Amiga Mouse Original Tank Mouse Optical sensor Faulty Help please.

[Audronic]

Hi all

I have an Original Tank Mouse that has a faulty optical sensor .
Does any body know the Brand, model number of these Please.


Thanks    Ray

[darkage]

logically these should be in pairs.  One IR emitter and One IR receiver.

Im not sure what brand / model, but you should do a keyword search like

rectangular LED infrared emitter and IR receiver diode

Examples

http://bit.ly/2kM9QIS

http://bit.ly/2joFg7x

You will need to check the circuit diagram to see if you need to replace the emitter or receiver.  I think this is the schematic

http://pavouk.org/hw/en_amigamouse.html

Theres an upgrade to laser mouse for the original - http://amigastore.eu/en/559-laser-upgrade-for-amiga-mice.html

Edit - You might get better hits if you use the keyword 'phototransistor'

Example - http://bit.ly/2jx71Gj

Hard to find out what the original brand is.  You will probably need to check datasheets and do some calculations based on the circuit given to check that the phototransistor is within spec.    Or maybe just try one with a narrow beam like 30 degrees perhaps  ?

[Audronic]

Hi darkage.

Thanks for all the info.
That really helps identify the receiver ( ? LDR ? Light Dependant Resistor ?).
The circuit is similar, but mine is an early one that came with an OLD 500.

Good to hear from somebody located in Victoria.
Thanks Again      Ray

[Pat the Cat]

Not quite. The receiver part is a diode, not a resistor.

So it goes on/off, depending if light is hitting it. Or whatever wavelength.

That's why you need a matching pair - so the correct wavelength gets sent out by the transmitter, and is received by the diode (receiver).

I don't think the originals are legal for sale anymore, brand new. They were not RoHS tested.

But, I guess a compatible pair is easy enough... one side is Light Emitting Diode (OK, might be infra red, not "light" technically.) The other side is Light Receiving diode (and has to match the LED, or close enough).

Other side is Receiving diode, so it only allows a current flow when the right wavelength is hitting it.

So long as they both work at +5V, and they physically fit in the holes and line up with the spinning disk, I guess it doesn't make much difference which matched pair you use.

Easiest probably to hack an old non-Amiga ball mouse for the parts. Should work OK. It's not like the Amiga pairs were special or terribly different, just the connector was wired different, where you plugged it into the computer.

[darkage]

Not sure how old the mouse is (if the original tank mouse)

Heres an old diagram example - http://www.ianstedman.co.uk/Amiga/amiga_hacks/Amiga_mouse_repair/amiga_mouse_repair.html

Do both sides look the same?  One should be a IR LED Diode (Emitter) and I would guess the other side is photo transistor (receiver)    kind of like a LDR but different package but I would say they would use photo transistors as they are more senstive.

[darkage]

Hi Pat,  

The last schematic Ive posted clearly shows a phototransistor, for receiver

http://www.ianstedman.co.uk/Amiga/am...se_repair.html

The first schematic I posted, doesnt look like it has the correct symbols even for a photo diode.  ie. no arrows on one set of diodes

Edit - You could just buy a pair to make sure its the same wavelength.    It should be a NPN phototransistor for Rx, going by the last diagram.  I assume slightly newer models should be the same before the new looking ones.     It's not voltage that matters so much, its more about getting the one with the right current charactors as per the original ones.

https://www.sparkfun.com/products/241

[Pat the Cat]

I know. But I never saw a transistor with two legs. Have you?

Here's a pic of a Logitech mouse PCB, from the same period. Two connectors on the components, two legs.

https://en.wikipedia.org/wiki/Computer_mouse#/media/File:Logitechms48.jpg

Anyway, that's the way I'd sort it. It's not exactly politically correct, but it should work.

Just replacing one side or the other, without knowing the operating wavelength, is asking for trouble. Replace the pair, it doesn't matter, you know they match.

[darkage]

I know. But I never saw a transistor with two legs. Have you?

A Transistor is basically a switch.   Base is the light senstive material in lieu of a 3rd pin.   The amount of light dictates how much current should pass between collector and emitter.  Therefore just 2 pins.
Symbol is the same as in my last schematic.

[Pat the Cat]

(shrug) Same difference. Both a two legged transistor and a diode are effectively wired the same, doing the same job. Neither will work if plugged in backwards.

Who cares so long as the buggers work? No, nevermind, I'm done here. I don't want yet another bashing.

[darkage]

Not exactly the same.  Photodiodes and phototransistors have different characteristics.

Phototransistor is more senstive than a Photodiode and is the symbol that is shown in the circuit diagram.

[Audronic]

@darkage, @Pat the Cat

Thanks for the info.
I am using Pavel's Circuit as a reference, The other one is totally different.
Included is a photo of the Old Tired Mouse.


Thanks    Ray

[darkage]

OK thats a Tank mouse with a LM339 ic.  

Heres a very good discussion that covers same topics.

http://www.atari-forum.com/viewtopic.php?t=20207#p177259

Someone else on that discussion has picked up that the first diagram is wrong with the strange double diode symbol as well.  They also suggest phototransistor is a more appropriate setup

[Audronic]

Thanks @darkage, Pat the Cat

Thats where i started some days ago.

Thanks    Ray

[darkage]

Official name is 'Phototransistor side looker (looking) package'

I would measure exact package dimensions plus pin width (measured from center pin to center pin) with a digital caliper and then try to match one up with same physical dimensions and supports IR.

List of phototransistor side looking package -

Rs Components (free shipping - no minimum order amount) http://bit.ly/2kOG95B

Element14 - http://bit.ly/2klZTRl

Ordering from Rs Components is cheap, probably worth to get at least 2 different brands to try.   maybe honeywell or osram.   Check acceptable angle, it should be something sensible and not too wide.  Maybe 50 degrees or lower

Edit - You will probably need to get a matching pair, so grab a IR LED (emitter) side looking package as well.  Same brand / operating specs.

Note - Only if your certain that the fault is with the optical sensor.   There could be issues on other parts of the board / cable.

[Audronic]

Hi @darkage and @Pat the Cat.

Problem Sorted  ?
The load on the IR Reciever was to low (Original Design) which was 670 Ohms.
Now modified to 2.7K ohms as per Pavel Ruzicka's Circuit.
I have changed all 5 Resistors to this standard.

Thanks for all your help.
Ray