Specifications
| Type | Mono Class-D amplifier with a built-in DAC and an I2S input. The ESP32 sends numbers; the chip drives the speaker |
|---|---|
| Chip | NS4168 (Nsiway), ESOP-8. Always an I2S listener: the ESP32 makes every clock |
| Supply | 3.3 V on 3V3, as printed. Not 5 V: at 5 V the chip's logic HIGH is 3.5 V, above what a 3.3 V GPIO gives |
| Host | A 3.3 V board with an I2S peripheral, such as the ESP32-S3. An Arduino Uno or Nano has no I2S |
| Header | 6-pin right-angle male, 2.54 mm: GND, 3V3, LRCLK, BCLK, DIN, CTRL. 22 Ω in each I2S line; CTRL through 22 kΩ |
| CTRL | HIGH to play, LOW to shut down (about 1 µA). Unconnected is off or undefined, so always drive it |
| Channel | Mono: plays the right channel with the L/R jumper open, as shipped, and the left with it bridged (CTRL then sits at 1.03 V) |
| Output | Bridge-tied, neither wire is ground. 1.2 W into 4 Ω at 3.6 V (datasheet, 10 % THD+N); about 1 W at 3.3 V, worked out |
| Speaker | A bare 4 or 8 Ω speaker on a 1.25 mm 2-pin socket. Never headphones, GND or another amplifier's input |
| Protection | Anti-clipping (turns its gain down up to 10 dB), overcurrent, over-temperature and under-voltage |
| Sample rate | 8 to 96 kHz; bit clock 16, 24, 32, 48 or 64 per frame. The book's sketches use 16 kHz, 16-bit stereo |
| Board | 22.4 × 30.4 mm TinkerBlock board, two LEGO-compatible holes 16 mm apart, red power LED |
| In the box | The I2S audio kit: TK100, TK101 microphone, TK103 DAC, a 4 Ω 3 W speaker that plugs into the TK100, a 3.5 mm cable and a 3.5 mm to RCA cable. Headers fitted |
What it does
The TK100 plays sound on a speaker from numbers. The ESP32-S3 sends samples on three I2S wires, LRCLK, BCLK and DIN, and the NS4168 on the board turns them into a voltage and amplifies it to drive the speaker: DAC and amplifier in one chip. The ESP32 does only the arithmetic.
Two things to know before wiring
- CTRL must be driven HIGH. LOW or unconnected, the chip is off, and the power LED stays lit either way. Every sketch here sets CTRL HIGH before it plays.
- Neither speaker wire is ground. Both AUDIO + and AUDIO - switch. Only a speaker goes across them: never GND, never headphones, never another amplifier's input. And the board is 3.3 V only.
Wiring, in four lines
- GND to GND, 3V3 to 3V3.
- BCLK to GPIO 15, LRCLK to GPIO 16, DIN to GPIO 17.
- CTRL to GPIO 18, driven HIGH in the sketch.
- The kit's 4 Ω speaker into the white socket.
Where to start
The handbook below is nine short articles. Read What is on the board before wiring and CTRL: on, off, left or right before your first sketch. First sound plays a scale; Record and play back adds the microphone.
The rest of the kit
The TK100 comes in the I2S audio kit with two other blocks, each with its own handbook on the same pin map: the TK101 PDM microphone, which records, and the TK103 I2S DAC, which feeds headphones or powered speakers.
When it doesn’t work
- Why is there no sound when the LED is on?
- The LED only shows power. The chip stays off until CTRL is driven HIGH. Wire CTRL to a GPIO (18 in this book) and set it HIGH before playing.
- Does it work with an Arduino Uno?
- No. The Uno's ATmega328P has no I2S peripheral and runs 5 V logic. Use an ESP32-S3, which has two I2S ports and can put them on almost any pin.
- Can I plug headphones into it?
- No. The output is a switching, speaker-level signal on two wires, neither of them ground. For headphones or powered speakers, use the TK103 DAC from the same kit.
- Why does a stereo song play only one side?
- The NS4168 is mono and plays one channel: the right as shipped, the left with the L/R jumper bridged. Two TK100s on the same three wires, one bridged, make stereo.
- Can I run it from 5 V to make it louder?
- Not with an ESP32 driving it. At 5 V the chip needs 3.5 V to see a logic HIGH, more than an ESP32 pin gives. Power it from 3V3; it gives about 1 W into the kit's 4 Ω speaker.
- My sketch will not compile: expected unqualified-id.
- The sketch names a pin PIN_CTRL, which the ESP32-S3 core already defines. Rename it; this book uses PIN_AMP_ON.