halltech
Newbie level 2
![Newbie level 2](/styles/images/ranks/alevel2.gif)
Hi! I've been having a bit of trouble with ringing on a input signal to a uc.
The setup is as follows:
The circuit is just basically converts the +12V signal to a 5v level, the input signal is from an infrared sensor (Telemecanique Osiconcept) which is connected to the uc via approx 15m of unscreened cable.
During testing I have the sensor and cable around on the floor and when I turn the lights on in the office I get a high frequency ringing on the signal line with then triggers the uc unintentionally.
As the infrared sensor is used as control signal, I don't want to have false triggers caused by noise.
The uc and other circuity is all power by a 12 battery with the 5V supply a switching regulator running at 250khz
Any help would be appreciated.
Cheers
Cameron
Attached is the trigger circuit schematic and a pic of the oscilloscope output
![circuit.png circuit.png](https://www.edaboard.com/data/attachments/28/28107-a52d464d5b7eb5c7ae326e64a08f3a54.jpg)
![IMG_20130122_113253.jpg IMG_20130122_113253.jpg](https://www.edaboard.com/data/attachments/28/28108-740dc033526b6783bb83e172de11487d.jpg)
The setup is as follows:
The circuit is just basically converts the +12V signal to a 5v level, the input signal is from an infrared sensor (Telemecanique Osiconcept) which is connected to the uc via approx 15m of unscreened cable.
During testing I have the sensor and cable around on the floor and when I turn the lights on in the office I get a high frequency ringing on the signal line with then triggers the uc unintentionally.
As the infrared sensor is used as control signal, I don't want to have false triggers caused by noise.
The uc and other circuity is all power by a 12 battery with the 5V supply a switching regulator running at 250khz
Any help would be appreciated.
Cheers
Cameron
Attached is the trigger circuit schematic and a pic of the oscilloscope output
![circuit.png circuit.png](https://www.edaboard.com/data/attachments/28/28107-a52d464d5b7eb5c7ae326e64a08f3a54.jpg)
![IMG_20130122_113253.jpg IMG_20130122_113253.jpg](https://www.edaboard.com/data/attachments/28/28108-740dc033526b6783bb83e172de11487d.jpg)