Hardware/Firmware Engineer – Pressure-Sensing Voice Alarm Prototype

Job Title Hardware/Firmware Engineer – Pressure-Sensing Voice Alarm Prototype Project Description I am a registered nurse with a medical device concept to prevent patient falls in hospitals, long-term care facilities, and private homes. Current chair/bed alarms emit a generic beep that alerts staff (or a family caregiver) but means nothing to the patient. By the time someone arrives, the patient is often already on the floor. In a private home, the family caregiver may be in another room and can't get there in time. The Solution: A standalone device that detects when a patient or elderly loved one begins to stand and instantly plays a calm, personalized voice message saying "[Name], sit back down." This mimics what staff or family members would say—but delivers it instantly at the moment of movement. I need a working breadboard prototype to demonstrate the concept. What I Need Built A functional prototype with the following components: Sensor System: ● 4-point load cell array (placed under a chair cushion or rigid board) ● Detects weight distribution, not just total weight Detection Logic (firmware): ● Read all 4 load cells simultaneously ● Calculate Center of Pressure (CoP) ● Monitor rate of weight change ● Trigger ONLY when ALL THREE conditions are met: 1. Total weight greater than 20 lbs. (prevents empty chair triggers) 2. Rate of weight loss less than 30% per second (distinguishes standing from slow shifting) 3. Center of Pressure shifts forward 25% (distinguishes standing from reaching sideways) Audio Playback: ● DFPlayer Mini (or similar) audio module ● Small speaker with adjustable volume ● Physical "Record" button to record a 5–10 second voice message ● Physical "Reset" button to clear the recording Power: ● Battery-operated (rechargeable or replaceable) NOT Required: ● No Wi-Fi ● No Bluetooth ● No mobile app ● No smart features Target Users ● Hospitals (med-surg, orthopedics, ICU, geriatric units) ● Long-term care facilities (nursing homes, assisted living) ● Private homes (family caregivers managing elderly parents or spouses with dementia) What This Is NOT ● NOT a mobile app ● NOT a smart device ● NOT a wearable ● NOT a camera or motion sensor Deliverables 1. A working breadboard prototype with all components wired and functional 2. Arduino or compatible firmware code 3. Brief documentation explaining how it works 4. Demonstration video or live demo Budget Open to fixed-price or hourly. Prefer hourly $15 to $30. Location Preference US-based freelancers preferred. Questions for Applicants Please answer these in your proposal: 1. Have you designed hardware with load cells or pressure sensors before? 2. Do you have experience with medical devices or sensor-heavy products? 3. Based on this project, what microcontroller would you recommend and why? 4. Can you handle both hardware design AND firmware development? 5. Are you willing to sign a Non-Disclosure Agreement (NDA)? To Apply Please share examples of similar hardware projects you've built. Links to portfolios, photos, or videos are helpful. Timeline I'd like to have a working prototype within 4–6 weeks of starting. About Me I am a registered nurse with clinical experience in fall prevention across hospital and long-term care settings. I have tested this concept informally with a family member in a private home and confirmed that a calm voice command is more effective than a generic beep. This solution is designed for clinical facilities and private homes alike. I am now looking for an engineer to bring the hardware to life. Thank you for your interest. I look forward to reviewing your proposal.