Don Park

• frame
  • 3D printed motor mounts, frame core
  • arms: 3d printed or carbon fiber
  • 230mm ($22) http://www.hobbyking.com/hobbyking/store/__61390__Laser230_FPV_Quadcopter_Composite_Kit_230mm_.html
• Flight Controller
  • Teensy LC primary processor ($11)
    • http://www.pjrc.com/teensy/teensyLC.html
  • KK-Mini http://multirotorpilotmag.com/hobby-king-kk-mini-multi-rotor-flight-control-board-36x36mm/ ($25 w/ MPU)
  • OpenPilot CC3D ($14) http://www.banggood.com/OpenPilot-CC3D-Flight-Controller-STM32-32-bit-Flexiport-p-937044.html
• motors
  • 7mm generic ($21 for 4, ebay)
  • brushless ZMR1804 ($9/ea, $36)
    • http://www.banggood.com/ZMR-1804-2400KV-Micro-Size-Integration-Outrunner-Brushless-Motor-p-923424.html
    • https://www.youtube.com/watch?v=9emHiQ4as4w
  • RCX 1804 w/ ESC ($14) http://www.banggood.com/SimonK-10A-ESCRCX-1804-2400KV-Motor-Gemfan-5030-Propeller-For-QAV250-p-937534.html
• Accelerometer board
  • MPU-6050 ($2)
  • http://www.banggood.com/Electronic-Compass-Module-Three-Axis-Magneto-Resistive-Sensor-p-926151.html
• Wifi board ESP8266 ($3)
• Sonar board ($3)
  • http://www.ebay.com/itm/HC-SR04-Scheda-Sensore-Ultrasuoni-Sonar-Sensori-di-Distanza-Arduino-/261576743635

Total: $

An OSHPark pcboard using through-hole tech to be heart of the copter.

Power lines

• Lipo
• Teensy LC
• ESP8266
• MPU 6050
• Speed controller(x4)

Data

• Teensy - MPU6050 = I2C
• Teensy - ESP8266 = Serial
• Teensy - ESC = AnalogOut

Circuit layout app: ?