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Drawing schematics? Answered

This is Mousey the Junkbot's schematic...does he even have a third wheel?

I would be very much obliged to anybody who can anybody draw this schematic out:



Best Answer 6 years ago

Worked out the circuit wiring for you two ways. The 3d wheel could be a swinging one or roller ball


your circuit works...right?

To design something means to put it to paper from a minds eye = ie gray cells.
As said I would design it differently but have not done so as yet.
After a design it needs building and testing before it can be said To Work.

Sorry don't have an answer, but thinking about it, here is a first cut at it.
It should work better then the drawing, but I don't have information on the


Of course, what is their dark output ?
What is their normal room light output ?
What is their output when completely light saturated ?
What is their spectral response ?
I assume the respond faster then 5 sec.
Then it may be possible to predict response.

Take a quick look at the original site for Mousey. You'll see that they are reusing some of the parts from the donor mouse, namely the infrared emitters as listed in the bill of materials - not quite halfway down the page - and one of the touch switches as well. The FAQ (and the site overall) will clear up quite a bit of the questions you might have.


I think infrared emitters is/are what you are calling the IR eyes.
I consider emitters <=> IR light sources which eyes are not.
BTW my browser ( Firefox ) cannot follow your second link.

Anyway, now I don't expect to get any info on the "eyes" except they were
made to detect mouse mechanism motion with no halfway response like
a Schmidt trigger output transition.

Interesting, the second link gives me a fatal error message. I went back to the first link and scrolled down to the FAQ link and went right there. Must be the PHP coding. Anyway... if you get there and look where I stated, right under the parts list states how the emitters are turned into detectors. From the FAQ:

"Q: How come you're supposed to use the Infrared emitters from the mouse as Mousey's light-sensitive eyes? Why not the IR detectors?
A: The reason why we use the emitters and not the detectors from the mouse encoder wheels is that the IR detectors are designed to only turn on and off at a specific light level. The emitters, although they were designed to SEND infrared signals, will also respond to a wide spectrum of incoming light levels (just as any Light Emitting Diode, while it's designed to emit light, is also sensitive to light). For the IR emitters, we do a number of things to make that light response more sensitive. First, we connect the Gain pins (1 and 8) on our LM386 Op-Amp chip, which boosts the signal strength, then we use "reverse biasing" (switching the positive and negative leads on the emitters) to pump up the signal even more, and then we add our sensitivity booster sub-circuit, which gives us another gain. All of this turns the lowly mouse IR emitters into reasonably light-sensitive robot eyes."

The rest of the FAQ is a good read also.


O.K. we did reverse bias LEDs as detectors with the early glass red units.

This is a fairly sophisticated technology for beginners who need help seeing a
schematic from component wiring and yes gain is at the highest LM386 gain of
200 with pins 1 & 8 joined.


When you say "I don't want to use this ic" - do you mean "I would be very much obliged to anybody who can anybody draw a different schematic that doesn't have an IC in it"?

LM386 schematic


You awarded him a best answer, thanks - the system work better when people use that button.
But I think that while "sufficient" is adequate, you could have been more positive? - he's good.


Good use of language, nowt wrong with that.
Next time you could sound smart and kind.


To say something more positive than "sufficient" in future.



I am happy that you could do so for him. I just wanted to point out that the pictorial at the top of the page does not have the inputs shorted together. They are fed from the individual positive legs of the "sensors". Clicking the boxed i shows the pic without the textbox and it is clear there just as it is clear in the link I posted earlier. Just sayin'...

Thanks for all the help you give in the Answers section. Always good to read yours.

Hope this clears things up,

Ohh.... Finally spotted my error, Thanks for alerting a old blind eye :-o

Why do you call me 'blinky'?

Can I use LM358?

blinky, affectionately short for blinkyblinky :-)
Was I inappropriate ?

No, because the 358 ( second pic ) has No built in gain. It is open loop which
is very high 100 Volts per milli volt or 100,000 to one, it will go rail to rail at the slightest variation of light.

See the ( first pic ) of the LM386 to compare the
output, gain and input structures.

Original Poster. A fairly standard web abbreviation

Iceng, you wrote a few comments I can't see...

what happened?

Reworded and deleted mistyping errors.

One small revision to your schematic, iceng. Break the connection between pins 2 and 3 of the IC. As drawn, both pins are always at the same potential and the IC will either never change state or oscillate wildly, neither of which was intended, I believe.

You can find a clear, large, original at Mousey's site.

Also, when substituting IC's, you must verify similar output capacity. Some of those you listed look like they as capable as the LM386. Some of the others look like they are a bit underpowered. I don't have personal experience with most of them, so i will defer to your experience with them.


To blinkyblinky - what is the aversion to using the LM386? It is cheap enough to go buy at the local "electronics" store (Radio Shack et al) that it precludes any reason not to use it.

Has the OP altered the question??

Yes it has a 3rd wheel not powered so not shown on the diagram.