SparkFun Forums

[Aggrav8d]

Hi, gang!

I've got a Razor 9DOF IMU connected to a Duemilanova atmega328 through pins 2 and 3.

The Duemilanova atmega328 is connected to a PC through the USB.

I'm trying to talk to the IMU with the PC so I can figure out what the IMU is actually doing. I hope to help improve documentation for other developers doing exactly the same thing.

I've been trying to use NewSoftSerial without much success.

Can one of you delightful, patient experts please tell me how to do what I'm trying to do?

Thank you!

[SFE-Mike]

If you can't get newsoftserial to work, you can split the Arduino's serial port between the 9DOF and your computer, but you'll only be able to get data from the 9DOF, not send anything to it.

To do this, temporarily hook your computer directly to the 9DOF (using a 3.3V FTDI Basic Breakout or similar). Then you can use the menu option CTRL-Z to put it into "autosend mode". It will then output all 9 readings repeatedly when it powers up.

Then you can hook up the TX of the 9DOF to the RX on the Arduino, and use the TX of the Arduino to pipe the output of the 9DOF to the serial monitor on your computer.

You'll need a simple program on the Arduino to read characters from the serial port, and output the same characters to the serial port.

Remember that you'll have to disconnect the 9DOF from the Arduino to program the Arduino.

(Then again, if you can hook the 9DOF directly to your computer to send the CTRL-Z command, you could bypass the Arduino entirely...)

[Aggrav8d]

Should I be at all concerned about the voltage difference between the arduino (5v) and the sensor (3.3v)? I'm waiting for a logic step-down (is that the term?) and I wonder if I'm being paranoid.

[coyote20000]

Should I be at all concerned about the voltage difference between the arduino (5v) and the sensor (3.3v)? I'm waiting for a logic step-down (is that the term?) and I wonder if I'm being paranoid.

See the 5th comment in this thread.
viewtopic.php?f=14&t=22619

it appears that a 5V arduino will read a 3.3V signal. Going the other way, you should use a voltage divider.

Dave