Microcontrollers and Modems

Microcontrollers (MCUs)

1. ESP32 / ESP32-S3

Feature	Detail
Architecture	Xtensa LX6 dual-core @ 240 MHz (ESP32); LX7 dual-core @ 240 MHz (S3)
RAM	520 KB SRAM (ESP32); 512 KB + optional PSRAM (S3)
Flash	External, typically 4–16 MB
Wi-Fi	802.11 b/g/n 2.4 GHz — yes on both
Bluetooth	BT Classic + BLE 4.2 (ESP32); BLE 5.0 (S3)
GPIO	34 pins (ESP32); 45 pins (S3)
ADC/DAC	18× ADC, 2× DAC (ESP32); 20× ADC (S3)
USB	Requires CP2102/CH340 bridge (ESP32); native USB on S3
Sleep Current	~10 µA deep sleep; ~40–80 mA typical active RX
Operating Voltage	3.0–3.6 V
Price Range	Low (~$2–$8 module)

Notes: Most widely used MCU in Meshtastic hardware. Wi-Fi enables MQTT bridging and web UI, but significantly higher power draw than nRF52840 makes it unsuitable for solar or long-term battery nodes. No native USB on classic ESP32.

2. nRF52840

Feature	Detail
Architecture	ARM Cortex-M4F @ 64 MHz
RAM	256 KB SRAM
Flash	1 MB internal
Wi-Fi	None
Bluetooth	BLE 5.0 + Bluetooth Mesh + NFC
GPIO	48 pins
ADC	8× 12-bit SAR ADC
USB	Native USB 2.0 Full Speed
Sleep Current	~2 µA deep sleep; as low as ~11 µA in typical Meshtastic standby
Operating Voltage	1.7–5.5 V
Price Range	Mid (~$10–$20 module)

Notes: Best-in-class power efficiency — Meshtastic strongly recommends it for solar and handheld applications. Native USB with UF2 drag-and-drop flashing. No Wi-Fi means no web UI without external hardware.

3. STM32WL / STM32WB (ARM Cortex-M4)

Feature	Detail
Architecture	ARM Cortex-M4 @ 48 MHz + Cortex-M0+ radio coprocessor (WL); dual Cortex-M4 (WB)
RAM	64–256 KB SRAM
Flash	256 KB – 1 MB internal
Wi-Fi	None
Bluetooth	BLE 5.0 (STM32WB only)
Sub-GHz Radio	Integrated SX1262-compatible LoRa/FSK radio (STM32WLE5)
GPIO	20–73 pins depending on variant
ADC	12-bit multi-channel ADC
USB	Full Speed on select variants
Sleep Current	~300 nA shutdown; ~2 µA standby
Operating Voltage	1.71–3.6 V
Price Range	Mid (~$5–$15 chip)

Notes: STM32WLE5 integrates an SX1262-equivalent LoRa radio on-die, eliminating the external radio chip — smaller PCB, lower BOM cost. Ultra-low shutdown current and hardware AES-256. Steeper toolchain (STM32CubeIDE), limited Meshtastic community support, and UFBGA package is difficult to hand-solder.

4. ARM + Linux SoC (e.g. Raspberry Pi / CM4)

Feature	Detail
Architecture	ARM Cortex-A53/A72 @ 1.5–2.4 GHz
RAM	512 MB – 8 GB
Storage	microSD / eMMC
Wi-Fi	802.11ac dual-band (Pi 4/5, CM4)
Bluetooth	BLE 5.0
USB	USB 2.0 + USB 3.0
GPIO	40-pin header
OS	Full Linux (Debian / Raspberry Pi OS)
Idle Power	~600 mA – 2+ A @ 5 V
Boot Time	20–60 seconds

Notes: Best treated as a fixed gateway or router node. Runs Meshtastic as a meshtasticd daemon alongside MQTT, web servers, and automation scripts. High continuous power draw and boot latency make battery operation and sleep/wake cycles impractical. Requires an external LoRa HAT.

