https://qihao.dev/en/Qihao's maker journal about learning 3D printing, electronics, and product building from scratch.enMon, 14 Sep 2026 00:00:00 GMThttps://qihao.dev/en/blog/tts-audio-assets-playback-jobs-cache/https://qihao.dev/en/blog/tts-audio-assets-playback-jobs-cache/The local voice platform originally called TTS again whenever the same text was sent, creating a duplicate MP3. Starting with that real duplicate-file problem, this article explains why audio assets and playback jobs should be separate, and how cache keys, history playback, resending, and legacy database migration fit together.QihaoMon, 14 Sep 2026 00:00:00 GMTConcept primerTTSAudio cachingData modelingESP32Voice platformSHA-256https://qihao.dev/en/works/001-esp32-s3-ai-voice-conversation-prototype/https://qihao.dev/en/works/001-esp32-s3-ai-voice-conversation-prototype/Building a button-triggered AI voice conversation prototype that records the user's voice, sends it to a server for language-model processing, and plays the spoken response through the device's speaker.QihaoThu, 20 Aug 2026 00:00:00 GMTAI HardwareESP32-S3AI Voice ConversationVoice InteractionHardware Prototypehttps://qihao.dev/en/blog/esp32-web-text-to-speech-local-voice-platform/https://qihao.dev/en/blog/esp32-web-text-to-speech-local-voice-platform/I moved the ESP32-S3 from playing audio embedded in firmware to speaking text entered dynamically in a browser. This article documents the working path from the web UI through local TTS and a task queue to the ESP32, MAX98357A, and speaker—and clearly marks the voice-input work that remains.QihaoSun, 13 Sep 2026 00:00:00 GMTProject progressESP32-S3MAX98357AText-to-speechFastAPII²SVoice bothttps://qihao.dev/en/blog/esp32-s3-max98357a-speaker-wiring-voice-playback/https://qihao.dev/en/blog/esp32-s3-max98357a-speaker-wiring-voice-playback/A hands-on ESP32-S3 voice playback build: adapt a two-pin speaker connector to the MAX98357A screw terminal, complete the five-wire I²S connection, and verify the audio output with three test tones and five web-generated voice clips.QihaoWed, 09 Sep 2026 00:00:00 GMTProblem solvedESP32-S3MAX98357AI²SSpeakerAudio playbackhttps://qihao.dev/en/blog/first-complete-circuit-board-electronic-dice/https://qihao.dev/en/blog/first-complete-circuit-board-electronic-dice/To practice soldering while ending up with something usable, I chose a YCA2109 electronic dice practice board. This article records how I started with a bare board and a bag of components, spent about five or six hours assembling, soldering, and troubleshooting it, and finally got the LEDs to light briefly.QihaoWed, 02 Sep 2026 00:00:00 GMTGrowth StorySoldering BasicsElectronic DiceCircuit BoardHardware PracticeBeginnerhttps://qihao.dev/en/blog/yca2109-electronic-dice-no-light-hot-ic-reversed/https://qihao.dev/en/blog/yca2109-electronic-dice-no-light-hot-ic-reversed/A freshly soldered YCA2109 electronic dice had all LEDs unlit when powered; the voltage after connecting the battery holder to the circuit board was only about 2.2V, and the two chips became noticeably hot after about 10 minutes. This article documents how I worked through the power supply, button, multimeter range, and input diode step by step, eventually finding that the two DIP chips were in the wrong orientation; after flipping them, the electronic dice resumed operation and could randomly stop on different numbers.QihaoWed, 02 Sep 2026 00:00:00 GMTProblem solvedYCA2109Electronic diceDIP chipHardware troubleshootingMultimeterhttps://qihao.dev/en/blog/esp32-st7789-seven-wire-pin-functions/https://qihao.dev/en/blog/esp32-st7789-seven-wire-pin-functions/When I first connected the GMT130-V1.0, I could only follow the wiring table. This article groups VCC, GND, BLK, RES, SCK, SDA, and DC into four categories, and walks along the complete display chain to explain how they turn ESP32 code into a visible image, and how to safely re-plan the wiring once you understand it.QihaoFri, 28 Aug 2026 00:00:00 GMTConcept primerESP32-S3ST7789GMT130-V1.0SPIHardware basicshttps://qihao.dev/en/blog/st7789-gmt130-spi-mode3-black-screen-fix/https://qihao.dev/en/blog/st7789-gmt130-spi-mode3-black-screen-fix/A GMT130-V1.0 had a working backlight but never displayed a single pixel, even though the driver chip and resolution were correct. This article retraces how I moved from a black screen on software SPI Mode 0 to hardware SPI that actually applies SPI_MODE3, then verified the fix with a five-color loop and a power-cycle test.QihaoMon, 24 Aug 2026 00:00:00 GMTProblem solvedESP32-S3ST7789GMT130-V1.0SPIHardware Debugginghttps://qihao.dev/en/blog/st7735-colored-edge-lines-blacktab-greentab/https://qihao.dev/en/blog/st7735-colored-edge-lines-blacktab-greentab/A 1.8-inch 128×160 ST7735 can already display the main content, but fixed colored lines remain on the right and bottom. This article uses a single-variable hands-on test to show how to identify initialization parameter mismatch from image offset, and verifies whether INITR_GREENTAB fits the current panel.QihaoWed, 19 Aug 2026 00:00:00 GMTProblem solvedESP32-S3ST7735ArduinoTFT displayHardware troubleshootinghttps://qihao.dev/en/blog/ai-shopping-list-hardware-parts/https://qihao.dev/en/blog/ai-shopping-list-hardware-parts/I thought that once I bought all the components for the ESP32-S3, I could just wire them up and debug; it was only when the microphone lacked soldered pins and the speaker terminal couldn't match that I understood AI can speed up problem-solving but cannot replace the foundation and judgment formed through practice.QihaoMon, 17 Aug 2026 00:00:00 GMTGrowth StoryAI LearningESP32-S3Hardware BasicsPractice Noteshttps://qihao.dev/en/blog/first-soldering-inmp441-failure/https://qihao.dev/en/blog/first-soldering-inmp441-failure/For my first time soldering pins onto an INMP441, I skipped the practice board and went straight to the real thing. Twenty minutes later, I had six oddly shaped solder joints. This failure taught me: tutorials and AI can teach knowledge, but hands-on skill only grows from practice.QihaoThu, 20 Aug 2026 00:00:00 GMTGrowth StoryESP32-S3INMP441First SolderingHardware LearningAI-Assisted Learning