meshtastic
[Bug]: SHT45 not data
Category
Hardware Compatibility, Other
Hardware
Heltec V3
Is this bug report about any UI component firmware like InkHUD or Meshtatic UI (MUI)?
- [ ] Meshtastic UI aka MUI colorTFT
- [ ] InkHUD ePaper
- [ ] OLED slide UI on any display
Firmware Version
2.6.4.b89355f
Description
Environment Device: Meshtastic Heltec v3 (ESP32-based)
Sensor: Adafruit Sensirion SHT45 (I²C)
Wiring:
SCL → Pin 42 SDA → Pin 41 VCC → 3.3V GND → GND
Symptoms:
Sensor readings return nan% (humidity) and nan℃ (temperature)
No valid data received
Expected Behavior The SHT45 should report valid temperature and humidity readings when queried over I²C.
Actual Behavior The sensor fails to provide valid data, returning NaN (Not a Number) values instead.
Troubleshooting Steps Taken Checked wiring connections (ensured no loose connections, correct pin assignments).
Verified power supply (3.3V is stable, GND is properly connected).
Tested with a different microcontroller ESP-32 C6 to confirm the sensor works.
Relevant log output
ESP-ROM:esp32s3-20210327
Build:Mar 27 2021
rst:0x1 (POWERON),boot:0x28 (SPI_FAST_FLASH_BOOT)
SPIWP:0xee
mode:DIO, clock div:1
load:0x3fce3808,len:0x4bc
load:0x403c9700,len:0xbd8
load:0x403cc700,len:0x2a0c
entry 0x403c98d0
��@INFO | ??:??:?? 0
//\ E S H T /\ S T / C
INFO | ??:??:?? 0 Booted, wake cause 0 (boot count 1), reset_reason=reset
DEBUG | ??:??:?? 0 Filesystem files (909312/1572864 Bytes):
DEBUG | ??:??:?? 0 /prefs/channels.proto (57 Bytes)
DEBUG | ??:??:?? 0 /prefs/config.proto (201 Bytes)
DEBUG | ??:??:?? 0 /prefs/device.proto (114 Bytes)
DEBUG | ??:??:?? 0 /prefs/module.proto (100 Bytes)
DEBUG | ??:??:?? 0 /prefs/nodes.proto (557 Bytes)
DEBUG | ??:??:?? 0 /static/.gitkeep (0 Bytes)
DEBUG | ??:??:?? 0 /static/Logo_Black.svg.gz (602 Bytes)
DEBUG | ??:??:?? 0 /static/Logo_White.svg.gz (610 Bytes)
DEBUG | ??:??:?? 0 /static/apple-touch-icon.png.gz (3164 Bytes)
DEBUG | ??:??:?? 0 /static/favicon.ico.gz (2270 Bytes)
DEBUG | ??:??:?? 0 /static/icon.svg.gz (852 Bytes)
DEBUG | ??:??:?? 0 /static/index-b9vwykds.js.gz (222120 Bytes)
DEBUG | ??:??:?? 0 /static/index-wV0rbIjU.css.gz (16573 Bytes)
DEBUG | ??:??:?? 0 /static/index.html.gz (547 Bytes)
DEBUG | ??:??:?? 0 /static/mapbox-gl-DY02hNYD.js.gz (391221 Bytes)
DEBUG | ??:??:?? 0 /static/maplibre-gl-H6mDd47p.js.gz (210429 Bytes)
DEBUG | ??:??:?? 0 /static/robots.txt.gz (42 Bytes)
DEBUG | ??:??:?? 0 /static/site.webmanifest.gz (197 Bytes)
[ 779][I][esp32-hal-i2c.c:75] i2cInit(): Initialising I2C Master: sda=41 scl=42 freq=100000
[ 793][I][esp32-hal-i2c.c:75] i2cInit(): Initialising I2C Master: sda=17 scl=18 freq=100000
DEBUG | ??:??:?? 0 Power::lipoInit lipo sensor is not ready yet
DEBUG | ??:??:?? 0 Use analog input 1 for battery level
INFO | ??:??:?? 0 ADC config based on Two Point values and fitting curve coefficients stored in eFuse
INFO | ??:??:?? 0 Scan for i2c devices
[ 827][W][Wire.cpp:301] begin(): Bus already started in Master Mode.
