Ultrasonic Range Finder (SRF08)

[elaine84]

Anyone here knows how the SRF08 works in the way of capturing ranges to a 8501-based microcontroller? I'm in the middle of my project but I do not know how to check the status of the range finder. It can return ranges in cm but I am not sure whether it transfer the range in whole number only or with decimal point?

In other way of asking, how accurate the range finder can capture? How to test whether it is working before writing the I2C bus program?

Th range finder seems spoilt, I found out that the SCL and SDA line are shorted with the ground when I tested it with my mulitmeter.
My I2C program works for I2C Serial EEPROM. It should be the same for the range finder right?

Please help me with it... Thanx alot!!!

 

[Joel Rainville]

The range finder seems spoilt, I found out that the SCL and SDA line are shorted with the ground when I tested it with my mulitmeter.

If it is indeed the case, you found the cause of your problems. But are you a 100% sure? Both pins shorted to ground? You tested this while the SRF08 was powered, right?

 

[elaine84]

Nope... I tested it with no power supply and the internal pins are shorted to ground also. However, my supervisor has pass me a SRF10 which has almost the same function today and it works well. But I do not know whether its giving me the correct value.

Does anyone know how should I read the value in hex which is received by the microcontroller? I have set the ranging mode in cm.

I also cannot confirm that my sending sequence are correct. Do I need to send the location for command register first then stop the I2C and then send the ranging mode or I can send this two instruction straight with this two things? There are no resources that tells about this and thats why I am not sure of many things. But I confirm that my I2C protocol is working.

 

[elaine84]

Anyone here used the SRF08 before? My program is working correctly but the range finder seems unstable as the results obtain mostly wrong. I need the range finder to be able to measure a distance of 2m but till now still could not get that. I did not do any setting of the analogue gain and range register, so it should be able to sense up to 11m with a gain of 1025.

Same problem happens when i use a SRF10. I oso tried with setting the analogue gain lower but the reading are still the same...

Hope to get some help from here.... Thanx alot.