Sonar codebug - ultrasonic ranger

[mikerr]

Use a HC-SR04 ultrasonic sensor with the codebug to detect / measure distance:

- leg 0 set as input, with pullups disabled
- pull down resisitor across leg 0 and ground

Code sends a 10ms pulse, and listens for it's echo.
"distance" is measured by the delay of the echo in ms


https://www.youtube.com/watch?v=Ps05LsqzzxE



Distance value is around 1/3 the measurement in cm
e.g. distance value of 5 is 15cm

The sensor is good to around 2 meters

http://www.codebug.org.uk/explore/codeb ... onar-eyes/

[mikerr]

I should add that the sensor only works reliably at 5v
it gets jumpy and inaccurate down to 3.5 and not at all at 3v.

[Gyuri]

How much resistance?

[mikerr]

Anything around 10k is ok