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Help!!

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Nigel Goodwin

Super Moderator
Most Helpful Member
Does someone have an explanation? :confused:

Yes, don't connect a DMM to the output :D

It's completely unsuitable for what you're trying to do, and the IR IC won't work properly unless you've got it connected correctly, they are quite fussy about their connections (decoupling and short connections). There are examples in my PIC IR tutorial that work fine, built on veroboard - breadboard probably isn't a good idea, assuming that's what you're doing.
 

4pyros

Well-Known Member
Most Helpful Member
Sounds to me like you have your receiver hard wired and the wiring is picking up RF. Even just your meter leads can do this if the phone is close enough.
 

N.Carsane

New Member
It's been like a few months since i've used PIC's , those commands seem too advanced for me even though i got full marks for the PIC coursework. But i just want to use the IR receiver to turn something on and off, any ideas for this without using too much complex stuff like PIC's. I don't mind transistors, or comparators (op amps) and other simple applications.

Also i've seen people use transistors to create logic gates, has anyone one got any schematic for a NOT gate and other logic IC's replacement by transistors?
 

N.Carsane

New Member
Sounds to me like you have your receiver hard wired and the wiring is picking up RF. Even just your meter leads can do this if the phone is close enough.

So if i don't connect the IR receiver to the leads, would i still get the signal form the phone if it's close to the leads?
 

Reloadron

Well-Known Member
Most Helpful Member
Would be cool if you had a scope to actually see the pulse trains from an IR transmitter. Oh well, at least what you seem to have is an IR detector. I don't understand why the meter does what it does with the phone so I'll call it magic. I also tend to believe the meter may be picking up some RF interference, I can't think of much else. :)

Ron
 
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4pyros

Well-Known Member
Most Helpful Member
Put you phone close to the meter leads and see if you get any voltage.
 

N.Carsane

New Member
Put you phone close to the meter leads and see if you get any voltage.

I tried it with the same distance but no spikes in AC reading so... so that's not the case, it is either the receiver or the wires picking up the signal i'd assume...
 

Reloadron

Well-Known Member
Most Helpful Member
Also i've seen people use transistors to create logic gates, has anyone one got any schematic for a NOT gate and other logic IC's replacement by transistors?

Since there are so many I suggest you just do a Google of "Transistor Logic Gate Schematics" and you will get pages and pages of drawings and images. I saw a few good pdf papers on the subject also. Doing it that way you will see all sorts of variations on all sorts of TTL (Transistor Transistor Logic). Heck we could likely fill another complete thread on that subject. :)

Ron
 

N.Carsane

New Member
Since there are so many I suggest you just do a Google of "Transistor Logic Gate Schematics" and you will get pages and pages of drawings and images. I saw a few good pdf papers on the subject also. Doing it that way you will see all sorts of variations on all sorts of TTL (Transistor Transistor Logic). Heck we could likely fill another complete thread on that subject. :)

Ron

I have googled it but none so far have showed the switching thresholds and also some use the 2N222 and some use the BC547 transistor, which is better and why?
 

N.Carsane

New Member
It doesn't matter what transistor you use (within reason), it's a question of what you have, if you want NPN or PNP, or what's cheap.

I want something with a small linear region and since i've worked with NPN's and not PNP's i'd prefer NPN's. And something not far expensive but costworthy, sounds like a lot to ask for though...
 

Reloadron

Well-Known Member
Most Helpful Member
Real quick one problem I see starting to happen in this thread is we are really drifting. While the thread topic (title or name) doesn't say much, "Help" is not a good title, the thread is really drifting off target. We went from an IR receiver to logic gates and transistors. Things might run a lot better if a new thread was created and titled something like "Logic Gates" so members with good experience and gate knowledge could contribute. I am not attempting to "memberate" here, merely pointing out that in my humble opinion we are drifting off the target.

Ron
 

4pyros

Well-Known Member
Most Helpful Member
I want something with a small linear region and since i've worked with NPN's and not PNP's i'd prefer NPN's. And something not far expensive but costworthy, sounds like a lot to ask for though...
ya why do you want this?
 
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