MQ131 BREAKOUT+EASYC not reading data over I2C

TECHNICAL SUPPORT Sensors & Modules
1

Customer:

I’ve tested the MQ131 BREAKOUT board and found a problem. With the MQ131 BREAKOUT module the system works and Arduino reads the data correctly. However, when I switch to the MQ131 BREAKOUT+EASYC, Arduino cannot read the data. The developer team suspects a communication problem. I’m planning to send a replacement module to the developers to verify whether there’s a hardware issue.

Do you have any systems or differential I2C amplifier solutions for extending I2C lines?

Original message (Italian)

Dear [name removed], I finish to testing the board MQ1131 BREAKOUT but I found a problem. See the PDF attached. [name removed] Stefani Technical Department [email removed] Expansion Electronic Srl Via Delle Industrie, 18 [address removed] (VI) - ITALY
Tel.: – 827058 Web: www.expansion-electronic.eu Da: [name removed] - Expansione Electronic
Inviato: giovedì 22 gennaio 2026 16:59
A: ‘Soldered Electronics’
Oggetto: R: Update on Your Soldered Electronics Support Inquiry (#191917) Hello [name removed], In the pictures my application. With the module MQ131 BREAKOUT the system work, the Arduino read the data, but if change the module and use the MQ131 BREAKOUT+EASYC don’t read the data. The developer web team suppose have a communication problem. Tomorrow, I send at developer a new module to verify if have a hardware problem. I have buy your components at DIGI KEY, is possible buy direct ? Have any system of differential I2C amplifier line? [name removed] Stefani Technical Department [email removed] Expansion Electronic Srl Via Delle Industrie, 18 [address removed] (VI) - ITALY
Tel.: – 827058 Web: www.expansion-electronic.eu Da: [name removed] (Soldered Electronics)
Inviato: giovedì 22 gennaio 2026 14:56
A: [name removed]
Oggetto: Update on Your Soldered Electronics Support Inquiry (#191917)

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Attachment omitted in migration: 20260212-01 Technical Report MQ131 Breakout-EN SOLDERED.pdf

Originally submitted via the contact form on soldered.com on 12 February 2026. Migrated to the forum for community visibility.

2

Soldered Support:

The MQ131 is the high-concentration version that measures O3 levels from 10-1000 ppm. The version of this breakout with Qwiic/easyC (they’re equivalent) should work correctly using our library and requires no differential pair to connect the I2C line if it’s at a reasonable distance from the microcontroller (50cm).

We’re uncertain why you’re experiencing an error with your I2C readings. You can source the module directly from us and we’ll test it additionally before shipping it out to you.