2 layers76 × 35 mm
Ground station
Horizon-Avionics/Horizon-H1
Building a fully open-source flight computer for amateur rocketry!
38 parts17
4 layers30.5 × 72.9 mm
Topaz
dfedor2008/TopazA radio module which can send data through morse code
- Size
- 30.5 × 72.9 mm
- Copper layers
- 4
- Thickness
- 1.22 mm
- Parts
- 60
- Nets
- 79
- Pads
- 255
- Tracks, vias
- 455, 234
- Pours
- 3
- Routed
- Yes
- KiCad
- KiCad 8.0 (file 20240108)
- Created
- 29 May 2025
- Updated
- 3 Aug 2025
Overview
Topaz is an open-source printed circuit board by dfedor2008, from the dfedor2008/Topaz repository on GitHub. It is a 4-layer board of 30.5 × 72.9 mm with 60 parts on 79 nets, routed with 455 tracks and 234 vias.
It is built around the ATSAMD21G18A-AU, PE4259-63 and SX1262IMLTRT, with the BME280, AMS1117-3.3 and 1N4148WT among its other parts. Its parts include 22 capacitors, 11 resistors, 7 ICs, 5 inductors and 3 diodes. It belongs with the radio and wireless boards and the SAM D and SAM boards of this library.
Main components
9
ATSAMD21G18A-AU
TQFP-48-40℃~+85℃ 1.62V~3.6V 10bit 12bit 256KB 32 Bit 32KB 38 48MHz ARM Cortex-M0+ Built-in FLASH 上电复位(POR)、欠压检测(BOR/LVD/LVR/LVI)、看门狗复位、内置通用定时器、硬件CRC、日历功能、触控功能 TQFP-48(7x7) Microcontrollers (MCU/MPU/SOC) ROHSMicrochip TechnologyMicrocontrollers (MCU/MPU/SOC)
PE4259-63
SC-70-6-40℃~+85℃ 0.35dB 1.8V~3.3V 10MHz~3GHz 30dB 33.5dBm Integrated control logic SPDT SC-70-6 RF Switches ROHSpSemiRF Switches
SX1262IMLTRT
QFN-24-EP(4x4)-148dBm -40℃~+85℃ 1.8V~3.7V 150MHz~960MHz 22dBm 300Kbps 32mA 4.2mA ISM SPI Supports software reset、Power-on reset function、Supports RSSI function transceiver QFN-24-EP(4x4) RF Transceiver ICs ROHSSEMTECHRF Transceiver ICs
BME280
LGA-8(2.5x2.5)-40℃~+85℃ 0%RH~100%RH 1.71V~3.6V 1.8uA 16bit I2C、SPI ±0.5℃ ±3%RH LGA-8(2.5x2.5) Temperature and Humidity Sensor ROHSBoschTemperature And Humidity Sensor
AMS1117-3.3
SOT-223-40℃~+125℃ 0.003%Vout 1 1.1V@(800mA) 15V 1A 3.3V 5mA 72dB@(120Hz) Fixed Over Current Protection、Short Circuit Protection、Thermal shutdown Positive SOT-223 Voltage Regulators - Linear, Low Drop Out (LDO) Regulators ROHSAdvanced Monolithic SystemsVoltage Regulators - Linear, Low Drop Out (LDO) Regulators
1N4148WT
SOD-523-55℃~+150℃ 1.25V@150mA 100V 150mA 150mW 1uA@75V 2A 4ns Independent SOD-523 Switching Diodes ROHShongjiachengSwitching Diodes
0900FM15K0039E
SMD-10P,1.2x2mmSMD-10P,1.2x2mm Ceramic Filters ROHSJohanson DielectricsCeramic Filters1575AT43A0040E
-- Antennas ROHSJohanson DielectricsAntennas
FA-128 32.0000MF20X-K5
SMD2016-4P-40℃~+85℃ 10pF 32MHz 60Ω Crystal Oscillator ±10ppm ±20ppm SMD2016-4P Crystals ROHSSeiko EpsonCrystals
README
README.mdTopaz - A Lightweight Long-Range GPS Telemetry System
What is Topaz?
