Contact person: Business Client

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Location: Delhi, India

Budget: Recommended by industry experts

Time to start: As soon as possible

Project description:
"I am seeking a skilled freelance electronic engineer to develop a bench-tested, functional prototype of a simulator type biomedical device. This is a low-cost, reusable physical training device that accurately simulates the Sentinel Lymph Node Biopsy (SLNB) procedure using safe, non-radioactive infrared (IR) technology.

Need people equipped to perform the following duties:
Hardware:
Component Selection & Sourcing: Ensuring component compatibility (e.g., IR LED wavelength and phototransistor sensitivity).
Schematic Capture: Design the complete circuit for the handheld probe, including:

ESP32-WROOM-32 Dev Board as the core.
IR Phototransistor (e.g., L-53P3CT) with appropriate biasing and signal conditioning circuit.
Piezo buzzer driver circuit.
0.96" I2C OLED Display (SSD1306) connections.
Power management from a USB power bank (e.g., 5V to 3.3V LDO if necessary).
Headers/ports for programming and debugging.

PCB Layout & Assembly:
Design a compact, single-sided or double-sided PCB that fits ergonomically within a 3D-printed probe enclosure (I will handle the mechanical enclosure design).
Generate all necessary Gerber and assembly files.
Procure and assemble one working PCB.

Firmware:
Embedded C (PlatformIO/Arduino Framework):
Read the analog RSSI from the phototransistor via the ESP32's ADC at a high sampling rate.
Implement software filtering (e.g., moving average, low-pass filter) to smooth the raw ADC data.
Map the filtered signal to a "Counts Per Second" (CPS) value.
Drive the audio feedback: control the piezo buzzer to emit beeps with a frequency proportional to the CPS.
Drive the visual feedback: update the OLED display in real-time with a numerical CPS value and a corresponding bar graph.
Manage the I2C communication with the OLED display.
Implement the control sequence for the external IR LEDs if they are to be pulsed or multiplexed.

Python (Runs on a connected PC for data analysis):
Develop a lightweight script that can communicate with the ESP32 via its serial port (USB).
On command, the script will request a data dump from the ESP32.
The script will format this data into a timestamped CSV report file.

Deliverables
Complete Design Package:
Schematic (PDF and native format, e.g., KiCad/Altium).
PCB Layout Files and Gerbers ready for fabrication.

Functional Prototype:
One fully assembled, programmed, and tested handheld probe PCB. A set of external IR LEDs (on breadboard/perfboard) for testing.

Software & Documentation:
Well-commented, structured Embedded C source code for the ESP32. Lightweight Python script for CSV report generation. Build and flashing instructions for the firmware. Instructions for using the Python data export tool." (client-provided description)