Compact Battery-Powered Sensor Prototype
Budget: $1,500 – $3,000 USD
The goal of this short engagement is to turn my concept for a simple smart device into a working proof-of-concept. I need a tiny, battery-powered unit that senses when something is opened or closed, reports that state through a microcontroller (Arduino, ESP32, or similarly easy-to-program platform), and can run off a single coin cell for a reasonable period.
Scope of work
You’ll choose appropriate components, design the circuit, write minimal firmware, and assemble the prototype in a compact form factor rather than on a bulky breadboard. Off-the-shelf boards are fine so long as the final assembly is tidy and pocket-sized.
Key technical notes
• Sensor: open/close detection—magnetic reed switch or equivalent is acceptable.
• Power: coin cell battery with thoughtful power management (sleep modes, interrupt wake-up, etc.).
• Controller: any low-power 8-bit or 32-bit MCU you find suitable; I’m comfortable flashing code with Arduino IDE or PlatformIO.
• Enclosure is not required at this stage, but board layout and wiring should leave that option open.
Deliverables
1. Schematic and annotated parts list (including recommended coin cell holder).
2. Well-commented source code that compiles and runs, showing current state via serial output or a simple LED indicator.
3. Photos or short video of the assembled compact prototype demonstrating open vs. closed detection.
4. Brief power-consumption summary (sleep vs. active).
5. Shipment of the working prototype to my address, or guidance for me to reproduce it if remote shipping is impractical.
Acceptance criteria
• Prototype reliably distinguishes open and closed states at least 50 consecutive cycles.
• Idle current low enough to give an estimated several-month lifespan on a common CR2032.
• Firmware and documentation clear enough for a hobbyist to modify.
I’m ready to start as soon as you confirm component availability and a realistic timeline.
Scope of work
You’ll choose appropriate components, design the circuit, write minimal firmware, and assemble the prototype in a compact form factor rather than on a bulky breadboard. Off-the-shelf boards are fine so long as the final assembly is tidy and pocket-sized.
Key technical notes
• Sensor: open/close detection—magnetic reed switch or equivalent is acceptable.
• Power: coin cell battery with thoughtful power management (sleep modes, interrupt wake-up, etc.).
• Controller: any low-power 8-bit or 32-bit MCU you find suitable; I’m comfortable flashing code with Arduino IDE or PlatformIO.
• Enclosure is not required at this stage, but board layout and wiring should leave that option open.
Deliverables
1. Schematic and annotated parts list (including recommended coin cell holder).
2. Well-commented source code that compiles and runs, showing current state via serial output or a simple LED indicator.
3. Photos or short video of the assembled compact prototype demonstrating open vs. closed detection.
4. Brief power-consumption summary (sleep vs. active).
5. Shipment of the working prototype to my address, or guidance for me to reproduce it if remote shipping is impractical.
Acceptance criteria
• Prototype reliably distinguishes open and closed states at least 50 consecutive cycles.
• Idle current low enough to give an estimated several-month lifespan on a common CR2032.
• Firmware and documentation clear enough for a hobbyist to modify.
I’m ready to start as soon as you confirm component availability and a realistic timeline.