Network & Security IT - Le RSI
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Motorized Camera controlled by the telephone
Each time I tried to phone one of them, I was unable to understand what he said : I tried but never succeeded in teaching any human language to them. So, I created this motorized Camera controlled by the telephone, in order to supervise them when I'm at my office.
The system is made of 3 parts:
- 1- a private PBX based on Asterisk: this Linux PC is connected to the PSTN. When it receives a phone call, it converts DTMF signals to commands sent into an asynchronous V.24 interface (RS-232-C),
- 2- an electronic box based on a micro-controller that receives commands from a V.24 interface and is able to drive a motor (stepper),
- 3- an USB camera attached to the stepper, broadcasting to the Internet.
Here are the schematics:
SN476 + L293D both from Texas Instruments
What about the software parts ? - The assembler code for the PIC is available here.
- In your PBX dial plan (Asterisk configuration file extensions.conf), you need to add the left and right actions (in this example, press 7 and 8 to let the camera rotate left and right):
exten => 7,1,System(/bin/stepper-left-digium.sh)
exten => 7,n,Goto(s,begin)
exten => 8,1,System(/bin/stepper-right-digium.sh)
exten => 8,n,Goto(s,begin)
- These shell scripts call /bin/stepper (see stepper.c).
IP phone to analog phone interface circuit
At work, people usually do not get an analog phone line anymore since numeric or IP phones appeared. See how to connect your old analog device (modem, wireless DECT phone, Minitel) only using your IP phone to get the network access: read this.
Very low cost 20MHz signal generator for ham radio HF power amplifiers testing
Learn how to make a 20MHz HF signal generator using a few simple discrete analog components. Moreover, see how a 33 years old Tektronix oscilloscope gives better results than a numeric one bought recently. The whole story is here.
Split tunneling with Cisco
Enabling split tunneling with Cisco IPsec VPN Linux client software is always possible: read this.
Modelling IEEE Spanning Tree protocols using an UML Class Diagram
To really understand the dependencies between the many Spanning Tree protocols, I wrote an UML class diagram describing their relationships here.
Motorized camera controlled by the telephone
This project demonstrates how to drive a camera from the telephone line, any details here.
My Former Web Site
Since 04/26/01, I maintain a web site named www.fenyo.net. Since I made many updates recently, click here to access the original content, where old informations are kept. The photo is also from 2001 :-)
Agnes' Web Site
Agnes, my wife, maintains a web server where you will find plenty of original resources : free software from her own production, probability courses, exams' corrections, photos of her trips in the US... Do not hesitate to visit her site, she will be glad to see her access.log growing !
Canardou's Web Site
Canardou has always been for me a friend that really matters, helping me in every situation. According to informations currently available, Canardou could be affected by the H5N1 virus. So, for a few weeks, Public Health Bird Regulations have made me forbid Canardou to walk away from our appartement. Feel free to take news about him from his personal home page.