Raspberry Pi Pico with Waveshare LoRa HAT

The Raspberry Pi Pico paired with a Waveshare LoRa module is a low-cost platform for LoRa radio projects. The original Pico and Pico W provide the RP2040 microcontroller, while Pico 2 and Pico 2 W use the newer RP2350; the Waveshare HAT or breakout adds the Semtech SX126x radio. Together they make a capable LoRa node that can run on battery for extended periods. This covers the hardware, wiring, and getting MicroPython talking to the radio.

The Hardware

Component	Notes
Raspberry Pi Pico	Original RP2040 board; 264KB SRAM and typically 2MB flash; no WiFi or Bluetooth. A good simple USB-connected LoRa controller.
Raspberry Pi Pico W	RP2040 board with CYW43439 wireless connectivity; typically 2MB flash. WiFi/Bluetooth can support network features when the firmware and project use them.
Raspberry Pi Pico 2	Newer RP2350 board; 520KB SRAM and typically 4MB flash; no WiFi or Bluetooth. It is not an RP2040 board, so firmware targets must match.
Raspberry Pi Pico 2 W	RP2350 board with CYW43439 wireless connectivity; typically 4MB flash. It combines the newer MCU with the W-series wireless hardware.
Waveshare Pico-LoRa-SX1262	Most common variant. SX1262 radio chip; 915MHz or 868MHz version. Plugs directly onto the Pico 40-pin header.
Waveshare SX1268 variant	433/470MHz version. Different chip, same interface. Check your regional frequency before ordering.
Antenna	Required — never transmit without an antenna. The Waveshare modules include a small antenna; an external omnidirectional 915MHz antenna improves range significantly.

What the Names Mean

The four names describe two separate choices:

Choice	Original generation	Second generation
Microcontroller	Pico / Pico W use RP2040	Pico 2 / Pico 2 W use RP2350
Wireless	Pico and Pico 2 have no built-in WiFi/Bluetooth	The W versions add WiFi/Bluetooth; the LoRa radio is still a separate SX126x device

Pico 2 boards keep the familiar Pico form factor and header layout, so a HAT may physically fit, but physical compatibility is not the same as firmware compatibility. Check the Waveshare documentation and the Meshtastic release assets for the exact board and radio combination.

For a simple USB-connected Meshtastic node, the non-W version is enough. Choose a W version only when the project needs WiFi or Bluetooth and the selected firmware supports it. The W does not change the LoRa frequency or make a 915 MHz board work on another band.

For the RP2040 Cortex-M0+ and Thumb assembly boundary behind Pico/Pico W projects, see Raspberry Pi Pico W Assembly: RP2040, Cortex-M0+, and Thumb.

Pin Connections (SX1262 to Pico)

The Waveshare Pico-LoRa-SX1262 plugs directly onto the Pico — no wiring needed if you use the HAT form factor. If you're using the SPI breakout version, these are the connections:

SX1262 Pin	Pico GPIO	Function
SCK	GPIO 10	SPI clock
MOSI	GPIO 11	SPI data out (Pico → radio)
MISO	GPIO 12	SPI data in (radio → Pico)
NSS / CS	GPIO 3	SPI chip select (active low)
RST	GPIO 15	Reset (active low)
BUSY	GPIO 2	Radio busy signal (wait when high)
DIO1	GPIO 20	Interrupt (TX done, RX done)
3.3V	3V3 OUT	Power
GND	GND	Ground

Waveshare's documentation and their example code uses these pins. If you use their HAT, these are pre-wired.

Hardware Checks Before Powering Up

The Pico and radio use 3.3 V logic. A wiring mistake can damage the RP2040 or the SX126x, so check the hardware before loading software:

• Confirm whether the board is the 433/470 MHz SX1268 version or the 868/915 MHz SX1262 version.
• Confirm that the antenna is connected before any transmit test.
• Use the HAT's documented power input and never feed 5 V into a 3.3 V GPIO.
• Check the HAT orientation and make sure the header pins are fully seated.
• Keep the radio away from loose metal objects while testing.

The pin table below describes the common Waveshare wiring, but the board revision and driver documentation are the final authority. Treat a breakout board and a direct-mount HAT as separate wiring jobs.

MicroPython Setup

# Flash MicroPython to the Pico:
# 1. Hold BOOTSEL button and plug in USB — appears as mass storage device
# 2. Download .uf2 for the exact board:
#    RPI_PICO for Pico / Pico W
#    RPI_PICO2 for Pico 2 / Pico 2 W
# 3. Copy the .uf2 to the drive — Pico reboots into MicroPython

# Connect with a serial terminal
$ minicom -D /dev/ttyACM0 -b 115200
# or: screen /dev/ttyACM0 115200
# or use Thonny IDE (easiest for beginners)

# On Debian, check which device appeared after plugging in the Pico
$ dmesg --follow
$ ls -l /dev/ttyACM*

Waveshare SX1262 MicroPython Library

# Waveshare provides example code on their wiki.
# Clone their examples or download the sx1262.py driver:
# https://www.waveshare.com/wiki/Pico-LoRa-SX1262

