Electrical Engineer for Production-Ready LoRa Button & Receiver Ended

We are seeking an experienced Electrical Engineer to take our LoRa-based communication system from a functional prototype to a polished, production-ready design. If you have a strong background in developing field-proven, ultra-low-power LoRa devices, we want to hear from you.

WHAT WE'RE BUILDING

We are creating a highly reliable, *long-range encrypted button and receiver system*. The product is designed for secure, one-way communication over distances of 1.2 km or more. It needs to operate flawlessly in challenging urban and indoor environments where standard wireless solutions fail due to RF interference and obstructions.

At its core, the system consists of two parts:
1. A simple, battery-powered *Button (Transmitter)* that sends a secure signal when pressed.
2. A USB-powered *Receiver* that captures this signal and outputs the data to a connected device.

We are looking for an expert Electrical Engineer to help us turn our working prototype into a polished, manufacturable product.

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PROJECT OVERVIEW & CURRENT STATUS

We have already developed a basic prototype for a long-range, encrypted LoRa button and a matching receiver. Our progress so far includes:

• A functional core schematic.
• Initial firmware for the RAK3172 module.
• A rough 3D-printed enclosure concept.

Your mission is to refine this foundation into a robust and reliable product ready for pilot production. The primary challenge is achieving *secure communication over 1.2+ km* in dense urban environments with significant RF interference and physical obstructions.

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KEY TECHNICAL REQUIREMENTS

The final design must meet the following specifications:

• Core Component: The system will be based on the *RAKwireless RAK3172* module for both the button and receiver.
• Unified PCB Design: A critical requirement is to create a *single PCB layout* that can be selectively populated with components to function as either the button or the receiver, streamlining our manufacturing process.
• Button (Transmitter):
◦ Ultra-Low-Power: Must achieve a *3-5 year battery life* running on standard AA or AAA batteries. Power optimization is paramount.
◦ Firmware Updates: Must have a non-intrusive method for firmware updates (e.g., internal programming pads for pogo pins) without a visible external USB port.
• Receiver:
◦ Power & Data: The receiver will be powered via its USB port. It must output all received data to a host computer through a *USB-to-UART interface*.
• Security: The communication link must be secured with *AES-128 encryption* and incorporate rolling counters for robust replay attack protection.

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REQUIRED DELIVERABLES

Upon completion, you will provide a complete manufacturing package including:

1. Production-Ready PCB Files: Finalized schematic and layout files.
2. Manufacturing Data: Bill of Materials (BOM), Gerber files, and Pick-and-Place data for both device configurations.
3. 3D Model: A CAD/STEP file of the final PCB assembly.

We are looking to move quickly into pilot production and are eager to partner with a freelancer who can deliver a high-quality, field-ready design. read less