Arduino noob trying to connect an SRF02 Ultrasonic Distance Sensor

Projects General Guidance
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I'm an Arduino noob taking my first stumbling steps outside my SparkFun beginner's kit. I purchased an SFR02 distance sensor and think I'm having problems with physically connecting it properly.

See attached image.

I've been following this tutorial: http://arduino.cc/en/Tutorial/SFRRangerReader - but I didn't have a capacitor. Running that Arduino code yields no result whatsoever.

I also found this awesome framework http://www.grapelabs.org/arduino/libraries/srf02-ultrasonic-distance-sensor and when running that code, it prints out "0" two times and then "65279" on every loop.

All suggestions are welcome!

SFR02.jpg
SFR02.jpg700Ă—525 74.3 KB

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Related to this: what's the proper way of connecting a board with "holes" like the SFR02 board? I'd like to avoid soldering since I'm prototyping, but still ensure good connections.

1 Like
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That tutorial doesn't show any pull up resistors on the I2C lines.
Use something around 4k7 ohms.

I have four of these devices on a single bus working without problems.

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AWOL:
That tutorial doesn't show any pull up resistors on the I2C lines.
Use something around 4k7 ohms.

As you see in my image, I'm using two 10k resistors (all I had laying around). Too much?

5

I can't see from the image how they're connected.
10k pull up seems a bit high, but I don't really see that it won't work.

I solder pin headers to devices, then plug them into ribbon cable headers.
I have easily 60cm of 10 way cable with four IDC headers at 10cm spacing.

6

AWOL:
I solder pin headers to devices, then plug them into ribbon cable headers.

Thanks, problem now solved! I soldered the SRF02 board to a 4-way ribbon cable header, swapped the resistors to 6k, and voilĂ : distance meter is working.

AWOL:
I have easily 60cm of 10 way cable with four IDC headers at 10cm spacing.

Hmm not sure I get this bit, please elaborate. 10cm spacing?

7

I have a 60cm length of ribbon cable. There's an IDC connector at one end to plug into my processor board, and the other end of the cable has four IDCs at 10cm spacing. These are connected to my four SRF02s.
The pull ups are on the main board.

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AWOL:
There's an IDC connector at one end to plug into my processor board, and the other end of the cable has four IDCs at 10cm spacing. These are connected to my four SRF02s.

Ah, got it: you can connect multiple SRF02's serially. Thanks!

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you can connect multiple SRF02's serially

I think the devices support up to sixteen I2C addresses, but my CD-sized robot hasn't got enough room or battery capacity for that many!