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Component Selection Guide

Parent Document: HARDWARE_OVERVIEW.md
Version: 0.2.0-draft

Microcontrollers​

Tier 1: ESP32-S3-WROOM-1-N8R8 (~€4.50)​

FeatureValue
CoreDual Xtensa LX7 @ 240 MHz
Memory8 MB Flash, 8 MB PSRAM
SecuritySecure Boot v2, Flash Encryption
WirelessWiFi 4 + BLE 5.0

Pros: Low cost, large community, hardware crypto
Cons: No TrustZone, limited side-channel resistance

Tier 2: STM32U585CIU6 (~€12)​

FeatureValue
CoreCortex-M33 @ 160 MHz
Memory2 MB Flash, 786 KB SRAM
SecurityTrustZone, OTFDEC, HUK, tamper pins
CryptoAES, SHA, PKA (DPA resistant)

Pros: TrustZone, PSA L3 ready, tamper inputs
Cons: Higher cost, needs external WiFi

Tier 3: STM32U5A9NJH6Q (~€18)​

Same security as U585 with 4 MB Flash, 2.5 MB SRAM, GPU.

Alternative MCUs​

PartFeaturesPriceUse Case
ESP32-C6RISC-V, WiFi 6, PSA L2~€3Budget WiFi coprocessor
nRF5340Dual CM33, BLE 5.3, Thread~€6BLE mesh primary
LPC55S69Dual CM33, PUF, TrustZone~€8Alternative to STM32

Secure Elements​

ATECC608B (~€0.90) - All Tiers​

FeatureValue
AlgorithmsECC-P256, SHA-256, AES-128
Key Slots16
InterfaceI²C

Use: Identity key, TLS client, secure boot verification

OPTIGA Trust M (~€3) - Tier 2+​

FeatureValue
AlgorithmsECC P-256/384/521, RSA-2048
CertificationCC EAL6+
InterfaceShielded I²C

Use: Message keys, session management (different vendor)

NXP SE050 (~€5) - Tier 3​

FeatureValue
Storage50 KB secure
CertificationCC EAL6+, FIPS 140-2 L3 (variant)
InterfaceI²C + NFC provisioning

Use: Backup/recovery, third vendor redundancy

Comparison Matrix​

FeatureATECC608BOPTIGA Trust MSE050
Price€0.90€3€5
ECC-P256✓✓✓
ECC-P384/521✗✓✓
RSA✗✓✓
CC Certification✗EAL6+EAL6+
FIPS 140-2✗✗L3 (variant)

Displays​

LCD Options​

PartResolutionInterfacePriceUse Case
ST7789V 2.4"320×240SPI€8Tier 1 handheld
ILI9341 3.2" + Touch320×240SPI + I²C€15Tier 2 handheld
ILI9488 3.5"480×320SPI/Parallel€20Tier 3 premium

E-Ink Options​

PartResolutionRefreshPriceUse Case
Waveshare 2.9"296×1282s full, 0.3s partial€18Tier 1 pager
GDEY042T81 4.2"400×3001.5s full, 0.3s partial€28Tier 2-3 pager
GDEY075T7 7.5"800×4802s full€45Desktop/wall mount

Connectivity​

WiFi Modules​

ModuleStandardPriceNotes
ESP32-S3 (integrated)WiFi 4-Built into Tier 1 MCU
ESP32-C6-MINI-1WiFi 6€4Coprocessor for STM32, TWT support
ESP32-C3-MINI-1WiFi 4€2.50Budget coprocessor

LoRa / Sub-GHz Radio​

Point-to-Point & Mesh (Meshtastic Compatible)​

Infrastructure-independent communication for field use.

ModuleChipFrequencyPowerRangePrice
E22-900M30SSX1262868/915 MHz+30 dBm (1W)10-15 km€8
E22-400M30SSX1262433 MHz+30 dBm (1W)15-20 km€8
RFM95WSX1276868/915 MHz+20 dBm5-10 km€5
E220-900M22SLLCC68868/915 MHz+22 dBm5-8 km€4
Ra-01HSX1262868/915 MHz+22 dBm8-12 km€5

Use Case:

  • Direct device-to-device messaging
  • Mesh networks via Meshtastic protocol
  • No cellular/internet infrastructure needed
  • Emergency/backup communication channel

LoRaWAN (Network Infrastructure)​

For integration with existing LoRaWAN networks or building your own gateway infrastructure.

