IR detection
Hello,
I purchased a pair of infrared emitter/detector at Radio Shack (sku2760142). The emitter works fine, since the Panasonic detector that came with the Boe-Bot pick it up. However the detector has only 2 leads and I tried unsuccesfully to pick up a signal using a resistor at the anode going to one of the I/O line and another resistor going to +5V to power it up. Is this a case where I need a DAC to read object/distance detection. Anyone has a schematic that would work with this duo. I searched the forum and did not find information relating to this. Finally if anyone understand the difference between the 2 detectors i would like to know more. I would appreciate any information.
thanks
Jo
I purchased a pair of infrared emitter/detector at Radio Shack (sku2760142). The emitter works fine, since the Panasonic detector that came with the Boe-Bot pick it up. However the detector has only 2 leads and I tried unsuccesfully to pick up a signal using a resistor at the anode going to one of the I/O line and another resistor going to +5V to power it up. Is this a case where I need a DAC to read object/distance detection. Anyone has a schematic that would work with this duo. I searched the forum and did not find information relating to this. Finally if anyone understand the difference between the 2 detectors i would like to know more. I would appreciate any information.
thanks
Jo
Comments
What you need is a stabilizer to +5V or +0V...
I would recommend a MM74HC14 but it is also an inverter and not easy to handle unless you invert all your binary data for IR...
Exable:
IF (detectorL =· 1) THEN .......··························································································· Having an inverter will be like this:·······························
IF (detectorL = 0) THEN .......
Stabilizer must exist but I don't know which one can serve you best...(and not being inverters)
Regards, Provas, GREECE
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--Be Good. Be Bad. Be Provas--
I don't know anything about the Boe-Bot, but I am using a reflective IR pickup for an SX project.
It sounds like you are pretty close to having it work.· I simply connected the collector of the phototransistor (they might call it the cathode on your part) to the i/o port, and pulled up the i/o port pin to 5V·with a·4.7k resistor (I may just use the internal pull-up on the port pin).· Then I connected the emitter (they might call it the anode) of the phototransistor to ground.· When enough IR light hits the detector it will pull·the input·low.
As mentioned by Provas, it would be nice to have a buffer to provide a clean 0/5v signal to the i/o port.· If the Boe-Bot has the option, configure this input pin as a·schmit trigger input.··An external schmit trigger like the 74hc14 will work, but is an extra part to get in the way.· The fact that it inverts the signal doesn't really matter, and might actually be nice.· When light hits the detector (pulling the 7414 input low) the port pin will be a "1".
Have fun,
Jim