Wireless FlexiForce Sensor

Hello All,

I’m pretty new to the forums, but I used the search function to find out all I could about this subject. After reading up on all I could, I’ve concluded that my project is feasible, but difficult for me. Unfortunately, I’m currently entering my 3rd year studying Mechanical Engineering, and my electronics knowledge is frighteningly inadequate :~ . Therefore, I’ve come to you guys to see if I could have someone help me figure out how to make sense of this stuff.

OBJECTIVE:
A device comprised of two components which interact wirelessly: (1) data-collecting instrumentation and (2) an output monitor. The data will be generated from the force of a compression spring, varying with time in discrete steps, pressing against a FlexiForce #A301 (http://www.tekscan.com/pdf/A301-force-sensor.pdf) force transducer. The output monitor will display a number proportional to the amount of force the FlexiForce sensor is subjected to; that is to say, how much the spring is compressed. The data-collecting component will transmit data to a receiver located on the output monitor via XBee radios (using Zigbee protocol). Both the sensor and output components will be able to be powered by AAA batteries.

RESEARCH:

-I’ve found some basic DIY tutorials (namely, the above), and I’ve begun to understand a little of how to condition the signal.
-The FlexiForce Starter Kit (http://www.tekscan.com/store/flexiforce-sensors/starter-kit.html) seems to have all the components I need to start creating a circuit. I know I’ll need to solder it all together, so I’ll be practicing that on spare bits of wire before I do anything with the real components.
-Since I will be using XBee modules to communicate data, I will need the Arduino Wireless Shield for processing.
-Force output from the sensor will vary anywhere between 10N and 50N.
-Transmission times should be as close to 0.01 seconds as possible.
-Battery Life Information: http://www.faludi.com/projects/arduino-and-xbee-battery-test-results/

EXPERIENCE:
Limited experience with robotics in high school, about 3 years ago.
I do have a solid background C/C++, MATLAB, and LabView, so the programming aspect should not be the main issue.

QUESTIONS:

  1. So, and this may seem a bit elementary, should the “V-OUT” from the proposed circuit diagram from FlexiForce should go straight into a pin on the Arduino board?
  2. Is there any additional circuitry needed to connect a XBee module to the Arduino Wireless Shield?
  3. On the receiving end of things, what does the XBee receiver actually output to the other Arduino Wireless Shield?
  4. Is a AAA, or even a AA, battery powered configuration even feasible? Is 9V necessary?
  5. I see where the positive and negative voltages need to go into the FlexiForce and associated signal conditioning circuitry (the op-amp), but where - and how - do I get the right voltages in from the battery? Simply resistors? And would the Arduino Wireless Shield get enough power from this battery?

Let me know if I need to provide any additional information in order to clarify anything. Thanks so much in advance!

-Transmission times should be as close to 0.01 seconds as possible.

Why? If the data takes less time than that to transmit, what do you want to send to fill the extra time?

  1. So, and this may seem a bit elementary, should the "V-OUT" from the proposed circuit diagram from FlexiForce should go straight into a pin on the Arduino board?

The one that you say that you still need to design?

  1. Is there any additional circuitry needed to connect a XBee module to the Arduino Wireless Shield?

No.

  1. On the receiving end of things, what does the XBee receiver actually output to the other Arduino Wireless Shield?

Exactly what you sent on the sending end.

  1. Is a AAA, or even a AA, battery powered configuration even feasible? Is 9V necessary?

Yes, AAA batteries (not just one) or AA batteries can be used. Leave the 9V battery in the smoke detector.