T-Echo Card get it now
Overview
T-Echo Card is a compact, low-power IoT development board built around the nRF52840 microcontroller. It combines long-range LoRa communication (SX1262), multi-constellation GNSS (L76K), 9-axis IMU (ICM20948), a 0.42" OLED display, audio recording/playback (MP34DT05 + MAX98357), and solar charging in a credit-card-sized form factor (90 × 60 × 9.5 mm). Supports BLE 5, Thread, Zigbee, ANT, NFC, and 802.15.4 out of the box.
Quick Start
Hardware Assembly
Arduino (via Adafruit nRF52 BSP)
- Install Arduino IDE
- Add the Adafruit nRF52 board URL:
https://adafruit.github.io/arduino-board-index/package_adafruit_index.json - Install Adafruit nRF52 board package
- Select Adafruit Feather nRF52840 Express (or closest nRF52840 variant)
- Install the required libraries listed in Software Libraries
- Clone T-Echo-Card and open an example sketch
- Click Upload
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Key Features
- nRF52840 @ 64 MHz, 256 kB RAM, 1 MB internal Flash + 32 Mbit external SPI Flash
- SX1262 LoRa transceiver, 400–945 MHz (variants: 433 / 868 / 915 / 920 MHz)
- L76K multi-constellation GNSS (GPS, GLONASS, BeiDou, QZSS)
- ICM20948 9-axis IMU (accelerometer + gyroscope + magnetometer)
- 0.42" OLED display (SSD1306/SSD1315, 72 × 40 px, I2C)
- MP34DT05 PDM digital MEMS microphone + MAX98357 I2S mono amplifier
- WS2812C-2020 RGB LED (256 brightness levels)
- Solar charging: 0.25 W, 5 V
- Wireless: BLE 5, Thread, Zigbee, ANT, NFC, 802.15.4, Bluetooth Mesh
- Compact: 90 × 60 × 9.5 mm
Specifications
| Parameter | Value |
|---|---|
| SOC | nRF52840 |
| CPU | ARM Cortex-M4F @ 64 MHz |
| RAM | 256 kB |
| Flash (internal) | 1 MB |
| Flash (external) | 32 Mbit SPI (ZD25WQ32CEIGR) |
| LoRa | SX1262, 400–945 MHz |
| GNSS | L76K (GPS / GLONASS / BeiDou / QZSS) |
| Display | 0.42" OLED, SSD1306/SSD1315, 72 × 40 px, I2C |
| IMU | ICM20948, 9-axis, I2C |
| Microphone | MP34DT05 MEMS, PDM |
| Speaker | MAX98357 I2S, 8 Ω 1 W |
| RGB LED | WS2812C-2020 |
| Solar | 0.25 W, 5 V |
| Wireless | BLE 5, Thread, Zigbee, ANT, NFC, 802.15.4 |
| Dimensions | 90 × 60 × 9.5 mm |
Pin Diagram
LoRa (SX1262)
| SX1262 | SCK | MOSI | MISO | CS | RST | BUSY | INT (DIO1) |
|---|---|---|---|---|---|---|---|
| nRF52840 | GPIO13 | GPIO15 | GPIO17 | GPIO11 | GPIO7 | GPIO14 | GPIO40 |
GNSS (L76K)
| L76K | TX | RX | 1PPS | Wake Up | EN | RF EN |
|---|---|---|---|---|---|---|
| nRF52840 | GPIO19 | GPIO21 | GPIO23 | GPIO25 | GPIO47 | GPIO29 |
Display (OLED SSD1315)
| SSD1315 | SDA | SCL |
|---|---|---|
| nRF52840 | GPIO36 | GPIO34 |
IMU (ICM20948)
| ICM20948 | SDA | SCL |
|---|---|---|
| nRF52840 | GPIO36 | GPIO34 |
Flash (ZD25WQ32CEIGR)
| ZD25WQ32C | CS | SCLK | MOSI | MISO |
|---|---|---|---|---|
| nRF52840 | GPIO12 | GPIO4 | GPIO6 | GPIO8 |
Audio
| Function | GPIO |
|---|---|
| Microphone CLK | GPIO35 |
| Microphone DATA | GPIO37 |
| Speaker EN | GPIO43 |
| Speaker BCLK | GPIO16 |
| Speaker DATA | GPIO20 |
| Speaker WS (LRCK) | GPIO22 |
RGB LED (WS2812)
| Function | GPIO |
|---|---|
| WS2812 #1 | GPIO39 |
| WS2812 #2 | GPIO44 |
| WS2812 #3 | GPIO28 |
Other
| Function | GPIO |
|---|---|
| Button (KEY_1) | GPIO42 |
| Battery ADC | GPIO2 |
| Battery Measurement Control | GPIO31 |
| RT9080 Enable | GPIO30 |
Dimensions
Schematic
Datasheet
- nRF52840 Datasheet
- SX1262 Datasheet
- ICM-20948 Datasheet
- L76K Datasheet
- MAX98357 Datasheet
- MP34DT05 Datasheet
Software Libraries
Required Libraries
FAQ
Q. Does T-Echo Card support NFC? A. The hardware supports NFC, but the default firmware does not currently enable it.
Q. Which LoRa frequency variant should I choose? A. Choose based on your region: 915 MHz (North America), 868 MHz (Europe), 920 MHz (Japan/Korea), 433 MHz (Asia/other).
Changelog
| Version | Date | Notes |
|---|---|---|
| V1.0 | — | Initial release |