March 7th, 2009

Universal remote control

Universal remote control

Are you tired of carrying around one remote for the TV, one for the DVD player, one for the sound system and the list can go on. There is the possibility to buy one “good for all” remote control but it will cost you a few hundred dollars, off course there is an alternative for less money, make your own DIY universal remote control.

Any valid RC5/RC6 will be displayed on the LCD, and any code can be sent with the on board IR led’s, the LCD is the common 2ื16 HD44780 compatible type.

The hardware is very simple, the software is written in basic and made available by the author.ย The Dell TV deals page sometimes has universal remotes like the Logitech Harmony One for heavily discounted prices.

I recommend this project for those interested about the RC5/RC6 codes, it can be a great alternative for radio based remote control for robotics, as you can see in one of my previous articles: IR remote robot

Universal remote control: [Link]

February 15th, 2009

IR light dimmer

IR light dimmer

This can be considered an old project, and yes you can buy the commercial version quite cheap too, but in case you want to build one, this is a working project. The source code isn’t made public, but since it was written in assembler language probably wouldn’t be any use at all.

It is a compact and clever dimmer, with capacitive power supply and a small PIC micro controller, it can be mounted in very small space. The learning process is straight forward and explained step by step. It has also a 110V/60Hz version of the hardware and complied firmware.

Keep in mind that this device uses the potentially lethal mains voltage, care should be taken when testing and mounting, use good quality isolation and disconnect from mains when handling.ย  When powered up, please don’t touch the triac to see if it gets hot because you will get zapped, this is a basic mistake, and maybe the most common among hobbyists.

IR light dimmer: [via] [Link]

January 22nd, 2009

Object tracking robot

Object tracking robot

This is an advanced robotics project, the robot arms follows a moving object, anyway that’s the idea. The arms moves a little sloppy, it surely isn’t in the final stage of development, but the author explains what problems encountered.ย  The motion is detected using IR leds and receivers, and subtracting the ambient light from the readings to get the reflected light from the object which is tracked.

If you are interested in motion tracking this is a good place to start, my opinion is that the analog part needs to be reviewed, the IR leds should be mounted inside a tube, otherwise interferes with the reflected light and reduces the sensibility.

Object tracking robot: [Link]

October 10th, 2008

Super TV-B-Gone

I liked the tvbgone kit from Ladyada the first time i saw it but i never had the time to build it, until a week ago. But than i decided to build a more powerful one that could turn off TV’s from even greater distance. I came up with a design that consists of 48 IR LED’s and a ATmega8 that will send the signals to the LED’s.

the led board
Unfortunately i wasn’t paying attention on a small paragraph from Ladyada that was saying “Use 940nm IR LEDs.” so without knowing i bought 860nm IR LED’s (L53SF6C from Kingbright). I did not knew at that time that this is going to affect the distance at which the device works. Why L53SF6C ? they seemed nice because at 50 mA they have typical 100 mW/sr so allot more power than the F3(940 nm) series which had 30 mW/sr at 50 mA.

I arranged the LED’s in 4 rows of 12 pieces and the resistors fit quite nicely between the LED’s. I used four BD139 NPN transistors to drive the rows. It took me hours to drill and then solder this board(48 LED’s and 48 resistors mean 192 holes plus the other parts)

super tvbgonesuper tvbgone

the controller board
The controller board contains an ATmega8 chosen because of it’s 8k memory needed to store all the codes, an 8 MHz crystal, an LED, a tact switch and some resistors and capacitors. I designed the board so that it can also be used for other projects.

super tvbgonesuper tvbgone

the code
It took me some time to adjust the code from tiny85 to ATmega8, getting the timers right was tricky but i managed to get it done. Also i had to delete a couple of codes to fit it in the 8k’s of the ATmega8.

the power
The whole project is powered from a Nokia BL-5B battery which was ugly fitted onto a peace of PCB ๐Ÿ™‚ . I can’t seem to find a decent socket to hold such a battery. I’ve run the circuit for over a week every day and the battery is keeping up, and when it gets discharged I’ll simply charge it inside of an old nokia phone.

super tvbgone

Testing it
Well as you can imagine the first thing i did was to test it on the TV’s in my place, it worked perfectly. Next i wanted to test it on a larger scale so i took the device onto a nearby supermarket were they have a bunch of Tv’s onto a wall. I had to conceal the device somehow so they don’t kick me out of the store ๐Ÿ™‚ so i placed the device inside a CD case. I don’t know how much the case is obstructing the signal, but it was turning off TV’s from a distance of 20 meters.

super tvbgone

Probably choosing the right wavelength LED’s would double the distance, and by using a clear case the distance would double again, but that’s just a guess.

The boards were designed in Eagle and fabricated by me using the photo etching technique.

I’m planing to build a newer version, in fact i already sent the files for PCB fabricating. This new version will use only 4 LED’s just like the original design, and will be smaller thus easier to conceal and it will also use ATmega8 for the controller. I’ll post pictures as soon as i get it done.

some more pictures..

super tvbgonesuper tvbgonesuper tvbgonesuper tvbgone

downloads

Basic Stamp IR remote interface

The function of the device is very simple. Any IR remote than can be programmed to use the Sony protocol will work. The module outputs the device code (TV/VCR/DVD/AUX) and the button pressed, so the device can be used on as many different projects as your remote has devices (usually four). It is simple and cheap to make, and works really well.

Basic Stamp IR remote interface: [Link]



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