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adv
10-12-2004, 11:42 PM
Hi there
i m planning 2 make a line following robot so can u pls recoomend me some gud IR Refl. sensors....one i knw is TCRT1000 so can u guys comment on dat n suggest me others 2....actully i dunno it's working dat well can u guys give some light on dat 2.....thnx alot...bye

ice
10-13-2004, 08:33 AM
visha sells ir sensor pairs for 14Rs[transmitter and detector].
Be sure to buy as many as u can....The can blow up easily if u give them to much current or overvoltage them
ice
//Gerry

Guest
12-12-2004, 10:24 PM
Does anyone know any IR LEDs and IR Photodiodes with narrow beam widths? And does anyone have an idea of which sensors does Visha sell?

mandar
12-13-2004, 12:42 AM
i have my question to add to this too.. :)

i did buy an ir pair... but i dont know how to use them ... :oops:

i mean.. the sensor has three pins... like a transistor (i guess thats what it is) but how do i connect it.??... its got the number .. 3382 on it (thats what the vendor said is the number of the rx) ... and i cudnt find nethiing abt it on the net. ...
also how do i test if the ir led works or not.... ...

thanks a lot...
mandar

ashish_bhat
12-13-2004, 01:11 AM
i have my question to add to this too.. :)

i did buy an ir pair... but i dont know how to use them ... :oops:

i mean.. the sensor has three pins... like a transistor (i guess thats what it is) but how do i connect it.??... its got the number .. 3382 on it (thats what the vendor said is the number of the rx) ... and i cudnt find nethiing abt it on the net. ...
also how do i test if the ir led works or not.... ...

thanks a lot...
mandar

those 3-pin recievers could be photo-transistors. in that case u can use them as follows:
first u'll have to figure out the terminals. do it as u would figure out terminals of a normal transistor but cover the transistor with ur hand so that no light is incident on it.
now to use them: (for npn type)
1) ground emitter
2) connect R between collector and Vcc
3) base can be left open or a large R can be connected between base and ground.
4) output taken from collector.

for pnp type use the same procedure u use to convert a npn circuit to pnp one.

the collector current Ic will be proportional to intensity of light falling on the transistor. so Vo = Vcc - Ic x R will be your output signal.
u can start with R around 10k and change it as required. (if transistor is saturating then reduce R, if output signal is too low increase R)

the 3-pin recievers could also be those modulated type recievers. in that case usage is very different.

to check my IR LEDs, i just use my camcorder to SEE the IR LED glowing!
u can use a digicam, webcam, camcorder etc.
that is the easiset way, but in case that is not available, make the above circuit and use it to test the LEDs! :D

and yes the base resistor will provide some sort of negative bias point. no collector current will flow till intensity is greater than some threshold intensity. higher this R the lower this threshold intensity will be. for R = infinite (base open) thereshold intensity = 0.
u can try a 100k resistor in series with a 200k pot as the base resistor.

Ashish

addy
12-17-2005, 01:17 PM
hi,
if u r talking about tat black colored ir receiver from vishay....
tat is tsop17xx.
if its tsop1738..... u need to modulate the transmitted ir at a frequency of about 38 khz.. because its tuned to receive only tat.
the 1st pin is gnd, 2nd is vcc, and 3rd one is output.
it follows negative logic, i.e. output becomes low wen eva the receiver receives ir back.