LoRa Modems

Generation overview: Semtech has released multiple generations of LoRa silicon. Gen 1 (SX127x) is legacy. Gen 2 (SX126x) is the current mainstream recommended family. Gen 3 (LR11xx) adds multi-band and geolocation. The STM32WLE5 integrates a Gen 2-equivalent radio directly on the MCU die.

1. SX1262 / SX1268 — Gen 2 (Recommended)

Feature	Detail
Frequency Bands	SX1262: 150–960 MHz (868/915 MHz focus); SX1268: 410–810 MHz (433/470 MHz focus)
Modulation	LoRa, (G)FSK, BPSK
Max TX Power	+22 dBm
Receive Sensitivity	–148 dBm @ SF12, 125 kHz BW
Spreading Factors	SF5–SF12
Bandwidth	7.8–500 kHz
Max Air Data Rate	~62.5 kbps (LoRa mode)
Interface	SPI
Supply Voltage	1.8–3.7 V
RX Current	~4.6 mA
TX Current	~118 mA @ +22 dBm
Sleep Current	~900 nA
Package	QFN-24 (4×4 mm)

Notes: The dominant modem in current Meshtastic hardware — strongly recommended for all new builds. Roughly half the RX current of SX127x, +2 dBm more TX power, higher data rate, smaller package, and lower supply voltage. SX1262 and SX1268 are pin-compatible and share the same driver. SX1261 is a lower-output sibling (+15 dBm max) used in ultra-low-power designs.

2. SX1276 / SX1278 — Gen 1 (Legacy)

Feature	Detail
Frequency Bands	SX1276: 137–1020 MHz; SX1278: 137–525 MHz
Modulation	LoRa, (G)FSK, OOK
Max TX Power	+20 dBm
Receive Sensitivity	–148 dBm @ SF12, 125 kHz BW
Spreading Factors	SF6–SF12
Bandwidth	7.8–500 kHz
Max Air Data Rate	~37.5 kbps (LoRa mode)
Interface	SPI
Supply Voltage	3.3 V
RX Current	~10–12 mA
TX Current	~120 mA @ +20 dBm
Sleep Current	~200 nA
Package	QFN-28 (6×6 mm)

Notes: Still found on early T-Beam and first-generation Heltec boards. Functional and inter-operable with SX126x nodes, but Meshtastic actively discourages new builds with these chips — lower efficiency PA, higher RX current, 3.3 V only, and larger package than SX126x.

3. SX1280 — Gen 2 (2.4 GHz)

Feature	Detail
Frequency Band	2.400–2.500 GHz
Modulation	LoRa, (G)FSK, FLRC, BLE advertising compatible
Max TX Power	+12–13 dBm (standard); +20 dBm with external PA (used on T-Beam Supreme)
Receive Sensitivity	–132 dBm @ SF12, 203 kHz BW (LoRa)
Spreading Factors	SF5–SF12
Max Air Data Rate	1.6 Mbps (FLRC mode)
Interface	SPI
Supply Voltage	1.8–3.7 V
RX Current	~5.4 mA
Sleep Current	~900 nA
Package	QFN-24

Notes: Operates on the globally license-free 2.4 GHz ISM band — useful for international deployments without frequency planning. Reduced range vs. sub-GHz LoRa (2.4 GHz penetrates walls and foliage less effectively), but well-suited for high-density, short-range mesh. FLRC mode enables very high data rates. Used on the LILYGO T3S3 and T-Beam Supreme with PA.

