temperature of the liquid cooling system, that is available on Github.

 I decided to log the design and the development of the project in ten blog posts. They show my “divide et impera” approach: I divided the whole project in small tasks (drive a nixie with Arduino, read the temperature from a thermistor, use an rgb led module, prepare the first prototype on a perfboard, design the pcb, assembly the final product), all described on my blog with examples and videos.

Project info at Lucadentella.it

Check out the video after the break.

Happy Valentines day!

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Sjaak built this blinky heart for his girlfriend this Valentines day. It is based on a MAX7219 and a PIC16f1823:

My girlfriend persuaded me to start this hobby side project and as a favor I made her this blinky heart. I don’t want to buy a standard trumpery from the shop, so I locked myself up into my mancave and started to solder and code as a monkey. I put a MAX7219 8×8 LED matrix, a PIC16f1823, a CR2032 coin cell with holder and a vibration switch together. Most of the stuff I had already lying around so I started immediately.
Somewhere on the web I found a small tutorial how to use the MAX7219 with the buspirate. That made it really simple for me to test the display for faults and get myself familiar with the command set.

Project info at SMDprutser blog.

‘Magic tree’ project

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Dilshan Jayakody has published a new build, a ‘Musical trees’:

“Musical trees” is a part of creative arts installation and this project is capable to produce different audio tones by detecting human touch to its attached plants. Existing version of this driver is capable to monitor 8 plants and produce different sounds for each plant.
This project is build around PIC16F628A 8-bit microcontroller and PT2399 echo processor IC. To drive the sensor electrodes we use pair of CD4011 quad 2-input NAND gate ICs. This prototype use TDA7052 1W audio amplifier IC to drive the speaker(s).

More details at Jayakody’s blog.

Check out the video after the break.