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)

1. Install Arduino IDE
2. Add the Adafruit nRF52 board URL: https://adafruit.github.io/arduino-board-index/package_adafruit_index.json
3. Install Adafruit nRF52 board package
4. Select Adafruit Feather nRF52840 Express (or closest nRF52840 variant)
5. Install the required libraries listed in Software Libraries
6. Clone T-Echo-Card and open an example sketch
7. 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

• T-Echo Card Schematic

Datasheet

• nRF52840 Datasheet
• SX1262 Datasheet
• ICM-20948 Datasheet
• L76K Datasheet
• MAX98357 Datasheet
• MP34DT05 Datasheet

Software Libraries

• T-Echo-Card GitHub Repository

Required Libraries

• Adafruit_BusIO
• Adafruit-GFX-Library
• Adafruit_SPIFlash
• Adafruit_NeoPixel
• ICM20948_WE
• cpp_bus_driver

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