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IR receiver module interpretation

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Team PSU

New Member
So I did a couple quick searches for the information I'm looking for and it appears that many people here are not fans of the Oopic-R microcontrollers? I do not intend to defend/promote the disuse/use of these. However, we are using an Oopic-R for our senior project. Thus far it is controlling a handful of servos and other inputs but I need some assistance recognizing a signal at one of the I/O lines on the Oopic.

We are making a knock-off target acquisition system. We have five IR receiver modules scanning for the presence of a matching IR signal. Depending on what receiver module sees the IR source, our programming code will tell a servo to rotate in a specific direction to line up the cannon of our project.

We have 5, TSOP7000 IR receiver modules. When the correct IR signal is present in front of one of the modules, the receiver signal goes from a logic 1 (+5v) to a logic 0. However, instead of staying at logic 0, the signal goes back to high when the pulsed IR signal goes high. Therefore, the receiver signal is a square wave around 2kHz, 50% duty cycle.

I need assistance on how to get the Oopic-R to notice the signal change and then execute the next code (i.e. rotate to the right, and wait for next receiver module to become active).

Thank you for any help in advance, and I will check this often!
 

Gayan Soyza

Active Member
You need to learn much about IR before doing your project.

IR receiver detects its incoming signal from the incoming signals burst length.
Not from the individual pulse (marks & spaces) in the incoming frequency.

There are some minimum requirements that the transmitter should follow to receive the incoming signal from the receiver. These timing must match according to the data sheet. Specially the “Burst Length”.

If the burst length is accepted by the receiver it will output low from the receiver. If no burst it will make output from the receiver. You need to poll these conditions by your micro.

So you need to implement a protocol by your self or you can take a standard IR protocol
Which many consumer products use ex: RC5X, SIRC, NEC etc……..to communicate with your TX & RX.

The receiver you introduced (TSOP7000) its frequency is out of standard frequency range.So better develop your own protocol to that receiver module.
 
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Team PSU

New Member
Thank you for the reply. However, I know the signal being pulsed by the IR LEDs is matched to the IR receiver module.

Are you saying that the receiver module is supposed to output a constant logic 0 when the correct IR signal is present?

How can I set up the Oopic-R to recognize this change from +5 to 0?
 

Team PSU

New Member
Actually, after further testing and investigation... The receiver module isnt supposed to go from logic high to logic low when the signal is present. It is supposed to output in the same form as it receives.
Therefore, I just hooked up a voltmeter to the output line of the receiver modules. When the sensor is not active, it outputs 4.83 volts, when it sees a correct signal it outputs about 2.5 volts, depending on the range between emitter and receiver.

Can the Oopic be programmed to read these voltage differences?
 

Team PSU

New Member
So if the oA2DX Object from the Oopic website will not work, how can we make the Oopic realize the present signal?

Where at in your tutorials should I be looking at?

I have not dealt with microprocessors before.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
So if the oA2DX Object from the Oopic website will not work, how can we make the Oopic realize the present signal?

Where at in your tutorials should I be looking at?
The IR one shows how to receive and transmit the Sony SIRC's system, a common remote control type.

Can't help you with the Oopic, it's an obscure and limited device that isn't very popular.
 
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