Topaz is a compact, cost-effective GPS telemetry platform designed for long-range data transmission using LoRa modulation. It supports both Morse code and binary telemetry formats and integrates environmental sensing, making it suitable for high-altitude ballooning, rocket recovery, remote monitoring, and more.
Features & Components
- Microcontroller — ATSAMD21G18A: A reliable, low-power Cortex-M0+ MCU from Microchip.
- LoRa Radio — SX1262: Sub-GHz long-range radio for Morse or telemetry data.
- GPS Receiver — ATGM336H: Provides position and timing data.
- Environmental Sensor — BME280: Measures temperature, humidity, and pressure.
- Power Supply — Designed to run from USB or external LiPo/boosted AA battery (3.3V).
Use Cases
- Tracker for rockets
- Tracking for general uses
- Environmental monitoring (bme sensor)
How It Works
- The ATGM336H GPS module gathers location and time.
- The BME280 reads environmental parameters.
- The SAMD21 processes the data.
- The SX1262 transmits the payload via LoRa (in Morse or binary formats).
- A paired Topaz device or SDR can receive and decode the transmission.
All firmware is written in C++
Hardware Setup Guide
- Solder the PCB — A reflow plate is recommended for clean results.
- Inspect for Shorts — Pay extra attention around power and MCU pins.
- Power Up via External Supply (not USB) — Watch for smoke or abnormal heat. Power off immediately if detected.
- Connect via USB — Once verified safe, plug into your computer.
After soldering and testing, upload the firmware via Arduino IDE. Topaz is optimized for affordability and robustness.
PCB Diagrams
Schematic
Layout
Software & Configuration
This project uses the Arduino platform. Libraries include:
- TinyGPS++
- Adafruit_BME280
- RadioHead or LoRa drivers for SX1262
Parts
60| Qty | Value | Footprint | References |
|---|---|---|---|
| 4 | MountingHole_Pad | MountingHole:MountingHole_2.1mm | H1, H2, H3, H4 |
| 3 | 1nF | Capacitor_SMD:C_0402_1005Metric | C7, C12, C13 |
| 2 | 1.8k | Resistor_SMD:R_0402_1005Metric_Pad0.72x0.64mm_HandSolder | R1, R2 |
| 2 | 100 | Resistor_SMD:R_0402_1005Metric | R9, R11 |
| 2 | 100 nF | Capacitor_SMD:C_0402_1005Metric_Pad0.74x0.62mm_HandSolder | C3, C5 |
| 2 | 100nF | Capacitor_SMD:C_0402_1005Metric_Pad0.74x0.62mm_HandSolder | C2, C22 |
| 2 | 10k | Resistor_SMD:R_0402_1005Metric_Pad0.72x0.64mm_HandSolder | R7, R8 |
| 2 | 1N4148WT | Diode_SMD:D_SOD-523 | D1, D2 |
| 2 | 22u | Capacitor_SMD:C_0805_2012Metric | C17, C18 |
| 2 | 3.3pF | Capacitor_SMD:C_0402_1005Metric | C15, C16 |
| 2 | 3.9 nH | Inductor_SMD:L_0402_1005Metric_Pad0.77x0.64mm_HandSolder | L4, L5 |
| 2 | 47pF | Capacitor_SMD:C_0402_1005Metric | C10, C11 |
| 2 | 5k1 | Resistor_SMD:R_0402_1005Metric_Pad0.72x0.64mm_HandSolder | R5, R6 |
| 1 | 0900FM15K0039 | RF_Converter:Balun_Johanson_0900FM15K0039 | FL1 |
| 1 | 1.5pF | Capacitor_SMD:C_0402_1005Metric_Pad0.74x0.62mm_HandSolder | C20 |
| 1 | 10 uF | Capacitor_SMD:C_0402_1005Metric_Pad0.74x0.62mm_HandSolder | C4 |
