Embedded Firmware Contractor

TruePutt LLC is building the GR-1 Pro™ (patents pending), a handheld electronic greens-reading device for golf. The device helps golfers read putts using computer vision, slope sensing, and audio guidance. We're hiring a contractor to build and validate the bench prototype. You'll own the platform end to end — build the breadboard, write the firmware, bring up the sensors, and sign off on the platform validation gates. Detailed technical scope is shared after NDA.

What you'll do

• Build the bench prototype on an 830-point breadboard from a specified BOM (already documented)
• Write and maintain the firmware in MicroPython on the OpenMV AE3 platform
• Bring up three time-of-flight sensors on a shared I²C bus, including address management at boot
• Implement a laser driver via a logic-level MOSFET with PWM, with safe-default behavior at boot and on fault
• Calibrate the onboard 6-axis IMU for slope accuracy
• Integrate audio, power, and button subsystems
• Integrate computer vision modules delivered by a second contractor into your firmware
• Execute and document the platform validation gates

What we're looking for

• 5+ years of embedded firmware experience with shipped projects you can speak to
• Production MicroPython or CircuitPython on a constrained MCU (Alif Ensemble, STM32, ESP32, RP2040, or similar)
• I²C at the protocol level: bus arbitration, address conflicts, pull-up sizing
• Practical analog: MOSFETs as low-side switches, PWM, pull-down sizing, dual-rail breadboard layouts
• Comfortable at a bench with multimeter and basic logic analyzer — this is not desk-only firmware work
• Laser-safety discipline (Class IIIb visible laser, OD-rated goggle protocol)
• Milwaukee metropolitan area out to Madison WI location is a must

Bonus Skills

• Prior OpenMV (AE3, H7, or earlier) experience
• Prior time-of-flight sensor experience, especially in multi-sensor arrays
• 6-axis IMU calibration experience
• LiPo + USB-C charging subsystem work

Engagement details

• 8–12 weeks, part-time (~10–15 hrs/week)
• Paired with a second contractor covering computer vision and algorithms; you're the Technical Lead
• Hourly rate discussed individually
• Strong potential to continue into a Phase 2 field prototype engagement (~12–16 additional weeks) if the fit is right
• NDA execution precedes detailed scope discussion