Working with distance sensor

r.lopes32 · Joined: 09 Sep 2010 Posts: 1 Location: Brazil

Hi Guys,

I am using a distance sensor in my project and I need a little help on code.

Basically, the sensor works with two pins (PIN_1 trigger and PIN_2: Echo). when I put PIN_1 in logic level 1 the sensor sends a signal in a waveform when the wave find an object it will return and the PIN_2 echo will be logic level 1.

The question is: How can I measure the time between the trigger PIN_1 and receive the signal back on PIN_2

Data Project: PIC 16F877A, clock 4Mhz

Thanks in advanced,
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Rodrigo Lopes

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

You should admit that you're using the Parallax Ping sensor or the
Devantech SRF-04, or something similar.

You can use the CCS delay routines, delay_us() or delay_ms() to create
the trigger pulse. Read the sensor documentation to see what is the
required length of the trigger pulse.

Then you can use the Pulsin() routine in the following thread to read
the duration of the echo pulse.
http://www.ccsinfo.com/forum/viewtopic.php?t=42353&highlight=pulsin