LoRaWAN End Nodes​

ModuleChipClassPriceNotes
RAK3172STM32WLE5A/B/C€8Integrated MCU + LoRa
E5-MiniSTM32WLE5A/B/C€12Seeed module, FCC/CE certified
RN2483A-A€15Microchip, mature ecosystem
SX1302SX1302Gateway€40Multi-channel gateway chip

LoRaWAN Gateway Mode​

SimpleGo devices can optionally operate as LoRaWAN Gateways, bridging LoRa messages to the internet:

┌─────────────────────────────────────────────────────────────────────────────┐
│                      SIMPLEGO AS LORAWAN GATEWAY                            │
├─────────────────────────────────────────────────────────────────────────────┤
│                                                                             │
│    FIELD DEVICES                    GATEWAY                    CLOUD       │
│                                                                             │
│   ┌───────────┐                 ┌─────────────┐           ┌─────────────┐  │
│   │ SimpleGo  │    LoRa         │  SimpleGo   │   4G/5G   │   SimpleX   │  │
│   │  Pager 1  │ ──────────────► │   Gateway   │ ────────► │   Server    │  │
│   └───────────┘    868 MHz      │   Device    │   or      └─────────────┘  │
│                                 │             │   WiFi                      │
│   ┌───────────┐                 │ ┌─────────┐ │                             │
│   │ SimpleGo  │ ──────────────► │ │SX1302/  │ │                             │
│   │  Pager 2  │                 │ │SX1262   │ │                             │
│   └───────────┘                 │ └─────────┘ │                             │
│                                 │             │                             │
│   ┌───────────┐                 │ ┌─────────┐ │                             │
│   │ SimpleGo  │ ──────────────► │ │ 4G/5G   │ │                             │
│   │  Pager 3  │                 │ │ Modem   │ │                             │
│   └───────────┘                 │ └─────────┘ │                             │
│                                 └─────────────┘                             │
│                                                                             │
│   Range: 2-15 km per gateway (depends on terrain)                          │
│   Capacity: 1000s of end devices per gateway                               │
│                                                                             │
└─────────────────────────────────────────────────────────────────────────────┘

Gateway Hardware Options​

ConfigurationComponentsCostCapacityUse Case
Single-ChannelSX1262 + ESP32€15~50 devicesPersonal/small group
8-ChannelSX1302 + ESP32/RPi€60~1000 devicesCommunity gateway
Full GatewayRAK2287 + RPi€150~10000 devicesPublic infrastructure

LoRaWAN Gateway Modules​

ModuleChannelsInterfacePriceNotes
RAK22878SPI (mini-PCIe)€80Best for RPi, GPS included
RAK51468SPI/USB€90USB version available
SX1302CSSXXXGW18Reference design€100Semtech eval board
SX1303 + SX12508SPI€50DIY gateway

Gateway Software Stack​

┌─────────────────────────────────────────┐
│         SimpleGo Application            │
│      (Message routing, encryption)      │
├─────────────────────────────────────────┤
│         ChirpStack Gateway Bridge       │  ← Or custom implementation
│         (LoRaWAN packet forwarder)      │
├─────────────────────────────────────────┤
│         SX1302 HAL / Driver             │
├─────────────────────────────────────────┤
│         SPI Interface                   │
└─────────────────────────────────────────┘

Gateway Mode Features:

  • Forward encrypted SimpleGo messages from LoRa to internet
  • Can connect to public TTN (The Things Network) or private server
  • Supports Class A, B, C devices
  • 8-channel gateway supports 1000+ devices
  • Can run on Tier 2/3 devices with cellular backhaul

Frequency Plans​

RegionFrequencyChannelsMax Power
EU868863-870 MHz8+14 dBm (25 mW)
US915902-928 MHz64+8+26 dBm (400 mW)
AU915915-928 MHz64+8+26 dBm
AS923923 MHz8+16 dBm
IN865865-867 MHz3+30 dBm

Cellular Modules​

LTE Cat-M / NB-IoT (Low Power IoT)​

Best for battery-powered devices with infrequent messaging.

