calling all Car and Tractor specialist

[Kipper4]

Thanks guys

[Kipper4]

John your test doesnt work.
just to be sure i tried it on other diode too.

I wonder if they ever lit up at all. I was under the impression I wouldnt see a glow at all.
Dont ask "Something I read on the net"
Then I crack open a mouse and the led in there is like a super bright red. Maybe thats what it is and not an infra red led. It glows.

I did order 10 more pairs last night.

Still havent done your test yet sam.

[Kipper4]

Something defo went wrong last night when testing because I also fried the std 5mm led.

[Kipper4]

"if you point the camera at the LED (while LED is on) and look through the view screen, you should be able to see the LED.
You can check this by looking at a TV, stereo, whatever remote. The LED in the end of these should come on when you press a button."

Tried this with a remote and yes it does.



I'll give it a whirl with the IR 3mm leds.
lab report.
Nope I SMOKED 'em. Ziltch on the camera. As dead as the proverbial parrot. They are NO more.

[Kipper4]

Maybe next time I'll try this beauty.

https://circuitdigest.com/electronic-circuits/ir-sensor-circuit-diagram

[amptramp]

Your test circuit has no resistance in series with the LED.  As soon as the transistor is biased into conduction, unlimited (at least, much higher than needed) current flows through the LED.  You need a resistor in series with the LED to give you controllable current.  A resistor in series with the collector will protect the transistor and the LED but will not give you linear control - it would be on/off.

[Kipper4]

Cheers Ron

Judging by the little video for the lm358 circuit it is not linear either.

I did get the transistor circuit working for about 5min before it smoked the 1M pot and blew the IR leds and Photodiode. and it was working quite well just wasnt sure about the range of near / far.
Edit; with a 2N5087 pnp
Edit 2: I just found a pair of BC560 same series and data sheet as the BC557.

[amptramp]

D2 and D4 pull the transistor base to full conduction and they have no current limiting either.  The only way one of them survives is that one has a slightly lower forward voltage and keeps the other from conducting.  The type of circuit you need is a current source because the current is what you want to set.  There are a couple of examples of a current source here:

http://electronics.stackexchange.com/questions/28546/what-exactly-is-a-current-source

[deadastronaut]

Just double checked over my breadboard,  and the schemo i posted is fine...

Works well, around 3" range..

[duck_arse]

kipper, there's two types of mouse. one has a ball that drives some rotary encoder wheel things (2 off), with an IR Tx/Rx pair looking thu the holes. the other has a pair of laser diodes that look at the surface as it moves, but I don't know if they are IR. they usually shine a bright red light on the surface as well. I went back to ball mouses, couldn't tame the optical ones.

[Kipper4]

I rebreaded the transistor circuit and it worked for a while.
This breadboard is a piece of trash.
after swapping a 2n5087 for a bc560 its stopped working again and the voltages are slammed at the +rail.

Whats your volts Dead un please?

@Duck un thanks for the info bud.

[Kipper4]

What kinda pot are you using Dead un please cuz I've now fried 3x my little tayda 9mm breadboard pots.
This makes me sad.........

[deadastronaut]

yeah, im using a 9mm pot on breadboard same as yours...

hang on...i'll knock up my breadboard layout...as i have it ok.

[deadastronaut]

here ya go...using 9v pp3 battery...

bc557..

[Kipper4]

Thanks Rob I'll have anther go later.
No body  sad battery I'm using a wall wart with 1amp.

[deadastronaut]

should be ok...

i just rigged it up to my 10 way daisy chain...9v, 2.4 amp adapter..

was fine..

better response too..

[Kipper4]

Ok thanks
I got to boss this I can see it being really useful and fun for my grandsons robot projects.
I must have the fecker wired wrang.
Cheers

[Kipper4]

I breadboarded it the same as yours Rob and its working and the range (distance) is decent.
lab report. drum roll..... da da daaaah

under normal interior light conditions

the first thing to say is my IR transmitters are defo gone to the parrot sanctuary in the sky.
It didnt stop the IR detectors working in circuit.

The only leds i could get to work with it where 5mm diffuse green and diffuse blue.
none of the super brights really shone. super brite white, yellow, red or 3mm diffuse red.
suggesting it needs a higher Fv led.

using a 2N5087 pnp


Can It be done with npn or reverse the led so it goes from dark to light. Instead of just light to dark. Maybe some functioning IR transmitter will cure this.

[deadastronaut]

cool,


''Can It be done with npn or reverse the led''

john referred to this earlier, havent tried it though...

[Kipper4]

Yeppers must have missed that post I'll try it later.
Also found a similar functioning circuit with a mosfet.
I'll have a go at that too and yock up a drawing.
Rich