DFRobot Gravity Offline Voice Recognition stops sending I2C Codes after a while
hape_53631 2026-02-16 22:58:01 139 Views2 Replies hi
i'm using the DFRobot Gravity Offline Speech Recognition module. Everything works fine. But after a while the module recognizes the command (the voice over the speaker ist telling the command but the I2C Bus doesn't send nothing. If i power off power on the system it works like before but stops after a while (like 7 minutes and 50 recognized commands). But it could be also shorter time and below 50 commands.
Does anyone know this strange error?
The module is on 5V so it seems not to be low volted.
Any ideas?
sincerly
hape
Communication issues between an Arduino and DFRobot Gravity modules—especially audio or voice recognition units—often trace back to insufficient peak current or a missing common ground. If your module is powered by an external source while the Arduino is on USB, ensure the GND pins are tied together; without this, the I2C or Serial logic levels have no stable reference, leading to "ghost" data or complete silence. For high-draw modules like the DFPlayer, the sudden current spike when the speaker activates can cause the local voltage to sag below the IC's $3.2V$ threshold, triggering a reset. Adding a $1000\mu F$ electrolytic capacitor across the module's VCC and GND pins usually stabilizes these transients. If you are using the DFPlayer Mini specifically, don't forget the $1k\Omega$ resistors on the RX/TX lines to suppress the switching noise from the MCU's serial lines, which otherwise manifests as a constant hum or "buzz" in the audio output.
reference:
https://www.pcbway.com/project/shareproject/Offline_Voice_Recognition_Hub_Based_on_ESPNOW_739c03c9.html
https://www.digikey.com/en/products/filter/aluminum-electrolytic-capacitors/58
Oliver.Taylor 