4. LR1110 / LR1120 / LR1121 — Gen 3 (Multi-band + Geolocation)

Feature	Detail
Frequency Bands	150–960 MHz sub-GHz + 2.4 GHz ISM; LR1120/1121 also add S-band (1.9–2.1 GHz satellite); LR1121 adds L-band (1.55 GHz)
Modulation	LoRa, (G)FSK, BPSK, LR-FHSS
Max TX Power	+22 dBm (sub-GHz HP path); +15 dBm (LP path); +13 dBm (2.4 GHz / S-band)
Receive Sensitivity	–148 dBm @ SF12, 125 kHz BW — identical to SX1262
Spreading Factors	SF5–SF12
Interface	SPI (up to 16 MHz)
Supply Voltage	1.8–3.7 V
Sleep Current	~900 nA
Package	QFN-40
On-chip GNSS	Multi-constellation scanner (GPS, BeiDou) + passive Wi-Fi AP MAC scanner for cloud-assisted geolocation
SX1262 Compatible	Yes — air interface fully compatible with SX1261/2/8 family

Notes: Supported and growing. The defining feature is the on-chip GNSS and Wi-Fi scanning engine, enabling low-power position fixes without a dedicated GPS module — used in the SenseCAP T1000-E card tracker and Elecrow ThinkNode M3. LR1110 = sub-GHz + 2.4 GHz; LR1120 adds S-band satellite; LR1121 adds L-band on top. Important: LR11xx nodes cannot receive packets from legacy SX127x (Gen 1) devices.

5. STM32WLE5 Integrated Radio — Gen 2 (SoC)

Feature	Detail
Frequency Bands	150–960 MHz
Modulation	LoRa, (G)FSK, BPSK, OOK
Max TX Power	+22 dBm (HP path); +15 dBm (LP path)
Receive Sensitivity	–148 dBm @ SF12, 125 kHz BW
Spreading Factors	SF5–SF12
Radio Architecture	SX1262-compatible IP licensed from Semtech, running on dedicated Cortex-M0+ radio processor
Sleep Current	~300 nA shutdown (entire SoC including MCU)
Package	UFBGA73 or QFN48
SX1262 Compatible	Yes

Notes: SX1262-equivalent RF performance in a single-chip SoC — eliminates the external radio, SPI bus, and RF matching network entirely. Best suited for compact custom hardware. Limited Meshtastic community support; main barrier is STM32 toolchain complexity.

Summary Tables

MCUs

	ESP32	ESP32-S3	nRF52840	STM32WL/WB	ARM+Linux
Wi-Fi	✅	✅	❌	❌	✅
BLE	4.2	5.0	5.0	5.0 (WB)	5.0
Native USB	❌	✅	✅	Varies	✅
Battery Life	Medium	Medium	Best	Excellent	Worst
Meshtastic Support	Best	Best	Good	Limited	Good (daemon)
Cost	Low	Low	Mid	Mid	High
Best Use Case	MQTT gateway, indoor	Gateway, touchscreen UI	Solar, handheld	Custom hardware	Fixed router

LoRa Modems

	SX1262/68	SX1276/78	SX1280	LR1110–1121	STM32WLE5
Generation	Gen 2	Gen 1	Gen 2	Gen 3	Gen 2 (SoC)
Frequency	Sub-GHz	Sub-GHz	2.4 GHz	Sub-GHz + 2.4 GHz (+ satellite)	Sub-GHz
Sensitivity	–148 dBm	–148 dBm	–132 dBm	–148 dBm	–148 dBm
Max TX	+22 dBm	+20 dBm	+13 dBm (+20 w/PA)	+22 dBm	+22 dBm
RX Current	~4.6 mA	~12 mA	~5.4 mA	~4.6 mA	~4.6 mA
On-chip GNSS	❌	❌	❌	✅	❌
External chip needed	Yes	Yes	Yes	Yes	No (on-die)
SX127x compatible	✅	—	❌	❌	✅
Meshtastic status	Recommended	Legacy	Niche	Growing	Limited

Pre-Built Nodes

If you prefer a simpler option, consider pre-built devices such as the Heltec V3/V4, WisMesh Pocket V2 / Tag, or T-Echo, many of which include a case.