DEBUG | ??:??:?? 0 Scan for I2C devices on port 2
[ 887][E][Wire.cpp:513] requestFrom(): i2cRead returned Error -1
INFO | ??:??:?? 0 SHT31 found at address 0x44
[ 901][W][Wire.cpp:301] begin(): Bus already started in Master Mode.
DEBUG | ??:??:?? 0 Scan for I2C devices on port 1
DEBUG | ??:??:?? 0 0x2 subtype probed in 2 tries
INFO | ??:??:?? 0 2 I2C devices found
DEBUG | ??:??:?? 0 acc_info = 0
INFO | ??:??:?? 0 S:B:43,2.6.4.b89355f
INFO | ??:??:?? 0 Build timestamp: 1743283504
DEBUG | ??:??:?? 0 Total heap: 294672
DEBUG | ??:??:?? 0 Free heap: 257196
DEBUG | ??:??:?? 0 Total PSRAM: 0
DEBUG | ??:??:?? 0 Free PSRAM: 0
DEBUG | ??:??:?? 0 NVS: UsedEntries 172, FreeEntries 458, AllEntries 630, NameSpaces 9
DEBUG | ??:??:?? 0 Setup Preferences in Flash Storage
DEBUG | ??:??:?? 0 Number of Device Reboots: 5
INFO | ??:??:?? 0 BLE OTA firmware version 0.3.0.87f0f2f
INFO | ??:??:?? 0 No WiFi OTA firmware available
INFO | ??:??:?? 0 Init NodeDB
[ 997][E][vfs_api.cpp:105] open(): /littlefs/static/static does not exist, no permits for creation
[ 1015][E][vfs_api.cpp:105] open(): /littlefs/prefs/db.proto does not exist, no permits for creation
INFO | ??:??:?? 1 Load /prefs/nodes.proto
INFO | ??:??:?? 1 Loaded /prefs/nodes.proto successfully
INFO | ??:??:?? 1 Loaded saved nodedatabase version 24, with nodes count: 2
INFO | ??:??:?? 1 Load /prefs/device.proto
INFO | ??:??:?? 1 Loaded /prefs/device.proto successfully
INFO | ??:??:?? 1 Loaded saved devicestate version 24
INFO | ??:??:?? 1 Load /prefs/config.proto
INFO | ??:??:?? 1 Loaded /prefs/config.proto successfully
INFO | ??:??:?? 1 Loaded saved config version 24
INFO | ??:??:?? 1 Load /prefs/module.proto
INFO | ??:??:?? 1 Loaded /prefs/module.proto successfully
INFO | ??:??:?? 1 Loaded saved moduleConfig version 24
INFO | ??:??:?? 1 Load /prefs/channels.proto
INFO | ??:??:?? 1 Loaded /prefs/channels.proto successfully
INFO | ??:??:?? 1 Loaded saved channelFile version 24
[ 1204][E][vfs_api.cpp:105] open(): /littlefs/prefs/uiconfig.proto does not exist, no permits for creation
ERROR | ??:??:?? 1 Could not open / read /prefs/uiconfig.proto
DEBUG | ??:??:?? 1 cleanupMeshDB purged 0 entries
DEBUG | ??:??:?? 1 Use nodenum 0xb03b92b4
DEBUG | ??:??:?? 1 Number of Device Reboots: 5
DEBUG | ??:??:?? 1 Expand short PSK #1
INFO | ??:??:?? 1 Wanted region 3, using EU_868
DEBUG | ??:??:?? 1 Coerce telemetry to min of 30 minutes on defaults
DEBUG | ??:??:?? 1 Save to disk 4
DEBUG | ??:??:?? 1 Opening /prefs/device.proto, fullAtomic=1
INFO | ??:??:?? 1 Save /prefs/device.proto
DEBUG | ??:??:?? 1 Use GPIO00 for button
DEBUG | ??:??:?? 1 SPI.begin(SCK=9, MISO=11, MOSI=10, NSS=8)
DEBUG | ??:??:?? 1 Use compiled/slipstreamed tzplaceholder
DEBUG | ??:??:?? 1 Set Timezone to GMT0
DEBUG | ??:??:?? 1 Read RTC time as 1
DEBUG | ??:??:?? 1 Start multicast thread
DEBUG | ??:??:?? 1 NeighborInfoModule is disabled
DEBUG | ??:??:?? 1 Rescan for I2C keyboard
