Design a Printed Circuit Board

We are looking for a freelancer to design a carrier board for the Arduino MKR series microcontroller. This board will combine components found on the MKR Mem Shield, MKR IMU Shield, and MKR GPS Shield; these designs are open-source and available in Eagle for ready reference. Additional features to be added include a switching power supply, 0-20mA current loop input support, and test pads/external interconnects. Software is already developed, so pin-compatibility with existing shields is preferred. Design goals include: *** Integration of existing modules *** 1) Socket compatibility with the MKR WiFi 1010, MKR WAN 1310, and MKR GSM 1400 modules 2) Integration of the BNO055 IMU module from the MKR IMU 3) Integration of the SD card portion of the MKR Mem Shield (flash memory is not necessary) 4) Integration of the uBlox GPS from the MKR GPS Shield, including battery backup. NOTE: the MKR GPS requires external wiring that we want to incorporate into the mainboard *** Power Supplies *** 1) 24V/3A switching voltage regulator with input voltage range of 10-32V; voltage divider from V_in to maximum of 3V3 (to indicate V_in on AN5) 2) 5V switching regulator to power MKR board *** Sensor Inputs / Outputs *** 1) Integration of four 24V current loop 0-20mA sensor power supplies (with solder jumpers to enable/disable 24V supply) and 0-20mA-to-voltage converters (pins A1, A2, A3, A4) with calibration potentiometers and test pads (for example circuit, see: [login to view URL]) 2) A 0.1" test header with 24V, 5V, 3V3, A6 and GND (for an additional analog input) 3) One 5x1 pluggable terminal block for 24V, 5V, 3V3, D1, and GND (for a digital input with interrupt) 4) A row of 3x1 0.1" test headers with 3V3, GND, and all unused Digital pins broken out 5) Solder-holes for 24V, GND *** PCB layout / other considerations *** 1) 4 Corner Mounting holes 2) Silk-screen labeling test-points and header connections 3) Single-side / surface mount strongly preferred except header pins; large components are OK (e.g. 1210) Two-layer boards preferred; board size is not strictly constrained. This battery-operated board will be deployed in an industrial environment subject to vibration and temperature extremes. We anticipate paying three milestone payments as follows: 1) Upon sharing a complete schematic and a graphic of completed board layout 2) Upon sharing board design files (EAGLE preferred) and a complete bill of materials 3) Upon successful hardware validation (you can assemble the board, we can put one together, or we will have one made at OSHPark or CircuitHub)