LDC1614EVM: LDC1614EVM + Arduino

Hello Alexander,
Does every register read 0's? or just the DATA_MSB_CHx and DATA_LSB_CHx values? Also note, if the ground connection on the EVM is not connected, then it could be at a different voltage potential than your micro which can pose a problem for communication on the I2C bus. After connecting the grounds, I would also verify on an oscilloscope that your I2C communication between the LDC and your micro look good. Check the SCL and SDA pins for the proper I2C signals and programming sequence outlined in the datasheet on page 17. Also look for signal integrity and timing issues.
Regards,
Luke

Dear Mr. Luke Lapointe
Thank you for responding to my enquiry and will reply as soon as I meet with a friend who happens to be a programmer concerning your questions.
As a retired physics and mathematics teacher with the Boston Public Schools, I have been very interested as of late in constructing projects in the area of physics education. I am not an engineer or computer programmer (learning C++),but have been teaching myself how to code for the Arduino platform and in Processing (the graphing software). The FDC2214EVM capacitive sensor is a great interest to me, but can’t tell if the hardware would apply to my project.
As a background note, I have built several projects using the Arduino Uno and the PixyCam Camera (CMUCam5) to capture x-y-z coordinates; but unfortunately the Pixy’s frame rate is 50 fps.
Background on project:
I want to collide two 6mm BB (plastic, metal etc ) pellets, and obtain their x-y-z coordinates for one second at the fasted fps possible, and insert the data into an Array to be scattered plotted in Processing. The event will be triggered by the BB Pellet passing through a velocity chronometer (presently connected to Arduino Uno my Mac BookPro). Again, I’m not an engineer but kindly request information or guidance of the feasibility in using the FDC2214EVM for my measurements ( I have been considering and tinkering with the LDC1614EVM).
The collision chamber would consist of three perpendicular copper plates, where each plate will provide displacement data from its surface. The “ raw data” can be later linearized. I have also purchased a PC in order to run your “ Sensing Solution EVM GUI “ (v1.9.1).
Questions.
1. Will the FDC2214EVM detect linear displacement of my 6mm BB pellet (raw data output)? The collision will be inside a one meter cube chamber.

I want to thank you very much for your time an effort in steering me in the right direction, and for any resources which will educate me.
Sincerely,
Alexander Luis

Hello Alexander,

This application sounds very challenging especially considering the 1m^3 chamber and the 6mm plastic BB. The response from the plastic pellet will likely be very small if noticeable at all from the noise floor. Also note, the faster you sample the less resolution you get. I would say that unless you can increase the size of the pellet or make the chamber much smaller it will be very difficult to accurately sense the location. If you already have the setup you can verify the response you get by using the FDC2214EVM and the Sensing Solutions GUI to stream the data. 

Regards,

Luke

Dear Luke,

Thank you again for responding. I will change the BB pellet to a 4.5 mm copper pellet BB.

I have also decided to purchased a PC in order to run your GUI (save my MacBook Pro), in addition  to purchasing your LDCCOILEVM.

The following LDCCOILEVM spiral coils K ( 29mm,30 turns, 8mil trace, 6mil space, 4 layers), spiral coil J ( 29mm, 35 turns, 6mil trace, 6mil space, 2 layers) and stretched rectangular coil A ( 100 x 15 mm, 23 turns, 6mil trace, 6mil space, 4.06mm loop stepping, 4 layers ) are attached to  perpendicular walls . The 4.5 mm copper BB pellet will be droped and I hope to obtain the values from respective coil sensors.

Can you recommend a capacitor valuethat I may purchase  (I'm doing a proff of concept ) , focusing on sensitivity?

I'm aware the capacitors are surface mounted, and plan to purchase them from Jamaco Electronics.

Thank you very much for your time and efforts.

Sincerely,

Alexander Luis

Dear Mr. Lapointe,
I'm very sorry for taking much of your time, but again as a non engineer and non programmer, you or the engineers at Texas Instrument are probably the only ones who can answer my questions.
I decided to buy an oscilloscope to see the out put to the SCL and SDA in my Arduino Uno , and I can see clearly the square wave forms.

I am also using a logic Level Shifter 4-Channel, Bidirectional in the following connections:

LDC1614EVM 3.3 v to Arduino 3.3v
LDC1614EVM GND to Arduino GND
LDC1614EVM INTB to Arduino GND
LDC1614EVM SD to Arduino GND
LDC1614EVM ADDR to Arduino GND (works better than at 3.3 v)
LDC1614EVM SDA to Arduino SDA ( 4.7K pull up resistors)
LDC1614EVM SCL to Arduino SCL (4.7K pull up resistors)

Inputs from Arduino go into the logic Level Shift, and output into LDC1614EVM.

I have been playing around with Kylie Chesner's two programs and the outputs are either zeros or 65535(depending which program I use).

Questions:
1. As I move my "target" (copper BB pellet) conductor to and away from the coil should the output values change?
2. Should Kylie's sketch work as the GUI provided by Ti ?
3. All I want for now is to obtain the alternating "RAW DATA" as the GUI provides.
4. Is there a working sketch which I may use on my Arduino Uno?

I really want to thank you for any information you can provide, and for all your efforts.

Sincerely,
Alexander Luis

Dear Alex,

Which version of Arduino are you using? As I googled, Arduino UNO and NANO both have a logical voltage of 5V. However, the LDC1614EVM board used the MSP430F5528 which has a logical voltage of 3.3V.

I have the same problem you have. I connected the sensor with Arduino NANO's I2C but I always get 0 data for each channel. Have you figured out a plausible solution?

Thank you! 

Best,

Yinsen

Dear Yinsen, Thank you for responding. You are RIGHT. 3.3 volts was the answer and my Arduino is WORKING !! Thank you very much.
Sincerely,

Alexander

Dear Alex,

Thank you so much for your reply! I feel happy and excited that your arduino is working. Could you let me know how you convert the 5V SCL SDA pins of arduino to 3.3V? Thank you for your kind help in advance!

Best,

Yinsen

Dear Yinsen,

I connected two 4.7 K Ohm resistors (pull-up) to the 3.3 v on the Arduino. The Arduino has a 5v and a 3.3 v source so don't use the 5 out source.

Alex

Dear Alex,

Thank you again for your kind reply. Have you ever used any 5V to 3.3V level shifter to connect the LDC 1614 sensor to the I2C of the arduino? Thank you for your kind reply in advance.

Have a wonderful weekend!

Best, Yinsen

Dear Yinsen,

Yes, I have used a shift level register BUT not with the LDC1614EVM...it did NOT work. SCL and SDA all run on 3.3 volts with 4.7K pull-up resistor.

Good luck.

Alexander

Dear Alex,

I have tried to add two 4.7K pull-up resistor on the SDA and SCK lines and connect the VCC of LDC 1614 to the 3.3V reference VCC on the Arduino NANO which has logic voltage 5V. However, I still get all zeros no matter how I try to use a metal to activate the sensors. 

Could you please show me how you connect the pins to make LDC 1614 working? Are you using any logic 5V to 3.3V shifter on the bus?

Thank you so much for your kind help and reply!

Best,

Yinsen