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Topic: tsop1140 sensitivity (Read 2049 times) previous topic - next topic

_kuroo

i have a tsop1140. how do i decrease it's sensitivity cause it seems to be receiving 40khz signals right through walls!!!!!!!!!!!!!!!!!!!!?!
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MarkT

signals or just noise?  The chip has AGC so it will pick up the noise-floor if no real signal is present I think.  Certainly you don't have control of sensitivity electronically.
[ I won't respond to messages, use the forum please ]

Grumpy_Mike

Have you got the 100R series resistor in the supply and at least 4u7 across the supply like it shows in the data sheet.
You need them.

_kuroo

#3
Aug 01, 2012, 05:39 am Last Edit: Aug 01, 2012, 05:42 am by _kuroo Reason: 1
im trying to block 40khz signals from a remote but yeah it still sees through the ball at a really far distance.

is that the application circuit? what does it do?
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_kuroo

Can someone tell me what uC is on the circuit as well?

http://www.vishay.com/docs/82006/tsop11xx.pdf
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Grumpy_Mike

It decouples the supply voltage and makes it look like a low impedance so the circuit works correctly.

The uC is not anything special just a generic indication.

_kuroo

I still don't understand. uC is where the 3 wires come together? and where is the signal being outputted?
Dip your feet in gasoline, walk on lava

Grumpy_Mike


_kuroo

and the arrow that points downwards with Vo, whats that?
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_kuroo

im using a 0.1uf ceramic capacitor. is that ok?
Dip your feet in gasoline, walk on lava

Grumpy_Mike

Quote
the arrow that points downwards with Vo,

It indicates the voltage is measured between the output with reference to the ground.

Quote
im using a 0.1uf ceramic capacitor. is that ok?

No it is not.
The data sheet says 4u7 and it means it.

When I worked on set top boxes one team had a smaller capacitor and had all sorts of trouble with field returns until they changed it to the proper value.

_kuroo

I'm not sure what a '4u7' looks like =S , aside from it being a capacitor. not even sure what type.

if that circuit is to decouple the power supply, isnt it only protecting it against power surges? how does that help with the issue of the ir signal being seen through walls?

I also realised that when I was successfully able to block the signal,it wouldnt read no matter what until I exposed it to an opening in my shielding and after that it locks onto the signal of the ball and it can go through my shielding. Any suggestions?
Dip your feet in gasoline, walk on lava

Grumpy_Mike

#12
Aug 02, 2012, 03:06 pm Last Edit: Aug 02, 2012, 03:09 pm by Grumpy_Mike Reason: 1
Quote
I'm not sure what a '4u7' looks like

A cylinder about 1cm in diameter and 3cm long. It will be an electrolitic. There are other shapes as well.
Here are some:-
http://uk.farnell.com/jsp/search/browse.jsp?N=2031+202457+110110283+110119850&Ntk=gensearch&Ntt=capacitor&Ntx=mode+matchallpartial&No=0&getResults=true&appliedparametrics=true&locale=en_UK&divisionLocale=en_UK&catalogId=&skipManufacturer=false&skipParametricAttributeId=&prevNValues=2031+202457+110110283&mm=1000002||,1001880||,&filtersHidden=false&appliedHidden=false&autoApply=true&originalQueryURL=%2Fjsp%2Fsearch%2Fbrowse.jsp%3FN%3D2031%2B202457%26Ntk%3Dgensearch%26Ntt%3Dcapacitor%26Ntx%3Dmode%2Bmatchallpartial%26No%3D0%26getResults%3Dtrue%26appliedparametrics%3Dtrue%26locale%3Den_UK%26divisionLocale%3Den_UK%26catalogId%3D%26skipManufacturer%3Dfalse%26skipParametricAttributeId%3D%26prevNValues%3D2031%2B202457

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how does that help with the issue of the ir signal being seen through walls?

You can't read an IR signal through walls. What tests have you done that make you think you have? I suspect your system is oscillating due to lack of decoupling.

Quote
if that circuit is to decouple the power supply, isnt it only protecting it against power surges

It is rather the same thing.

Quote
I also realised that when I was successfully able to block the signal,it wouldnt read no matter what until I exposed it to an opening in my shielding and after that it locks onto the signal of the ball and it can go through my shielding

This is the first you have mentioned of this.

Quote
Any suggestions?

Stop keeping things secret, tell us exactly what you are doing and exactly what you have wired up to what.

_kuroo

infared ball:
http://www.elekit.co.jp/material/english_product_html/RCJ-05.php

its for a competition. ive seen playing around with this thing everyday.

i just played around it again and now it seems like my shielding is ineffective.

Dip your feet in gasoline, walk on lava

_kuroo

#14
Aug 03, 2012, 08:42 am Last Edit: Aug 03, 2012, 08:44 am by _kuroo Reason: 1
and i've got that circuit because i couldnt be bothered putting it into the arduino.

the shieldings made of foil, wrapped around with electrical tape, wrapped in duct tape, then wrapped in foil again and then another layer of electrical tape. im not sure if that's sufficient enough >.<

btw thanks for the help soooo much.
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