ESPHome not found i2c bmp085 (bmp185)

ESPHome
,
1

Hi folks.

I’ve configured esp8266 nodemcuv2 with the following code to have bmp185 barometric readings:

i2c:
  sda: GPIO4
  scl: GPIO5
  scan: true

sensor:
  - platform: bmp085
    temperature: 
      name: "prueba esc temp"
    pressure: 
      name: "prueba esc pres"
    update_interval: 60s

And i’m getting the following log:

[02:27:57][C][i2c.arduino:071]: I2C Bus:
[02:27:57][C][i2c.arduino:072]:   SDA Pin: GPIO4
[02:27:57][C][i2c.arduino:073]:   SCL Pin: GPIO5
[02:27:57][C][i2c.arduino:074]:   Frequency: 50000 Hz
[02:27:57][C][i2c.arduino:086]:   Recovery: bus successfully recovered
[02:27:57][I][i2c.arduino:096]: Results from i2c bus scan:
[02:27:57][I][i2c.arduino:098]: Found no i2c devices!
[02:27:57][C][bmp085.sensor:044]: BMP085:
[02:27:57][C][bmp085.sensor:045]:   Address: 0x77
[02:27:57][E][bmp085.sensor:047]: Connection with BMP085 failed!
[02:27:57][C][bmp085.sensor:049]:   Update Interval: 60.0s
[02:27:57][C][bmp085.sensor:051]:   Temperature 'prueba esc temp'
[02:27:57][C][bmp085.sensor:051]:     Device Class: 'temperature'
[02:27:57][C][bmp085.sensor:051]:     State Class: 'measurement'
[02:27:57][C][bmp085.sensor:051]:     Unit of Measurement: '°C'
[02:27:57][C][bmp085.sensor:051]:     Accuracy Decimals: 1
[02:27:57][C][bmp085.sensor:052]:   Pressure 'prueba esc pres'
[02:27:57][C][bmp085.sensor:052]:     Device Class: 'pressure'
[02:27:57][C][bmp085.sensor:052]:     State Class: 'measurement'
[02:27:57][C][bmp085.sensor:052]:     Unit of Measurement: 'hPa'
[02:27:57][C][bmp085.sensor:052]:     Accuracy Decimals: 1
[02:27:57][E][component:082]:   Component bmp085.sensor is marked FAILED

I’ve tried with external power source but same happen.

wiring:

WhatsApp Image 2024-06-04 at 02.36.26
WhatsApp Image 2024-06-04 at 02.36.261600×634 338 KB

Any ideas?

PS sorry for the post format, don´t known how will be shown. My first one.

2

very much a guess. But have you powered the BMP from the esp8266 rather than an external supply. I think you need the gnd on both devices to be connected, but I am no expert. Yaml looks fine to me.

3

As Arh said: there’s no GND connected from sensor to esp board on above picture - it’s mandatory. Also check if sensor has onboard pull-up resistors,if not add 4k7-10k resistor from scl to +V and from sda to +V.

4

Your post is correctly formatted . Thanks for the effort.

5

Check all the breadboard connections as they often have bad contacts. As Protoncek said there needs to be a ground to the module

6

Hello. Thanks for yours replies.
I’m again here trying to solve this issue.

I’m powering the sensor with the esp board, so gnd is conected.
Tried with and without 10k transistors as @Protoncek suggested. Still not working.

With a multimeter tested continuity on conections and are ok.
tested voltages on sensor side. With and w/o resistors the same:
vin-gnd: 4.5V
sda-gnd: 4.4V
scl-gnd: 4.4V

Just to start from the most basic:
sda on esp to sda on sensor and scl to scl?

Just in case, I also have a DHT22 sensor working on D5 without issue.

Thanks in advance!

7

My guess now is the sensor is faulty. It does happen sometimes.

8

It’s not 5V sensor, and your module doesn’t have regulator, you fried it.

9

Actually, it does: on above picture bottom left pin is 3.3V output. Since all esp’s run on 3.3V all these boards do have regulator on-board, and it’s enough for these small sensors to have them powered from it.
But if sensor was indeed connected to 5V (which is was, as it seems) than i agree it might be “deceased”.

10

Sensor module doesn’t have regulator (or it’s skipped).
Bmp085 is max 3.6V sensor and his measured 4.4V data line voltage confirms that.
Obviously Esp devboard has regulator…
And hopefully still undamaged I2C pins…
.

11

aha… you mean BMP module… agreed, that one doesn’t have one.

12

Indeed it was never powered with 5V… the power source i tried with has 3.3V and 5V option and was set to 3.3.

Anyway… i’m now ordering a new sensor and have a spare board.

Thanks you all.

13

I think you are wrong now. You measured 4.4-4.5V on your lines, that’s not possible if powered 3.3V.

14

Hi all!

New sensor arrived and it’s working.
By the way I noticed my tester who was reading 4.5V was faulty also.

Thanks you all!