# Basic transmit example (MicroPython):

from machine import SPI, Pin
from sx1262 import SX1262   # Waveshare's driver

# SPI bus on Pico SPI1
spi = SPI(1,
    baudrate=2000000,
    polarity=0,
    phase=0,
    bits=8,
    firstbit=SPI.MSB,
    sck=Pin(10),
    mosi=Pin(11),
    miso=Pin(12)
)

sx = SX1262(spi,
    cs=Pin(3, Pin.OUT),
    irq=Pin(20, Pin.IN),
    rst=Pin(15, Pin.OUT),
    gpio=Pin(2, Pin.IN)
)

# Configure the radio
sx.begin(
    freq=915,           # MHz — match your region
    bw=125.0,           # kHz bandwidth
    sf=10,              # spreading factor (7-12)
    cr=5,               # coding rate 4/5
    syncWord=0x12,      # private network sync word (0x34 = public LoRaWAN)
    power=22,           # dBm TX power (max 22 on SX1262)
    currentLimit=140.0,
    preambleLength=8,
    implicit=False,
    implicitLen=0xFF,
    crcOn=True,
    txIq=False,
    rxIq=False,
    tcxoVoltage=1.7,
    useRegulatorLDO=False,
    blocking=True
)

# Transmit
message = "hello from pico"
sx.send(message.encode())
print("Sent:", message)

Radio Configuration Is a Contract

Every node that should communicate must agree on the radio parameters. Frequency, bandwidth, spreading factor, coding rate, sync word, and packet format all matter. A node can be perfectly wired and still appear dead when it is configured for another band or modem setting.

Before testing two nodes, write down:
  region / frequency: CA_915 for a Canadian 915 MHz setup
  bandwidth:          125 kHz
  spreading factor:   the same on both radios
  coding rate:        the same on both radios
  sync word:          the same on both radios
  antenna:            connected and matched to the band

The example driver call is illustrative; Waveshare libraries use slightly different class and argument names across releases. Start from the example shipped for your exact board, then change one setting at a time.

Receiving

import time

# Switch to receive mode
sx.recv(timeout_en=True, timeout_ms=5000)   # wait up to 5 seconds

while True:
    data, status = sx.recv()
    if data:
        print("Received:", bytes(data).decode("utf-8", errors="replace"))
        # RSSI and SNR from status:
        print(f"RSSI: {status[0]} dBm, SNR: {status[1]} dB")
    time.sleep(0.1)

Reading RSSI and SNR

RSSI (Received Signal Strength Indicator) and SNR (Signal-to-Noise Ratio) are essential for field troubleshooting:

Value	Meaning	What to do
RSSI > -90 dBm	Strong signal	Good — room to reduce SF or TX power to save battery
RSSI -90 to -110 dBm	Moderate signal	Acceptable — normal operating range for LoRa
RSSI -110 to -130 dBm	Weak signal	Increase SF or TX power; check antenna; adjust node placement
RSSI < -130 dBm	Very weak / near limit	Maximum SF12; consider relay node; antenna upgrade
SNR > 0 dB	Signal above noise floor	Comfortable margin
SNR -5 to 0 dB	Signal near noise floor	Marginal — packet loss likely under varying conditions
SNR < -10 dB	Below noise floor	LoRa can still decode (up to -20 dB margin) — but unreliable

Bench Test Before Meshtastic

Before adding batteries, enclosures, or a mesh, prove that the radio link works on the bench. Put the antennas a short distance apart, send numbered messages in both directions, and watch for missing sequence numbers. Then move one node farther away and repeat.

Test record:
  node A firmware / library version:
  node B firmware / library version:
  regional band:
  antenna type and orientation:
  message count sent:
  message count received:
  RSSI range:
  SNR range:
  supply voltage under transmit:

Do not judge a link only by RSSI. A strong-looking signal with a mismatched packet format still carries no usable data, and a lower RSSI with a stable SNR may be perfectly serviceable.

Power Consumption

Pico + SX1262 approximate current draw:

Mode            | Current  | Notes
----------------|----------|----------------------------------
Transmit (22dBm)| 120 mA   | Worst case; typical TX is brief
Receive         | 6 mA     | Continuously listening
Sleep (Pico+SX) | 0.5 mA   | Deep sleep both chips
Pico sleep only | 1.3 mA   | SX1262 still running

For battery-powered field nodes:
  - Transmit once per minute, sleep the rest: ~1-2 mA average
  - 2500 mAh battery → ~50-100 days battery life
  - Add a small solar panel + LiPo charger for indefinite operation

Transmit current is a peak, not the whole battery calculation. Measure the regulator output during transmission, include the sleep current of every sensor and charger, and leave capacity for cold weather and battery ageing. A power bank that shuts off at low current is not suitable for a node that sleeps most of the time.

The current table is an approximate RP2040-era reference, not a promise for every Pico revision. Pico W, Pico 2, and Pico 2 W have different wireless and MCU power characteristics. Measure the assembled board in its actual operating modes before sizing a field battery.

References

• Waveshare Pico-LoRa-SX1262 Wiki ↗
• MicroPython for Raspberry Pi Pico ↗
• Semtech SX1262 datasheet ↗