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Dirk Grappendorf
grappendorf.net
grappendorf.net
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Control a 2-port KVM switch via HTTP over WLAN with an ESP8266
http://www.grappendorf.net/projects/wlan-kvm-switch.html

Recently I bought a small and inexpensive 2-port KVM (DVI/USB) switch that I installed with the intention to switch between my Linux and Windows workstations. Marketing promises that I could switch by pressing Scroll-Lock or Ctrl on my keyboard two times. The sad reality is: this only works if the currently active workstation is the Windows one (WTF!?).

This article briefly describes how you can add an ESP8266 module to a KVM switch, which allows toggling between the two computers by sending a REST/JSON request via WLAN. You can then define global keyboard shortcuts that simply call httpie to send the toggle request to the switch.
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Control a 2-port KVM switch via HTTP over WLAN with an ESP8266
http://www.grappendorf.net/projects/wlan-kvm-switch.html

Recently I bought a small and inexpensive 2-port KVM (DVI/USB) switch that I installed with the intention to switch between my Linux and Windows workstations. Marketing promises that I could switch by pressing Scroll-Lock or Ctrl on my keyboard two times. The sad reality is: this only works if the currently active workstation is the Windows one (WTF!?).

This article briefly describes how you can add an ESP8266 module to a KVM switch, which allows toggling between the two computers by sending a REST/JSON request via WLAN. You can then define global keyboard shortcuts that simply call httpie to send the toggle request to the switch.
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Yet another Arduino-based signal tower (aka stack light) that can be used to display the status of anything that requires immediate maintenance in case of a failure (I'm using it as a continuous integration status indicator for our agile software development team).

The article linked down below describes the construction of this signal tower with a WLAN interface and a simple HTTP REST API. 

http://www.grappendorf.net/projects/signal-tower.html
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Yet another Arduino-based signal tower (aka stack light) that can be used to display the status of anything that requires immediate maintenance in case of a failure (I'm using it as a continuous integration status indicator for our agile software development team).

The article linked down below describes the construction of this signal tower with a WLAN interface and a simple HTTP REST API. 

http://www.grappendorf.net/projects/signal-tower.html
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I finally finished my 6502 CPU retro computer system.

http://www.grappendorf.net/projects/6502-home-computer

https://github.com/grappendorf/homecomputer-6502

The 8-bit MOS 6502 CPU was used in many popular home computers of the 1970s and 1980s like the Commodore 64 or the Apple II.

This project started with some basic circuit designs on a breadboard, went on with the production of a PCB, the development of firmware software, and finally finished with a custom designed 3D printed case.

I have published a short seventeen part article on my website that illustrates the complete development process.

All the schematics, PCB design files, and the source code are released under open source licenses on Github. The repository also includes various versions of these files, so that you can retrace my development progress.
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I finally finished my 6502 CPU retro computer system.

http://www.grappendorf.net/projects/6502-home-computer

https://github.com/grappendorf/homecomputer-6502

The 8-bit MOS 6502 CPU was used in many popular home computers of the 1970s and 1980s like the Commodore 64 or the Apple II.

This project started with some basic circuit designs on a breadboard, went on with the production of a PCB, the development of firmware software, and finally finished with a custom designed 3D printed case.

I have published a short seventeen part article on my website that illustrates the complete development process.

All the schematics, PCB design files, and the source code are released under open source licenses on Github. The repository also includes various versions of these files, so that you can retrace my development progress.
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I hope you all had a nice #ArduinoD14!

To celebrate this day, i finished a first pre-alpha, technical preview, in no way usable, i.e. production ready version ;-) of my CoYoHo home automation system.

http://www.grappendorf.net/projects/coyoho

Information about this system, Eagle schematics and layout files, device firmwares and the server source code are available in the CoYoHo section of my website.

All of the remote devices of my home automation system are developed with the Arduino software framework. I'm not using the Arduino IDE, but Eclipse together with my own compilation of the Arduino core and a set of Arduino libraries. This combination provides a highly productive, fun to use and professional environment for developing embedded system applications.

With all the available Arduino libraries you get things done with the least possible expense. And most important for me: all of this works on the Linux operating system.

So a big thanks and thumbs up to all the people in the Arduino community! Keep on hacking!

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If you use XBee modules for wireless communication with your embedded devices and you'd like to use Ruby to talk to them from your workstation, then my xbee-ruby gem might help. Despite that it currently supports only a small subset of the XBee API Mode 2, it is sufficient for sending packets to and receiving packets from remote XBee devices. I use this gem on the server side of my CoYoHo home automation system. The gem can be downloaded from RubyGems.org and the source code is hosted on GitHub.

http://www.grappendorf.net/software/xbee-ruby

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BeagleBot: A cylindrical, differential drive robot controlled by a BeagleBone Black

I've built a robot for the Coursera course "Control of Mobile Robots", where you can "Learn about how to make mobile robots move in effective, safe, predictable, and collaborative ways using modern control theory."

I posted some pictures of my BeagleBot. Later on i'll add some more documentation and download links for the software...

http://www.grappendorf.net/robotics/beaglebot
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