Wellness Device Prototype Assembly

I need 5 working hardware prototypes assembled and tested. This is a personal wellness/fitness device that measures breath flow rate via a pressure sensor and sends the reading to a phone over Bluetooth. This is NOT a medical device — no diagnostic claims, no clinical features. It's a simple breath-flow fitness tracker, similar in spirit to a fitness wearable.

Components (already specified)


1x ESP32 dev board (any standard ESP32 dev board with an ADC-capable GPIO pin, e.g. ESP32-WROOM-32 dev kit)
1x MPXV7002DP differential pressure sensor (NXP/STMicroelectronics, ±2kPa)
1x LiPo battery (150–500mAh) with a basic charge/protection module
A short length of tubing and a 3D-printed or off-the-shelf disposable mouthpiece adapter to connect the airway to one pressure port on the sensor
Basic wiring (jumper wires or soldered point-to-point — no custom PCB needed for this stage)
A simple enclosure (3D-printed box is fine, doesn't need to be polished — functional only)


What "done" looks like

Each of the 5 units should:


Power on from the LiPo battery
Read the MPXV7002DP sensor via the ESP32's analog input
Stream raw voltage/pressure readings over Bluetooth Low Energy (BLE) — a simple GATT characteristic broadcasting numeric values is sufficient, no need for a polished app yet
Be testable with a generic BLE scanner app (e.g. "nRF Connect" on phone) so I can confirm readings change when I blow into the mouthpiece
Be housed in a basic enclosure so it's safe and convenient to handle (doesn't need to look good, just hold together and not have exposed wiring near the mouth)


What I'll provide


This brief and any clarifying answers
Budget for components (to be purchased on my behalf and itemised, or I can pre-order and ship to you — happy to discuss)
Reasonable turnaround flexibility — this is a personal R&D project, not a tight deadline


What I'm NOT asking for at this stage


No custom PCB design
No polished app — basic BLE broadcast/readable values is enough
No clinical calibration against a reference spirometer (I'll handle validation separately)
No enclosure design/manufacturing polish


Ideal background


Experience with ESP32/Arduino-style microcontroller projects
Comfortable with basic analog sensor wiring and BLE GATT basics
Bonus: experience with simple 3D-printed enclosures (or willingness to use a basic existing enclosure design)


Deliverables


5 assembled, working units
Brief documentation: wiring summary, any firmware code used (open and editable, not locked), and notes on how to read the BLE output
A short demo (video or live call) showing each unit responding to airflow