EmbeddedRelated.com
The 2026 Embedded Online Conference
    Parts    Project Advisor    Project Ideas    USB-C RF Receiver for Wireless Temperature/Humidity Sensors

USB-C RF Receiver for Wireless Temperature/Humidity Sensors

A USB-C plug-in receiver that listens for inexpensive wireless remote temperature and humidity sensor transmissions and forwards the readings to a PC.

Intermediate Project — This is an intermediate project because it combines USB device firmware with sub-1 GHz RF reception and likely protocol decoding, which requires careful RF layout, timing capture, and host-side data handling.
Assumptions:
  • The remote sensors are common low-cost sub-1 GHz devices, likely using simple OOK/FSK or a proprietary protocol rather than WiFi/BLE.
  • The device is a prototype dongle that will enumerate as a USB serial device or similar on the PC, so no separate display or storage is required.
  • The user wants a practical build using readily available parts from major distributors, not a custom RF front end from scratch.

Bill of Materials

Microcontroller
Top Pick ESP32-S3-DEVKITC-1 Espressif Systems From our database
ESP32-S3-DEVKITC-1 is the best overall prototype MCU because it gives you native USB, strong processing headroom, and a very practical development experience for decoding RF sensor packets and streaming them to the PC.
STM32F072CBT6 STMicroelectronics From our database
Crystal-less USB 2.0 full-speed MCU with enough performance for packet parsing and USB CDC/serial output. It is a solid low-cost choice if you want a simple wired USB dongle architecture and do not need wireless connectivity on the MCU itself.
Raspberry Pi Pico Raspberry Pi From our database
Very accessible prototype platform with native USB and strong community support. The RP2040 has enough GPIO and timing flexibility for SPI-controlled RF transceivers and is easy to program for a first-pass receiver.
RF Transceiver
Top Pick CC1125 Texas Instruments From our database
Top pick: CC1125 (Texas Instruments). Higher-performance sub-1 GHz transceiver with very good sensitivity and narrowband capability, useful if the sensors are weak or the environment is noisy. It is more capable than a basic receiver but also more complex to bring up.
SX1276MB1LAS Semtech From our database
LoRa-capable sub-1 GHz module with an SMA connector, useful if the sensors are known to use LoRa-like modulation or if you want a ready-made RF module. It is less ideal than CC1101 for generic cheap remote sensors, but it is easy to prototype with.
Power Supply
Top Pick STUSB4500QTR STMicroelectronics From our database
Top pick: STUSB4500QTR (STMicroelectronics). Useful if you want the dongle to negotiate USB-C power explicitly instead of relying on default 5 V behavior. It is more relevant for a custom powered accessory than for a simple low-power receiver, but it can be part of a more polished USB-C design.
USB-C powered from the PC System-level choice AI suggestion - verify availability
For a prototype dongle, the simplest and most reliable power source is the PC's USB-C port itself. This avoids battery charging complexity and keeps the build compact, while the MCU dev board can provide the needed 3.3 V rail for the RF module.
MCP73871-4CAI/ML Microchip Technology From our database
Good battery-charge and power-path IC if you decide the receiver should also run from a Li-Ion cell. It is not necessary for a PC-powered prototype, but it is a practical option if you later want portable operation.
Connectivity
Top Pick STM32F072CBT6 STMicroelectronics From our database
No separate connectivity chip is really needed if you use STM32F072CBT6 or an MCU with native USB, so the best practical path is to let the MCU handle USB directly rather than adding extra interface silicon.
Dev Board NUCLEO-F031K6 STMicroelectronics
Ready-to-use board for prototyping with this chip
CH340C WCH
Low-cost USB-to-UART bridge if you prefer a very simple serial-output architecture from the MCU. It is widely used in prototypes, though native USB on the MCU is usually cleaner for this project.
CYPD3120-40LQXI Infineon (Cypress) From our database
Highly integrated USB-C controller with PD support if you want a more advanced USB-C accessory design. It is overkill for a basic receiver dongle, but it can simplify Type-C port handling in a custom product.

Compatibility Notes

  • The ESP32-S3-DEVKITC-1 is a 3.3 V SPI device, so it pairs naturally with 3.3 V MCUs like ESP32-S3-DEVKITC-1 or STM32F072CBT6.
  • If you use a dev board powered from USB-C, confirm it exposes a stable 3.3 V rail with enough current for the RF module and any external antenna front end.
  • The RF module and MCU should share a common ground and short SPI traces; RF performance will suffer if the module is placed too close to the USB connector or noisy switching regulators.
  • If the target sensors use 433 MHz or 868/915 MHz, the antenna and regional band choice must match the sensor protocol.

You'll Also Need

  • A suitable antenna for the chosen sub-1 GHz band.
  • USB-C cable and enclosure.
  • Level shifting only if you choose a 5 V-only board, which is not recommended here.
  • Firmware to decode the specific sensor protocol and format the data for the PC.
  • Optional RF front-end passives such as matching network components, decoupling capacitors, and ESD protection.
Estimated BOM Cost: $15-35 (based on live distributor pricing)

Design Considerations

Protocol Uncertainty
The biggest risk is that the inexpensive sensors may use a proprietary OOK/FSK protocol rather than a standard one. Start with a flexible receiver like ESP32-S3-DEVKITC-1 and capture raw timing first, then decode the packet format in firmware. If the sensors turn out to be 433 MHz fixed-format devices, you can often get a working prototype quickly without needing a full protocol stack.
USB-C Simplicity
For a prototype, do not overcomplicate the USB-C side unless you need more than default 5 V power. A USB-powered MCU board is usually enough, and it avoids USB-PD negotiation bugs that can delay bring-up. If you later move to a custom PCB, then a controller like STUSB4500QTR becomes more relevant.
RF Layout and Antenna
ESP32-S3-DEVKITC-1 GHz reception is very sensitive to antenna placement and ground return quality. Keep the antenna away from the USB connector, MCU clock traces, and any switching regulators, and use the antenna recommended for the sensor band. Even a good receiver IC will perform poorly if the antenna is detuned by the enclosure or nearby copper.
Firmware Architecture
Use an interrupt-driven or DMA-assisted SPI receive path and a small state machine for packet capture, validation, and USB reporting. Add a watchdog and a timeout-based resync path because cheap remotes often transmit infrequently and with variable preambles. Logging raw RSSI and packet timing during development will make protocol reverse engineering much easier.
Power and Noise
USB bus power is convenient, but the PC's 5 V rail can be noisy. Use local decoupling near the RF module and keep the 3.3 V rail clean, especially if the dev board uses a switching regulator. If you see missed packets, check for supply ripple and ground bounce before assuming the RF protocol is the issue.
Validation Strategy
Test first with the sensor very close to the antenna, then move it through walls and at increasing distance to characterize link margin. Record raw captures from multiple sensor transmissions to confirm whether the device sends repeated frames, rolling IDs, or checksum fields. This will tell you whether the receiver is robust enough for real-world use or only works in ideal lab conditions.

Want to customize this project or build something different?

Try the Project Advisor
The 2026 Embedded Online Conference