Beginners • i2cdetect shows no devices

Hi all,
I’m new to the Raspberry Pi world and currently setting up I2C sensors on a Raspberry Pi 5. I’ll do my best to explain the issue clearly.

Problem
I’m trying to connect multiple sensors (AS7341, BME680, and others) to a Raspberry Pi 5 or Raspberry Pi 5 via I2C.
However, when I run: sudo i2cdetect -y 1
I only get a grid of dashes (--), meaning no devices are detected on i2c-1.

Yet, when I check other I2C buses (i2c-11 and i2c-12), I see multiple active addresses, including 0x39, which is expected for the AS7341.

Trying to read from the sensor using: sudo i2cget -y 11 0x39 0x00
Results in: Error: Read failed

Wiring Setup
I’ve wired the AS7341 sensor to the Pi as follows (see photo attached):
VCCPin 1
GNDPin 6
SDAPin 3
SCL. Pin 5

I also added two 10kΩ pull-up resistors to SDA and SCL, but it didn’t change the results.
Only one sensor is connected at the moment.

Please note I'm very new to this so it's likely I'm doing something silly with the wiring/hardware !


Steps Taken
1) SSH into the Pi from my Mac (I don’t have a monitor or keyboard for direct access).
2) Enabled I2C via raspi-config and confirmed that /dev/i2c-1 exists.
3) Checked for connected I2C devices using:
sudo i2cdetect -y 1 # No response (empty)
sudo i2cdetect -y 11 # Shows multiple addresses, including 0x39
sudo i2cdetect -y 12 # Also detects multiple devices
4) Tried reading from the sensor, but it fails with "Read failed".

I2C Scan Results
i2c-1 does not detect any devices:
sudo i2cdetect -y 1
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --

i2c-11 and i2c-12 detect devices:
sudo i2cdetect -y 11
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: 08 09 0a 0b 0c 0d 0e 0f
10: 10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f
20: 20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f
30: -- -- -- -- -- -- -- -- 38 39 3a 3b 3c 3d 3e 3f
40: 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: 60 61 62 63 64 65 66 67 68 69 6a 6b 6c 6d 6e 6f
70: 70 71 72 73 74 75 76 77

sudo i2cdetect -y 12
(Similar result as above)

NB: I tried using two different Raspberry Pi (a 4 and a 5) and the issue is identical.
The board is powered via a wall socket, not through the Mac. The USB connection is only for control.

Any help highly appreciated !

Statistics: Posted by kansas 3948 — Fri Feb 14, 2025 7:04 pm — Replies 2 — Views 45

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