Microcontrollers & Modems

Microcontrollers (MCUs)

ESP32 / ESP32-S3

• Best for: MQTT gateways, portable nodes
• Pros: 2.4 GHz WiFi
• Cons: Higher power draw
• Cost: Low (~$2–$8 module)

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)
Sleep Current	~10 µA deep sleep; ~40–80 mA typical active RX
Operating Voltage	3.0–3.6 V
USB	Requires CP2102/CH340 bridge (ESP32); native USB on S3

nRF52840

• Best for: Solar/battery-powered handhelds
• Pros: Exceptional power efficiency (~2 µA deep sleep)
• Cons: No Wi-Fi, mid-tier pricing
• Cost: Mid (~$10–$20 module)

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
Sleep Current	~2 µA deep sleep; as low as ~11 µA in typical Meshtastic standby
Operating Voltage	1.7–5.5 V
USB	Native USB 2.0 Full Speed

SBC / Linux SoC

• Best for: Fixed gateway/router nodes, MQTT bridges, automation
• Pros: Full Linux OS, Wi-Fi/Bluetooth, can run Meshtastic daemon + other services
• Cons: High continuous power draw (600 mA – 2+ A @ 5 V), impractical for battery/sleep cycles
• Cost: High

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
Idle Power	~600 mA – 2+ A @ 5 V
Requires	External LoRa HAT

LoRa Modems

SX1262 / SX1268 (Sub-GHz, Recommended)

• Pros: Higher TX power, more efficient, smaller package

Feature	Detail
Frequency Bands	SX1262: 868/915 MHz; SX1268: 433/470 MHz
Range	–148 dBm sensitivity @ SF12, 125 kHz BW
Power	~4.6 mA RX, ~118 mA TX @ +22 dBm, 900 nA sleep
Max TX Power	+22 dBm
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
Package	QFN-24 (4×4 mm)

SX1276 / SX1278 (Legacy, Sub-GHz)

• Status: Legacy (still supported but not recommended)
• Why: Higher RX current, larger package, 3.3V only

Feature	Detail
Frequency Bands	SX1276: 137–1020 MHz; SX1278: 137–525 MHz
Range	–148 dBm sensitivity @ SF12, 125 kHz BW
Power	~10–12 mA RX, ~120 mA TX @ +20 dBm
Max TX Power	+20 dBm
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
Package	QFN-28 (6×6 mm)

GNSS

L76K (Quectel)

• Pros: Low cost (~$2–5), minimal power draw, compact form factor
• Cons: Lower accuracy in urban canyons, less satellite constellation support

Feature	Detail
Positioning Support	GPS, BeiDou, GLONASS
Positioning Accuracy	Standard precision (1-5 meters)
Acquisition	-148 dBm
Re-Acquisition	-160 dBm
Tracking	-162 dBm
Position Accuracy (CEP)	2.0 meters
Speed Accuracy	0.1 m/s
Update Rate	5 Hz (configurable)
Warm Start	~5–15 seconds
Cold Start	~35 seconds

u-blox (NEO-M8 / NEO-M9 Series)

• Pros: Superior multi-constellation support, faster acquisition, better urban canyon performance, widely supported
• Cons: Higher cost (~$10–20), larger footprint, slightly higher power draw

Feature	Detail
Positioning Support	GPS, BeiDou, GLONASS, Galileo (multi-constellation)
Positioning Accuracy	High precision (1–2.5 meters, 1–5 meters urban)
Acquisition	-150 dBm
Re-Acquisition	-163 dBm
Tracking	-166 dBm
Position Accuracy (CEP)	1.0–1.5 meters
Speed Accuracy	0.05 m/s
Update Rate	10 Hz (configurable)
Warm Start	~2–5 seconds
Cold Start	~15–25 seconds

Quick Comparison

	L76K	u-blox
Cost	$2–5	$10–20
Accuracy (CEP)	2.0 m	1.0–1.5 m
Constellations	3 (GPS/BeiDou/GLONASS)	4 (adds Galileo)
Cold Start	~35 s	~15–25 s
Urban Performance	Moderate	Excellent
Power (active)	30–50 mA	40–70 mA
Best Use	Budget builds, moderate precision	Precision required, difficult environments