Use with FT232H Breakout board

[adminnz]

I have a Adafruit NAU7802 connected via JST SH 4-pin cable into an Adafruit FT232H.
The FT232H has its i2c switched to ON.
The FT232H is connected to a windows 11 computer.

when i run the sample:

# SPDX-FileCopyrightText: 2023 Cedar Grove Maker Studios
# SPDX-License-Identifier: MIT

"""
nau7802_simpletest.py  2023-01-13 2.0.2  Cedar Grove Maker Studios

Instantiates two NAU7802 channels with default gain of 128 and sample
average count of 2.
"""

import time

import board

from cedargrove_nau7802 import NAU7802

# Instantiate 24-bit load sensor ADC; two channels, default gain of 128
nau7802 = NAU7802(board.I2C(), address=0x2A, active_channels=2)


def zero_channel():
    """Initiate internal calibration for current channel.Use when scale is started,
    a new channel is selected, or to adjust for measurement drift. Remove weight
    and tare from load cell before executing."""
    print(
        "channel {0:1d} calibrate.INTERNAL: {1:5s}".format(
            nau7802.channel, str(nau7802.calibrate("INTERNAL"))
        )
    )
    print(
        "channel {0:1d} calibrate.OFFSET:   {1:5s}".format(
            nau7802.channel, str(nau7802.calibrate("OFFSET"))
        )
    )
    print(f"...channel {nau7802.channel:1d} zeroed")


def read_raw_value(samples=2):
    """Read and average consecutive raw sample values. Return average raw value."""
    sample_sum = 0
    sample_count = samples
    while sample_count > 0:
        while not nau7802.available():
            pass
        sample_sum = sample_sum + nau7802.read()
        sample_count -= 1
    return int(sample_sum / samples)


# Instantiate and calibrate load cell inputs
print("*** Instantiate and calibrate load cells")
# Enable NAU7802 digital and analog power
enabled = nau7802.enable(True)
print("Digital and analog power enabled:", enabled)

print("REMOVE WEIGHTS FROM LOAD CELLS")
time.sleep(3)

nau7802.channel = 1
zero_channel()  # Calibrate and zero channel
nau7802.channel = 2
zero_channel()  # Calibrate and zero channel

print("READY")

### Main loop: Read load cells and display raw values
while True:
    print("=====")
    nau7802.channel = 1
    value = read_raw_value()
    print(f"channel {nau7802.channel:1.0f} raw value: {value:7.0f}")

    nau7802.channel = 2
    value = read_raw_value()
    print(f"channel {nau7802.channel:1.0f} raw value: {value:7.0f}")

I get what appear to be random values being printed out. For example

*** Instantiate and calibrate load cells
Digital and analog power enabled: True
REMOVE WEIGHTS FROM LOAD CELLS
channel 1 calibrate.INTERNAL: True 
channel 1 calibrate.OFFSET:   True 
...channel 1 zeroed
channel 2 calibrate.INTERNAL: True 
channel 2 calibrate.OFFSET:   True 
...channel 2 zeroed
READY
=====
channel 1 raw value:    -235
channel 2 raw value:      71
=====
channel 1 raw value:    -144
channel 2 raw value:     176
=====
channel 1 raw value:     -77
channel 2 raw value:     161
=====
channel 1 raw value:    7309
channel 2 raw value:     116
=====
channel 1 raw value:       2
channel 2 raw value:     135
=====
channel 1 raw value:     -67
channel 2 raw value:     172
=====
channel 1 raw value:     -21
channel 2 raw value:      29
=====
channel 1 raw value:      64
channel 2 raw value:     204
=====
channel 1 raw value:      27
channel 2 raw value:      74
=====

Just as a test, i disconnected the load cell wires from the NAU7802 and it still prints out random numbers.

[robo32]

If you try to convert te numbers to real values they make a lot more sense. Because it is a 24bit ADC the value can become really high so you are problably seeing noise or something.