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Showing posts from March, 2007

How to setup 2FA On Linux SSH Login

  This is a simple setup guide to enabling Two Factor Authentication (2FA) on Linux SSH login. I this article I wont go deep into setup and issues that I have faced when implementing this. First thing is first Update your system first. I have used Ubuntu 20.04 and it is always up to date. To enable 2FA you need to install google authenticator modules sudo apt install libpam-google-authenticator Configuration for PAM and SSHD Add the the following line to /etc/pam.d/sshd and After adding this line please restart the sshd services.  auth required pam_google_authenticator.so Go to /etc/ssh/sshd_config and check if the following line exist. Default value will be "no" so change it to "yes" to activate.  ChallengeResponseAuthentication yes Configuration for Authenticator In the terminal run google authenticator command It will ask few things to acknowledge by user. Details you can see from the below video. Once this part is done you are ready to use the 2FA in ubuntu. T...
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ADC- Analog to Digital Converter

This afternoon i was hard cording some ADC codes. Actual thing i want to do is micro controller's ADC will analyze the given voltage . Actually i am continuing my voltmeter project. I did analog part from LM358. actually an differential amplifier, it handles the high voltage and gives an out put range from 0 - 5 volt. After some calculations i finally solve the puzzle. Now my micro controlled voltmeter is able to display variable voltage from GLCD (Graphical LCD). Next step is to fine tune the analog circuit and add a new feature or function to display load current. Many experiments are hold for few days, thing is me too busy some times... ;)
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Blog AD on LCD

These days i am fighting with LCD's, both graphical and character. I did some test c code and tadaa its there in the Graphical LCD. Looks so cute. :P
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μ -Stepper motor controller

Today i found one of my old projects, actually experimenting stuffs. This is thing is a stepper motor controller. I think many people out there knows whats Stepper Motors are and how it works. Usually this type of motors are in printers and photocopy machines..etc. Actually the circuit i made was to interface a stepper motor to an micro controller IC so i can write a code to turn the motor to different degree and so.. usually this type of applications are used in Robots . Before i wrote the operating code from assembly language and now i have changed it to C language and its simple and easily understandable for anyone. Hopefully some one will built a robot soon. ;)
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Voltmeter continued

See some pictures of the voltmeter display board. Its not yet completed and will take few days to program and make a use of it. Problem is i am too busy and my friend wh0kn0wz is is also little busy with some projects. So once its done i will let you all know. For the time being enjoy the pic's. ;)
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Voltage monitoring from Microcontroller

These days i am very busy with office works but spends time for my projects. The power supply that i am working on is still getting modified and to day i made the display part for it, hopefully tomorrow i will complete the brain part (Micro controller). Hold on for he pic's..... ;)
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My new power supply.

Its been more than two weeks that i am designing a new bench power supply with adjustable dual polarity and non adjustable 5V. Which includes safety fuse and LCD or 7Segment display to monitor current and voltage.. but still not decided to which to put. The transformer used in the power supply is re wound to make it center tap. Before it has only one coil in secondary so i disassemble the transformer and re wound it again for my needs. The rectifiers are circuit's taken from a computer power supply from junk. The diodes in the rectifier is high current diodes so i planed to cut the part out from a power supply. For variable +15V i used LM317 and for -15V i use LM337. Still i am waiting for my component orders. Once 5K VR arrives i will finish this project.
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PWM, Fan controller

This circuit basically goes to PWM (Pulse Width Modulation). From this circuit i controlled a PC power supply fan. when the variable resistor is turned, the fan starts operating in a very slow speed and when the VR is turned more the speed of the fan increases. If you want you can just modify this circuit and use and temperature sensor and trigger the fan to cool the system. If you guys need the schematics for modifications, i can give it..
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PIC Board..

I am waiting for my PIC micro controller board and this is my first time that i am using an original development board. All these days i have used my own designed programmer and test board. But once i changed my developing terminal for a laptop, it did not work. cause the serial port peak voltage from laptop is 7.5V which is useless for programming. At least 12.7V or 13V is needed to program a PIC micro. My old programmer still works in PC . If anyone interested on it i can give you an schematic of it.
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Intro..

Hi, i am forbiddenhex and this blog will update you all the electronics projects that i am doing and planned to do. Before i haven't seen any Maldivians interested on electronics designing and development, but now things have changed much and i like to share my knowledge with all those who want to study electronics and need support for that. within few days time i will upload some pictures of my ongoing project. So don't forget to peep.
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