I am setting up an Arduino Uno with a sonar sensor from Maxbotix (http://www.maxbotix.com/Ultrasonic_Sensors/MB7360.htm). The sensor will be powered directly from the Arduino (5V).

The sensor needs to be about 5 metres from where the Arduino will be located. Will using a wire/cable this long work okay as is? I plan to use a speaker cable or similar. I read the question below, but at no point does the author define what a long cable is...

Long three cables connection: can I use an audio stereo cable?

Am I okay up to 5, 10, 20 metres? What is a "long" cable in this context?

  • 1
    \$\begingroup\$ If you don't define what you mean by "work okay" and "speaker wire or similar" then it is impossible to define what "long" means. Every additional inch of cable has some affect on the signal, and we can't fill in the details that you have left out in order to arrive at a definitive answer. \$\endgroup\$ – Joe Hass Dec 10 '13 at 12:16

Per the datasheet, the MB7360 has an RS232 interface, unlike the analog interface in the question you linked. You should be able to easily run 20 meters or more with unshielded cable.

  • \$\begingroup\$ Thanks! I took you advice and tried with a 20m cable and it works fine. It gives me a lot of extra flexibility over where I place the Arduino. \$\endgroup\$ – That Guy Jan 10 '14 at 8:15

That webpage quotes the average current used as 29ma, which is low enough that it's unlikely to have problems. However, if there are peaks in the current usage, the voltage may drop due to the resistance of a long wire. If you get this problem a small electrolytic cap across the power pins of the device at the far end of the cable should help.

  • \$\begingroup\$ Thanks, great suggestion. I was able to get it working fine with a shielded cable 20m long. \$\endgroup\$ – That Guy Jan 10 '14 at 8:16

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