| 1 | 100nF | Capacitor_SMD:C_0402_1005Metric | C8 |
| 1 | 10uF | Capacitor_SMD:C_0402_1005Metric_Pad0.74x0.62mm_HandSolder | C21 |
| 1 | 1575AT43A0040 | Private_Antenna:609-1575AT43A0040E | AE1 |
| 1 | 15uH | Inductor_SMD:L_0402_1005Metric | L1 |
| 1 | 1M | Resistor_SMD:R_0402_1005Metric_Pad0.72x0.64mm_HandSolder | R4 |
| 1 | 1uF | Capacitor_SMD:C_0402_1005Metric_Pad0.74x0.62mm_HandSolder | C1 |
| 1 | 1uF | Capacitor_SMD:C_0402_1005Metric | C19 |
| 1 | 220 | Resistor_SMD:R_0402_1005Metric_Pad0.72x0.64mm_HandSolder | R3 |
| 1 | 300 | Resistor_SMD:R_0402_1005Metric | R10 |
| 1 | 39pF | Capacitor_SMD:C_0402_1005Metric | C14 |
| 1 | 4.7 nF | Capacitor_SMD:C_0402_1005Metric_Pad0.74x0.62mm_HandSolder | C6 |
| 1 | 470nF | Capacitor_SMD:C_0402_1005Metric | C9 |
| 1 | 47nH | Inductor_SMD:L_0402_1005Metric | L2 |
| 1 | 9.1nH | Inductor_SMD:L_0402_1005Metric | L3 |
| 1 | AMS1117-3.3 | Package_TO_SOT_SMD:SOT-223-3_TabPin2 | U5 |
| 1 | ATGM336H | Private_GPS:ATGM336H | U7 |
| 1 | ATSAMD21G18A-A | Package_QFP:TQFP-48_7x7mm_P0.5mm | U2 |
| 1 | BME280 | Package_LGA:Bosch_LGA-8_2.5x2.5mm_P0.65mm_ClockwisePinNumbering | U6 |
| 1 | Conn_Coaxial | Custom_SMA_Connector:RFSOLUTIONS_CON-SMA-EDGE-S | Je2 |
| 1 | ECS-327TXO-2012 | Custom_Oscillator:OSC_ECS-327TXO-2012-33-TR | U3 |
| 1 | FA-128_32.0000MF20X-K5 | Custom_Oscillator:OSCCC200X160X50 | Y1 |
| 1 | LED | LED_SMD:LED_0402_1005Metric | D3 |
| 1 | PE4259 | RF_Switch:PE4259 | U1 |
| 1 | POWER IN | Connector_PinHeader_2.54mm:PinHeader_1x02_P2.54mm_Vertical | J2 |
| 1 | RST | Button_Switch_SMD:SW_Tactile_SPST_NO_Straight_CK_PTS636Sx25SMTRLFS | SW1 |
| 1 | SX1262IMLTRT | Package_DFN_QFN:QFN-24-1EP_4x4mm_P0.5mm_EP2.6x2.6mm | U4 |
| 1 | USBC | Connector_USB:USB_C_Receptacle_GCT_USB4105-xx-A_16P_TopMnt_Horizontal | J1 |
| 1 | ~ | Connector_PinHeader_2.54mm:PinHeader_1x05_P2.54mm_Vertical | J3 |
Questions
How big is the Topaz PCB?
It measures 30.5 × 72.9 mm and has 4 copper layers, 1.22 mm thick.
What parts does the Topaz use?
60 parts, built around the ATSAMD21G18A-AU, PE4259-63, SX1262IMLTRT and BME280. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the Topaz KiCad files?
From the dfedor2008/Topaz repository on GitHub, at the commit this page was made from: the board is Topaz.kicad_pcb and its schematic Topaz.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Topaz design in my own project?
Its repository states no licence, so its author keeps all rights: ask dfedor2008 before reusing the design.
Similar boards
- 2 layers68.3 × 94.8 mm
- 4 layers40 × 40 mm
- 4 layers40 × 40 mm
Pq obc comms
abelwu2001/Picosat-Pocketcube-UTN-FRC-2026
Proyecto Final para el armado de un nanoSat
68 parts3 - 4 layers35.1 × 76.3 mm
Tiny4FSK
New-England-Weather-Balloon-Society/Tiny4FSK
Horus Binary v2 HAB Tracker
90 parts96CERN-OHL-W-2.0 - 4 layers18 × 63 mm
- 4 layers61.8 × 79.6 mm
- 4 layers40.5 × 80.2 mm
NULL
jadenvv/NULL
A version of a flipperzero that has the same capabilities of Sub-GHz RF, IR, Wifi, and NFC/RFID
121 parts1