ESP32-S3 IoT Mini Controller Assembly, Firmware Flashing & 24V Bench Testing – 5 Pilot Units
Budget: $30 – $250 USD
We are looking for an experienced electronics / embedded hardware freelancer to help assemble and test 5 pilot units of an ESP32-S3 based IoT mini controller.
The PCB/PCBA boards are already designed and manufactured by JLCPCB. The firmware file is also ready. This project is not for PCB design and not for firmware development from scratch. The main task is physical assembly, firmware flashing via USB-TTL, and basic bench testing.
The final goal is to prepare 5 working pilot units in the correct order:
Milestone 1:
Assemble, flash and test 1 pilot unit first.
Milestone 2:
After the first unit is validated successfully, assemble, flash and test the remaining 4 units using the same process.
Scope of work:
* Mount the PCB/PCBA into an IP65/IP66 enclosure
* Connect the external U.FL Wi-Fi antenna
* Prepare simple 24V DC input wiring
* Prepare output wiring for Relay / PhotoMOS / Open Collector
* Flash the firmware via USB-TTL
* Perform a basic 24V DC power-on test
* Test the outputs with a multimeter
* Confirm that the device powers on correctly
* Send clear photos and a short video proof of the working unit
* Repeat the same process for the remaining 4 units after the first unit is approved
Important technical notes:
* The controller uses ESP32-S3-WROOM-1U with external U.FL antenna
* The outputs are dry-contact / signal-level outputs, not load drivers for motors or pumps
* No PCB redesign is required
* No GPIO remapping is required
* No firmware logic changes are required unless a flashing issue is discovered and discussed first
Preferred experience:
* ESP32 / ESP32-S3 hardware
* USB-TTL firmware flashing
* 24V DC electronics
* Basic enclosure assembly
* Multimeter testing
* Relay / dry contact / open collector outputs
* Clean wiring and small prototype assembly
We can provide:
* 5 JLCPCB PCBA boards
* Final firmware file
* Schematic PDF
* PCB photos
* GPIO mapping
* BOM / Gerber / JLCPCB production package if needed
* Main components that remain inside the controller, such as enclosure, U.FL antenna, cable glands, wires, ferrules and PCB spacers
The freelancer should preferably already have basic lab tools such as:
* USB-TTL 3.3V adapter
* 24V DC bench/test power supply
* Multimeter
* Basic soldering/wiring tools
* Heat-shrink tubing, labels, screws or small local consumables
Please mention in your proposal:
1. Your experience with ESP32 / ESP32-S3 devices
2. Your experience with USB-TTL flashing
3. Your experience with 24V DC testing
4. Whether you already have a 24V test power supply, USB-TTL adapter and multimeter
5. Your estimated price for Milestone 1: first pilot unit
6. Your estimated price for Milestone 2: remaining 4 units
7. Your estimated timeline after receiving the parts
Expected timeline:
* First pilot unit: 3–5 days after receiving the parts
* Remaining 4 units: 7–10 days after approval of the first unit
Detailed files will be shared only with the selected freelancer.
The PCB/PCBA boards are already designed and manufactured by JLCPCB. The firmware file is also ready. This project is not for PCB design and not for firmware development from scratch. The main task is physical assembly, firmware flashing via USB-TTL, and basic bench testing.
The final goal is to prepare 5 working pilot units in the correct order:
Milestone 1:
Assemble, flash and test 1 pilot unit first.
Milestone 2:
After the first unit is validated successfully, assemble, flash and test the remaining 4 units using the same process.
Scope of work:
* Mount the PCB/PCBA into an IP65/IP66 enclosure
* Connect the external U.FL Wi-Fi antenna
* Prepare simple 24V DC input wiring
* Prepare output wiring for Relay / PhotoMOS / Open Collector
* Flash the firmware via USB-TTL
* Perform a basic 24V DC power-on test
* Test the outputs with a multimeter
* Confirm that the device powers on correctly
* Send clear photos and a short video proof of the working unit
* Repeat the same process for the remaining 4 units after the first unit is approved
Important technical notes:
* The controller uses ESP32-S3-WROOM-1U with external U.FL antenna
* The outputs are dry-contact / signal-level outputs, not load drivers for motors or pumps
* No PCB redesign is required
* No GPIO remapping is required
* No firmware logic changes are required unless a flashing issue is discovered and discussed first
Preferred experience:
* ESP32 / ESP32-S3 hardware
* USB-TTL firmware flashing
* 24V DC electronics
* Basic enclosure assembly
* Multimeter testing
* Relay / dry contact / open collector outputs
* Clean wiring and small prototype assembly
We can provide:
* 5 JLCPCB PCBA boards
* Final firmware file
* Schematic PDF
* PCB photos
* GPIO mapping
* BOM / Gerber / JLCPCB production package if needed
* Main components that remain inside the controller, such as enclosure, U.FL antenna, cable glands, wires, ferrules and PCB spacers
The freelancer should preferably already have basic lab tools such as:
* USB-TTL 3.3V adapter
* 24V DC bench/test power supply
* Multimeter
* Basic soldering/wiring tools
* Heat-shrink tubing, labels, screws or small local consumables
Please mention in your proposal:
1. Your experience with ESP32 / ESP32-S3 devices
2. Your experience with USB-TTL flashing
3. Your experience with 24V DC testing
4. Whether you already have a 24V test power supply, USB-TTL adapter and multimeter
5. Your estimated price for Milestone 1: first pilot unit
6. Your estimated price for Milestone 2: remaining 4 units
7. Your estimated timeline after receiving the parts
Expected timeline:
* First pilot unit: 3–5 days after receiving the parts
* Remaining 4 units: 7–10 days after approval of the first unit
Detailed files will be shared only with the selected freelancer.