ModuleBandsData RatePriceNotes
Quectel BG95-M3Global LTE-M/NB-IoT375 kbps~€18GPS included, low power
Quectel BG96Global LTE-M/NB-IoT375 kbps~€20Mature, well documented
nRF9160 SiPGlobal LTE-M/NB-IoT375 kbps~€22Integrated MCU + TrustZone, PSA L2
SIM7080GGlobal LTE-M/NB-IoT375 kbps~€12Budget option

Power Consumption:

  • Idle (PSM): 1-3 µA
  • Idle (eDRX): 1-3 mA
  • Active TX: 200-400 mA

4G LTE Cat 4 (Full Speed Mobile Broadband)​

Best for real-time messaging, media transfer, and gateway operation.

ModuleBandsData RatePriceNotes
Quectel EC25-ELTE Cat 4 (EU)150/50 Mbps~€25Best for Europe
Quectel EG25-GLTE Cat 4 (Global)150/50 Mbps~€28Worldwide, recommended
SIM7600E-HLTE Cat 4 (EU)150/50 Mbps~€22Good Linux/RPi support
SIM7600G-HLTE Cat 4 (Global)150/50 Mbps~€30All regions
Quectel EC21LTE Cat 110/5 Mbps~€18Lower power than Cat 4

Power Consumption:

  • Idle: 10-20 mA
  • Active TX: 500-800 mA
  • Peak: 2A (ensure power supply can handle)

4G LTE Cat 6/12 (High Speed)​

For gateway applications requiring higher bandwidth.

ModuleBandsData RatePriceNotes
Quectel EC200A-EULTE Cat 4150/50 Mbps~€15Cost-optimized
Quectel EM06-ELTE Cat 6300/50 Mbps~€40M.2 form factor
Quectel EM12-GLTE Cat 12600/150 Mbps~€55Carrier aggregation

5G Modules (Future-Proof / Maximum Performance)​

For Tier 3 premium devices, gateways, and future-proofing.

ModuleTechnologyData RatePriceNotes
Quectel RM500Q-GL5G Sub-6 GHz2.1 Gbps / 900 Mbps~€80-100NSA/SA, recommended
Quectel RM500U-CN5G Sub-6 GHz2.1 Gbps / 900 Mbps~€70China bands
Quectel RM520N-GL5G Sub-6 + mmWave4.2 Gbps / 900 Mbps~€120-150Maximum speed
SIM8262E-M25G Sub-6 GHz2.4 Gbps / 500 Mbps~€90M.2 form factor
Fibocom FM160-EAU5G Sub-6 GHz2.1 Gbps / 900 Mbps~€85Good EU availability
Fibocom FG360-EAU5G Sub-6 GHz2.1 Gbps / 500 Mbps~€95Industrial grade

Power Consumption:

  • Idle: 20-50 mA
  • Active TX: 1-2 A
  • Peak: 3-4 A (requires robust power design!)

Cellular Module Comparison​

TypeLatencyBattery LifeCostBest For
LTE-M/NB-IoT100-500msWeeks-Months€12-22Pagers, sensors
4G Cat 150-100msDays€18-25Basic messaging
4G Cat 430-50msHours-Day€22-30Real-time messaging, small gateway
4G Cat 6/1220-40msHours€40-55High-capacity gateway
5G Sub-610-20msHours€70-100Premium devices, high-cap gateway
5G mmWave1-10msHours€120-150Maximum performance gateway

Cellular Security Considerations​

┌─────────────────────────────────────────────────────────────────┐
│              CELLULAR MODULE ISOLATION                          │
├─────────────────────────────────────────────────────────────────┤
│                                                                 │
│  ⚠️  ALL cellular modules have CLOSED-SOURCE baseband firmware  │
│      Treat the modem as UNTRUSTED / potentially hostile         │
│                                                                 │
│  REQUIRED MITIGATIONS:                                          │
│                                                                 │
│  1. Physical isolation                                          │
│     ┌─────────────┐      ┌─────────────┐                       │
│     │   MAIN MCU  │ UART │   MODEM     │                       │
│     │  (trusted)  │◄────►│ (untrusted) │                       │
│     │             │      │             │                       │
│     │  TLS 1.3    │      │  Baseband   │                       │
│     │  endpoint   │      │  firmware   │                       │
│     └─────────────┘      └─────────────┘                       │
│           │                    │                                │
│     Separate power        Can be powered                       │
│     domain                down when not needed                 │
│                                                                 │
│  2. Network-level security                                      │
│     - TLS 1.3 for ALL data (assume network is hostile)         │
│     - Certificate pinning for SimpleX servers                  │
│     - No sensitive data in SMS/USSD                            │
│                                                                 │
│  3. Best practice: nRF9160                                      │
│     - TrustZone isolation between app and modem                │
│     - PSA Level 2 certified                                    │
│     - App processor can't access modem internals               │
│                                                                 │
└─────────────────────────────────────────────────────────────────┘

