Voice-control RC sockets with Google’s AIY Project Kit

Issue 57 of the official MagPi magazine contains a Do-It-Yourself Artificial Intelligence kit made by Google. The build instructions inside issue 57 are straightforward, so that you can talk to an intelligent device within minutes.

However, the installation walk-through in the MagPi57 did not work without problems, therefore I recommend to follow the instructions on Google’s AIY Project Page.

Speech recognition is an amazing feature for the Pi and if you ever wanted to know what “the answer to life, the universe and everything ” is, you should go for it!

The kit turned out to be very popular and it is currently difficult to get hold on it. It is sold out at many places :-(.

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Add action buttons to motionEye for controlling pan-tilt brackets

motionEye is a great piece of software for controlling network cameras with a Raspberry Pi. With motionEye you can watch live video stream, detect motion, record images and videos.

Starting with version 0.30, motionEye can be configured to overlay buttons on top of a camera frame. These buttons will then execute custom commands when clicked. Thus, it is possible control to control a pan-tilt bracket or to toggle IR light for a PiNoir camera.

Here I mounted a PiCam onto a cheap (0.40 €) pan-tilt bracket with two SG90 servos from Aliexpress.

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Monitoring air quality with a Nova PM2.5/PM10 Sensor and Python

It is a major problem in almost all large German cities, that fine particulate matter is frequently exceeding  its maximum permissible value of 50 μg/m3. In a special issue of the Make Magazine (IoT special 01/2017), I read an article about the Nova PM SDS011 sensor, which is using the principle of laser scattering to measure the concentration of particulate matter between 0.3 to 10 μm in the air. The sensor is cheap (about 20 Euro) and easy to use, since it communicates via serial connection.

For placing the sensor into an enclosure,  it is equipped with a nozzle that allows to connect a hose of max. 1 m length. The UART communication protocol requires a bit rate of 9600 baud, with 8 data bit, no parity and one stop bit.

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A Raspberry Pi Moisture Sensor to Monitor Your Plants

For quite a while I am monitoring temperature and humidity in each single room of my apartment. I was inspired by several Raspberry projects, featuring a “Garden Pi“, to monitor my house plants as well, using a probe to measure moisture level of soil.

On the net, one can find many low-cost sensors which are compatible with Arduino or Raspberry Pi. They usually consist of simple PCBs with two electrodes which are pushed into the earth. Moisture is determined by measuring conductivity of the soil which isn’t very reliable for long-term measurements. Cheap sensors are often affected by heavy corrosion, so that  Copper ions will leach out and might poison your plants.

moisture-sensorIn contrast, sensors measuring soil moisture levels by capacitive sensing rather than resistive sensing are much more suitable, because they are made of corrosion resistant material which gives them an excellent service life.

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How to configure RealVNC on a Pi with 3.5” LCD

With the release of a new Raspbian version (2016-09-23) RealVNC have ported their VNC server and viewer applications to Pi, and they are now integrated with the system and PIXEL desktop. With raspi-config, one can enable start of RealVNC at boot time. This is particularly useful, if you’re running your Pi headless a (without monitor), but still want to access the LXDE desktop. RealVNC usually works out of the box, but …

35lcdtft… it doesn’t, when you connect a non-standard display. I recently upgraded one of my Raspberry Pi’s with a 3.5” LCD touch screen, which connects through the GPIO header and has a resolution of 320×480 pixels. Unfortunately, with the display attached, VNCviewer’s desktop size also shrinks to 340×480 pixels which is very inconvenient to read when it is displayed on a 1920×1080 HDMI monitor. Scaling of the window makes its contents very blurry.

However, with some special settings, one can circumvent this problem:

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