ads1115 interfacing

Projects General Guidance
1

hi there, i got problems about connecting ti ads1115 to arduino uno.
scl is on analog 5, sda is on analog 4 vdd is on +5v, adr is on gnd.
i dont know where is the problem
(used http://www.i2cdevlib.com/ ads1115 library)_
Initializing I2C devices...
Testing device connections...
ADS1115 connection failed

Analog input #1 counts = 0 Voltage = 0.000000 Hit any key to continue

2

Are there pull-up resistors (about 4.7k each) on SDA and SCL?

3

Well the OP seems to have gone away but meanwhile - John, any particular reason to recommend 4k7? I ask because the TI data sheet, figure 23 sample schematic shows 10k. But then, it also shows a 3.3V Vcc.

4

My understanding is that a range of 1K to 10K should work and 4.7K is near the middle of the range.

Nick Gammon also recommends 4.7K: http://gammon.com.au/i2c

5

I have the breakout board for the ADS115 and a using the sketch from RetroLefty. edit with one change, uncomented this line

const int comparatorMode = 0x0003;    //disable comparitor

I have the wiper of a 10k linear pot connected to Analog Input 0 and the centrepoint of a 10k-10k voltage divider between Vcc and GND connected to Analog Input 1, using the device in differential mode. edit: the pot is wired correctly, I have used it on the Arduino built-in ADC with the expected results. The breakout board s getting power, the red LED is lit.

I'm getting a constant output value regardless of the pot setting:

Analog input #0 raw = 72 Millvolts = 13 Hit any key to continue

This is my circuit (10k pullups on SDA and SCL, ADR pulled to ground, 0.1uF decoupling cap):

ADS1115-test.png
ADS1115-test.png529×653 76 KB

6

This is the breakout poard pinout:

$(KGrHqN,!n8E63WLoHU1BO5oLj3Hhw~~60_12.JPG

7

Switching things around to read from AIn2 with AIn3 grounded, like this

const int channelSelect = 0x60E0; byte channel = 2;  //input wired to + AIN2 - gnd, single ended, 0 to +max range

gives the same constant reading of 72.

Changing the pull-ups on SDA and SCL from 10k to 3k3 (I don't have any 4k7 to hand) did not change this, either.

8

Sorry i forgot to write here, the problem was about my arduino uno board. I changed the board, everything went well.