DEBUG | ??:??:?? 1 Scan for I2C devices on port 2
DEBUG | ??:??:?? 1 Scan address 0x1f
DEBUG | ??:??:?? 1 Scan address 0x55
DEBUG | ??:??:?? 1 Scan address 0x5a
DEBUG | ??:??:?? 1 Scan address 0x5f
DEBUG | ??:??:?? 1 Scan for I2C devices on port 1
DEBUG | ??:??:?? 1 Scan address 0x1f
DEBUG | ??:??:?? 1 Scan address 0x55
DEBUG | ??:??:?? 1 Scan address 0x5a
DEBUG | ??:??:?? 1 Scan address 0x5f
INFO | ??:??:?? 1 External Notification Module Disabled
INFO | ??:??:?? 1 Turn on screen
DEBUG | ??:??:?? 1 haveGlyphs=1
DEBUG | ??:??:?? 1 waypoint wants a UI Frame
DEBUG | ??:??:?? 1 canned wants a UI Frame
DEBUG | ??:??:?? 1 SX126xInterface(cs=8, irq=14, rst=12, busy=13)
DEBUG | ??:??:?? 1 SX126X_DIO3_TCXO_VOLTAGE defined, using DIO3 as TCXO reference voltage at 1.800000 V
INFO | ??:??:?? 1 Start meshradio init
INFO | ??:??:?? 1 Radio freq=869.525, config.lora.frequency_offset=0.000
INFO | ??:??:?? 1 Set radio: region=EU_868, name=LongFast, config=0, ch=0, power=27
INFO | ??:??:?? 1 myRegion->freqStart -> myRegion->freqEnd: 869.400024 -> 869.650024 (0.250000 MHz)
INFO | ??:??:?? 1 numChannels: 1 x 250.000kHz
INFO | ??:??:?? 1 channel_num: 1
INFO | ??:??:?? 1 frequency: 869.525024
INFO | ??:??:?? 1 Slot time: 28 msec
INFO | ??:??:?? 1 Set radio: final power level=22
INFO | ??:??:?? 1 SX126x init result 0
INFO | ??:??:?? 1 Frequency set to 869.525024
INFO | ??:??:?? 1 Bandwidth set to 250.000000
INFO | ??:??:?? 1 Power output set to 22
Just test the esp32-c6 again and it's working fine.
[ 40100][V][esp32-hal-i2c-ng.c:262] i2cWrite(): i2c_master_transmit: bus=0 addr=0x44 handle=0x40821c64 size=1 [ 40119][V][esp32-hal-i2c-ng.c:308] i2cRead(): i2c_master_receive: bus=0 addr=0x44 handle=0x40821c64 size=6 📤 Publishing: {"temperature":26.15,"humidity":34.61,"rssi":-34,"ip":"192.168.1.150"} ✅ Publish SUCCESS
Having the same issue with the SHT40 Have you found a solution?
EDIT: seems like my issue is that the SHT40 is being recognized as a SHT31
EDIT2: Found the issue! 0xc8d is not recognized as an 4x in the i2c2wire scan port logic
Have the same Issue with a SHT40 as well as SHT41 - it only shows "NaN" (Firmware 2.7.3)
Having the same issue with the SHT40 Have you found a solution?
EDIT: seems like my issue is that the SHT40 is being recognized as a SHT31
EDIT2: Found the issue! 0xc8d is not recognized as an 4x in the i2c2wire scan port logic
Is there a solution to fix it by myself? Or only wait for a fix in the Meshtastic-Firmware?
Having the same issue with a SHT40 being incorrectly identified as a SHT31
INFO | ??:??:?? 2 DFRobot Rain Gauge found at address 0x1d INFO | ??:??:?? 2 SHT31 found at address 0x44 INFO | ??:??:?? 2 2 I2C devices found
Firmware 2.7.5 on a rp2040-lora
It's because the serial numbers arent specified in the firmware and it falls back to sht31 by default
Yeah I worked that part out, I found the part of the code and changed it to default to sht40, and seems to work well now.
