Building a direct conversion receiver

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Ryan Flowers over at MiscDotGeek posted a how-to on building a direct conversion receiver:

In the first installment of this series, we discussed why we’re building a Direct Conversion receiver and talked about some basic ideas. In this installment, we explore what it takes to make the leap from a printed schematic to something physical that works. Follow along!

More details at MiscDotGeek.com.

Teensy 3.6 as standalone mediator between USB MIDI and Eurorack

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Sebastian writes:

USB MIDI controllers (such as Launchpad Mini Mk II for example) are common and often quite low in cost.
To interface such a controller with a Eurorack synth system, often a host computer and a MIDI to CV interface might be used. The host computer would take USB MIDI data from the MIDI controller, perhaps store and manipulate that data in some way (e.g. a sequence), using a MIDI to CV converter to then control a Eurorack synth system.
It would be useful to use USB MIDI controllers with Eurorack synth systems without needing a computer and MIDI to CV interface in between the two.
Teensy 3.6 is a great microcontroller that can be programmed using the Arduino IDE. A very useful feature of the Teensy 3.6 is the USB host port.

See the full post on his blog here, Little-Scale.

Check out the video after the break.

Calibrate a magnetic sensor

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Liudr shared a how-to on calibrating a sensor:

First of all, what is calibration? In a general sense, calibrating a sensor makes the sensor provide the most accurate readings allowed by the sensor’s own precision. As an example, let’s assume for a moment that the earth’s magnetic field and any other stray magnetic fields are shielded and you have a uniform magnetic field generated artificially for the sole purpose of calibration. Let’s say that the field strength is 400 mG (milliGauss), equivalent to 40,000 nT (nanoTesla). Now if you align one axis of your magnetic sensor parallel to the direction of the field, it should read 400mG. If you then carefully rotate your sensor so that the axis is anti-parallel with your field, it will read -400mG. If you didn’t do a good job in either alignments, you will read less values, say 390mG, if you’re off by about 13 degrees, because only a portion of the field, which is a vector, is projected along your magnetic sensor’s axis.

See the full post on Liudr’s blog.

Povon home energy monitor part 1, 20 channel system

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Coyt Barringer documented his home energy monitor project called POVON. This first part of a series will detail the 20 Channel sub-metering hardware:

Our initial goal was to monitor power consumption in different parts of the house, and we quickly realized every household circuit would need to be monitored. After some research, small clip on current transformers, or CT’s, looked to be the best sensor for our application. Using CT’s, current draw and thus power on each circuit can be measured. The CT’s would be installed on the wires immediately leaving the circuit breakers in the standard household breaker box. CT’s work great for this because they’re completely isolated and nothing needs to be disconnected to install them.

Project info at lostengineer.com.

Vintage headset conversion

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Quinn Dunki wrote a great article describing the conversion process of a 1980s-era Earmark into a bluetooth headset:

The obvious thing is to convert it to a bluetooth headset for modern use, right? As I previously warned, converting a 1980s-era air traffic control headset into bluetooth headphones is probably the most hipster thing possible. Normally, I don’t allow projects like this around here. But look at these headphones. They are amazing and I love them and I want to use them so I am going to make them bluetooth also shut up. If I have to punch myself as result of now being a hipster tool, so be it. I set out to do this in a non-destructive way that was reversible, at the very least. I wanted to respect the original hardware as much as possible.

Via Blondihacks.

Tutorial: Git with Eclipse

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A detailed tutorial on Eclipse with the EGit plugin by Erich Styger:

There are things which are game changer in the world of software development: one such event was when I started using a VCS (Version Control System): it changed for me how I keep and store my projects and settings. It even changed the way how I deal with non-software related items like documents or other valuable things: I started storing them in to a VCS too.

Via MCU on Eclipse.

IoT LED Dimmer

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Sasa Karanovic shared a how-to on making a IoT LED dimmer:

Making a IoT LED dimmer that you can control via your PC, phone, tablet or any other device connected to the network is super simple, and I’m going to show you how.
I’m sharing my three channel LED dimmer that you can use to dim single RGB LED strip or dim three separate LED channels. I want to be able to control lights above my desk and also mix warm white and cool white strip to give me more flexibility over lighting while I’m working, taking pictures or watching movies.

See the full post on Sasa Karanovic’s blog.

How to build your Energy Load manager

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A detailed instructions of how to build an Energy Load manager from Open Electronics:

When the instantaneous power consumption exceeds the set values, it selectively disconnects the users, in order to prevent the electric meter to cut the power to disconnect.
The management of the electricity users at home, intended as the possibility to define the operating priorities and to momentarily disconnect the ones that may be “sacrificed”, is something that has become important since the coming of the electronic meters. With respect to the traditional ones, such meters are in fact a bit less tolerant towards the overloads, and they could suddenly leave us without power. Given that nowadays the electric meter is almost always outside and that in order to rearm it we should get out of the house; not to mention that the disconnection will probably turn off the computer that is sending files via the Internet, or that a user might not be able to shut down. In order to prevent such a situation, we created the load manager: in the previous installment, we described its hardware. It is now the moment to deal with the software governing it, and with the management of its functioning via the user interface.

Project info at open-electronics.org.

Build a Multisensor Shield for ESP8266

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Rui Santos has a great write-up on building a Multisensor Shield for ESP8266, that is available on GitHub:

In this project you’ll discover how to design and create a Multisensor Shield for the ESP8266 Wemos D1 Mini board. The shield has temperature sensor (DS18B20), a PIR motion sensor, an LDR, and a terminal to connect a relay module. We’ll start by preparing all the hardware and then program it.

See the full post on Random Nerd Tutorials blog.