SIM Options​

TypeDescriptionUse Case
Nano-SIM slotPhysical SIM cardStandard, user-swappable
eSIM (eUICC)Embedded, remote provisioningNo physical access needed
Dual SIMTwo slots or SIM + eSIMRedundancy, travel
Multi-IMSI SIMSingle SIM, multiple profilesGlobal roaming

Recommendations:

  • Tier 1-2: Nano-SIM slot (simple, user-controlled)
  • Tier 3: eSIM + Nano-SIM slot (redundancy + remote provisioning)

Antenna Requirements​

TechnologyAntenna SizeBandsNotes
LoRaSmall PCB or whip433/868/915 MHzExternal SMA recommended
LTE-M/NB-IoTSmall PCB antenna700-2100 MHzCompact designs OK
4G LTEMedium, external recommended700-2700 MHzConsider external SMA
5G Sub-6Medium-Large600-6000 MHzExternal antenna recommended
5G mmWaveAntenna array24-40 GHzSpecialized design required

Satellite Communication (Last Resort)​

For truly infrastructure-independent messaging.

ModuleNetworkCoverageMessage SizePriceNotes
Swarm M138SwarmGlobal192 bytes~€100VHF, low power
RockBLOCK 9603IridiumGlobal340 bytes~€200Proven, higher power
L-band modulesStarlinkTBDTBDTBDFuture option

Use Case: Tier 3 emergency fallback, remote areas, censorship circumvention

Tamper Detection​

ComponentFunctionPrice
DS3645Tamper supervisor (8 inputs)€22
APDS-9960Light + proximity sensor€3
23LC1024Battery-backed SRAM€2
DS1321SRAM supervisor€4

Power Management​

ComponentFunctionPrice
TP4056Basic Li-Ion charger€0.50
AXP2101Full PMIC + fuel gauge€3
BQ25895High-current charger (5A)€4
MP2759USB-C PD sink controller€2
Tadiran TL-590220-year backup battery€8

Power Budget Examples​

ConfigurationIdleActivePeakBattery Life (3000mAh)
WiFi only20 mA150 mA400 mA2-3 days active
WiFi + LoRa25 mA250 mA500 mA1-2 days active
WiFi + LTE-M25 mA300 mA600 mA1-2 days active
WiFi + 4G LTE35 mA600 mA2 A8-12 hours active
WiFi + 5G50 mA1.2 A4 A4-6 hours active
Gateway (LoRa + 4G)100 mA800 mA3 A4-8 hours (needs mains power)

Note: 5G and gateway operation require robust power design - minimum 4A capability!

Sourcing Guidelines​

Authorized Distributors Only​

  • DigiKey, Mouser, Arrow, Farnell, RS Components

Specialized Sources​

Component TypeRecommended Source
General ICsDigiKey, Mouser
Quectel modulesDigiKey, Quectel Direct
SIMCom modulesSIMCom Direct, Mouser
Nordic (nRF)DigiKey, Nordic Direct
LoRa modulesEBYTE Direct, DigiKey
RAK modulesRAKwireless Store

Never Source From​

  • AliExpress (for production)
  • eBay, unknown brokers
  • Unauthorized resellers (counterfeit risk)

Quick Reference​

MCUs:
  ESP32-S3-WROOM-1-N8R8      Tier 1
  STM32U585CIU6              Tier 2
  STM32U5A9NJH6Q             Tier 3

Secure Elements:
  ATECC608B-SSHDA-B          All tiers (primary)
  SLS32AIA010MH              Tier 2+ (OPTIGA)
  SE050E                     Tier 3 (NXP)

LoRa:
  E22-900M30S (SX1262)       Point-to-point, mesh
  RAK3172                    LoRaWAN end node
  RAK2287 / SX1302           LoRaWAN gateway (8-ch)

Cellular:
  BG95-M3 / nRF9160          LTE-M/NB-IoT (low power)
  EG25-G / SIM7600G-H        4G LTE Cat 4 (global)
  RM500Q-GL                  5G Sub-6 (premium)
  RM520N-GL                  5G Sub-6 + mmWave (max)

Tamper:
  DS3645+                    Tier 3 supervisor
  APDS-9960                  Light sensor
  23LC1024-I/SN              Battery-backed SRAM