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Connect old DEC VT520 terminal to Raspberry Pi

We managed to connect old DEC terminal to Raspberry Pi. Amber font color and that sound coming out from an old keyboard. Check it out.

Control stepper motor with Raspberry Pi over Web

Raspberry Pi has number of general purpose pins available for connecting different external devices like sensors, relays and so on. It is also possible to control different actuators like electric motor with the appropriate driver between Raspberry Pi and motor. One interesting group of motors are stepper motors which are brushless synchronous electric motors that convert digital pulses into precisely defined increments of the shaft position. This property can be useful in many different applications which require positioning. Since the stepper control can be done with Raspberry Pi that can be connected to Internet, we take this control one step further, by exploring possibility of remote stepper motor control, like over simple Web site.

In this article we are going to explain how to remotely (over Web) control stepper motor with Raspberry Pi and appropriate driver board. The software part relies on stepper control with Python, on webosockets for communication and on JavaScript based visualization of the remote stepper motor controller. If you want to see the final results, jump to the following youtube video.

Connect DS18B20 sensors to Raspberry Pi

Digital temperature sensor DS18B20 are very popular among hobbyist because they are quite cheap, provide satisfactory precision for number of applications and can be easily interfaced with microcontrollers or Raspberry Pi. In this article we are going to explain how to periodically measure temperature with DS18B20 sensors that are attached to Raspberry Pi. The readings are stored to MySql database with simple python script.

Raspberry Pi CPU temperature visualization

RPI cpu temperature

In this article we are going to explain how to constantly read CPU temperature of your Raspberry Pi and send the readings to a web page. The communication between server and client web page is accomplished by using websocket protocol. We used Tornado, an asynchronous webserver for python to make websocket connections. To visualize the readings we used free HTML5 charts library called RGgraph. 

Websocket - a simple example

websockets

Websocket is bi-directional communication protocol which emerged recently, with the introduction of HTML5. It enables full-duplex message based communication between client and server, enabling you to make modern dynamic web apps with a little effort. Check our article where we present simple websocket example which is based on Tornado, an asynchronous webserver for python.

Make your Raspberry Pi more secure

By RRZEicons (Own work) [CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons

Raspberry Pi is very common device in DIY Internet-of-Things projects. However, by connecting it to the outside world it becomes a target for different kinds of attacks. With a little effort you can greatly enhance the security of your little fellow. Check them out.

Shutdown/reboot Raspberry Pi with a push button

RPi button

Don't know how to interface a simple mechanical push button to your Raspberry Pi? Check out this article where we use a push button for Raspberry Pi shutdown (long press) or Raspberry Pi restart (short press).

Home monitoring system

We have added the first IoT project. It is a DIY home monitoring system which is based upon Arduino nodes with sensors and NRF24L01 chips for wireless comunication with a main node. The main node collects the measurements from all wireless sensor nodes and send them over serial connection to the Raspberry Pi where measurements are stored into MySQL database. Apropriate Web site for measurement visualization is also developed. See the final result at this page.

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