Can't read data from 4-Channel 16-Bit ADC for Raspberry Pi (ADS1115)

yiy · August 3, 2020, 3:20pm

Hi there,
I can’t read data from this 4-chn ADC. Please check the screenshot below. It is Pi 4 ModelB 8G. Thank you very much!

Baozhu · August 4, 2020, 12:49am

According to the software instructions, after your Install script has executed, you will need to re-install the system.And then you get the data.

yiy · August 4, 2020, 12:20pm

That’s exactly what I did.
Install driver -> power off Pi -> install HAT -> power up Pi -> check installation status and read data.
What showed in the screenshot is the result from the last step.

Baozhu · August 5, 2020, 12:32am

https://jumpnowtek.com/rpi/Using-ads1115-ADCs-with-Raspberry-Pis.html
Can this article help you ? @yiy

yiy · August 6, 2020, 2:43pm

I added those parameters in the “config.txt” followed the instruction in your link. But it didn’t work. Still can’t read data from the hat.
Also I used the python code from the link “https://github.com/ControlEverythingCommunity/ADS1115/blob/master/Python/ADS1115_4Channels.py#L8” mentioned in another thread in your forum, it didn’t work either.

Did you test the hat on Pi 4 Rev B version? I am wondering whether it’s compatible with Pi4 Rev B or not. Thank you!

xian · September 7, 2020, 1:05pm

Hi, I have exactly the same problem as yiy - followed the steps from scratch on a fresh (and up-to-date) installation of a raspberry pi 4B [4 GB, Revision 1.1]:
in*_input in the path …/i2c-1/1-0048/ don’t exist …
however, from /sys/class/…/1-0048/iio:device0/in_voltage1_raw (and voltage2,… ) I get some reading, that is different every time i call it, and that changes systematically when I add some defined voltage

yiy · September 9, 2020, 1:30pm

Thanks. Can you provide the full path to the reading?

xian · September 9, 2020, 1:56pm

whithin this path: /sys/devices/platform/soc/*04000.i2c/i2c-1/1-0048/iio:device0/
you can find the different in_voltage#_raw to read out the different inputs; you just need to replace the * for whatever it is in your PI but it always ends with 04000.i2c

as an alternative, i could read out the first input vs ground with code from this link:

github.com

ControlEverythingCommunity/ADS1115/blob/master/Python/ADS1115_4Channels.py

# Distributed with a free-will license.
# Use it any way you want, profit or free, provided it fits in the licenses of its associated works.
# ADS1115
# This code is designed to work with the ADS1115_I2CADC I2C Mini Module available from ControlEverything.com.
# https://www.controleverything.com/content/Analog-Digital-Converters?sku=ADS1115_I2CADC#tabs-0-product_tabset-2

import smbus
import time

# Get I2C bus
bus = smbus.SMBus(1)

# ADS1115 address, 0x48(72)
# Select configuration register, 0x01(01)
#		0xC483(50307)	AINP = AIN0 and AINN = GND, +/- 2.048V
#				Continuous conversion mode, 128SPS
data = [0xC4,0x83]
bus.write_i2c_block_data(0x48, 0x01, data)

time.sleep(0.5)

This file has been truncated. show original

but before I had to remove the entry dtoverlay=ads1115 from the /boot/config.txt (or use the uninstall script).
now i do just need to figure out how to read out differentially two other inputs…

something seems to be broken with the device tree not properly building up… i guess this is a problem from the raspberry side?

Baozhu · September 10, 2020, 12:10am

https://wiki.seeedstudio.com/4-Channel_16-Bit_ADC_for_Raspberry_Pi-ADS1115/#platforms-supported @xian We update the wiki.

yiy · September 10, 2020, 12:35pm

Great. Thank you very much!