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Trying to build a simple RF remote control

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Fibericon

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Trying to build a simple infrared remote control

First, I'm new at electronics, just thought I should get that out of the way. I picked up this RF receiver and transmitter (not soldered to any circuit board) today, and I want to make a simple remote controller out of them. I really only need to send the state of a switch (on and off). The only information on the label was "M1031 - 40KHZ - 10mm". I've never done a project like this before, and I'd appreciate if someone could link me a circuit diagram. The simpler the better, I'm not trying to do anything complex here. Thanks in advance.

EDIT: Sorry about the self bump, just realized I could edit my original post. My Chinese isn't very good, so I initially thought it said it was RF. It's actually infrared.

EDIT: Wrong again, it's ultrasound. My Chinese is terrible.
 
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Fibericon

New Member
In my research I found something that might be important to note. The transmitter and receiver I have only have 2 pins each. Unless I'm screwing up somewhere in my search, it seems that most have more pins than this. One pin has a black circle around the base and one doesn't. What is the significance of this?
 

audioguru

Well-Known Member
Most Helpful Member
In my research I found something that might be important to note. The transmitter and receiver I have only have 2 pins each. Unless I'm screwing up somewhere in my search, it seems that most have more pins than this. One pin has a black circle around the base and one doesn't. What is the significance of this?
An ultrasonic transducer is a piezo speaker (tweeter). It has only two pins. The transmitter needs to be driven from an oscillator and the receiver needs an amplifier and detector circuit.
 

audioguru

Well-Known Member
Most Helpful Member
The circuit for the receiver is completely wrong:
1) The lousy old 741 opamp performs poorly above 9kHz. The ultrasonic frequency is 40kHz.
2) The first opamp is inverting with an input impedance of only 330 ohms but the piezo transducer needs a load no less than 10k ohms. The opamp should be non-inverting with a 10k to 20k input impedance.
3) The load of 330 ohms on the output of the first opamp is not needed and its value is much too low (it is almost a dead short).
4) The second opamp has no DC bias voltage on its + input. Its - input is biased but should be connected as negative feedback instead.
 

MikeMl

Well-Known Member
Most Helpful Member
Other than that, what dont you like about it? :D
 
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