{"slug": "esp32-into-a-speech-to-text-device", "title": "ESP32 Into a Speech-to-Text Device", "summary": "Project that turns an ESP32 microcontroller into a speech-to-text device using an INMP441 microphone and an OLED display. Because the ESP32 lacks the processing power for local speech recognition, the system records audio and sends it to the cloud-based Wit.ai API, which returns the transcribed text for display. The author notes that the setup is simple, requiring no extra hardware like a Raspberry Pi, and that the live text display on the OLED makes the project feel polished and futuristic.", "body_md": "Typing commands into a serial monitor feels old once you start playing with voice interfaces.\nSo I decided to try something more interesting — building a small ESP32 Speech to Text system using an INMP441 I2S microphone and an OLED display. The setup listens to speech, sends audio to a cloud API, and converts spoken words into text almost instantly.\nAnd honestly, seeing your own words appear live on a tiny OLED screen feels surprisingly futuristic for such a small project.\nAt first, I thought about running everything directly on the ESP32.\nThen reality hit.\nSpeech recognition models are heavy. The ESP32 simply doesn’t have enough processing power or memory to run large speech-to-text models locally in a reliable way. Instead of fighting hardware limitations for days, I used a cloud-based speech recognition service called Wit.ai.\nThe ESP32 only handles:\nThe cloud handles the difficult AI processing.\nWay simpler.\nThe workflow is actually pretty clean.\nThe INMP441 microphone captures audio using the I2S protocol. The ESP32 records the audio as 16-bit PCM data and sends it over HTTPS to Wit.ai using WiFi.\nOnce processed, Wit.ai sends back the recognized text in JSON format.\nThe ESP32 extracts the text and displays it on:\nSo the whole system behaves almost like a tiny voice assistant.\nPress button → speak → get text.\nThe hardware setup is very small:\nThat’s it.\nNo extra audio shield.\nNo Raspberry Pi.\nNo expensive AI hardware.\nI honestly expected cloud AI setup to be painful.\nBut the process was surprisingly simple:\nDone.\nThe ESP32 sends raw audio directly to:\napi.wit.ai\nusing HTTPS requests.\nNo custom server setup required.\nOne thing I really liked was the OLED status updates.\nThe display switches between:\nIt makes the device feel interactive instead of just dumping logs into Serial Monitor.\nOnce the recognized text appears on the OLED, the project suddenly feels much more polished.\nThis setup can easily evolve into:\nYou could even combine it with text-to-speech later and create a complete two-way voice assistant using only ESP32 hardware.\nFor a small microcontroller project, this one feels surprisingly close to real-world AI systems.", "url": "https://wpnews.pro/news/esp32-into-a-speech-to-text-device", "canonical_source": "https://dev.to/david_thomas/esp32-into-a-speech-to-text-device-c3m", "published_at": "2026-05-22 10:22:57+00:00", "updated_at": "2026-05-22 11:05:21.410110+00:00", "lang": "en", "topics": ["hardware", "artificial-intelligence", "cloud-computing", "products"], "entities": ["ESP32", "INMP441", "Wit.ai", "OLED"], "alternates": {"html": "https://wpnews.pro/news/esp32-into-a-speech-to-text-device", "markdown": "https://wpnews.pro/news/esp32-into-a-speech-to-text-device.md", "text": "https://wpnews.pro/news/esp32-into-a-speech-to-text-device.txt", "jsonld": "https://wpnews.pro/news/esp32-into-a-speech-to-text-device.jsonld"}}