Alex Wanamaker

 2 astable 555 timer circuits  Blinking rate: ~1.1 seconds  Q1 and Q2 used to provide additional current for the circuit beyond the 555 timer’s limit of 200 mA  NXP SuperFlux LEDs: 110° viewing angle  LEDS require 70 mA min.  +3.3V supplied by GPIO P4  Interface with U1 through 6-pin Molex connector  PCB Layout of final product

 NXP LPC2378 ARM7 Microcontroller  32-Bit  512 kB flash  8 kB SRAM  104 GPIO ports  20 MHz crystal (X1)  Powered via +5V USB mini B connection (J3 and J4)  Produces +3.3V for ICs, GPIO, and external devices

 ETVS001 USB Port Protection (U2)  Provides protection for each line and between the supply voltage and ground for up to 25 A and 500 W within 8/20 μS.  NPC (U3)  18V max input, +3.3V output  Produces output current of 800 mA  USB mini B SMD connector (J4)

 Nickel-Metal Hydride High Capacity Battery Pack (B1)  9.6V, 2 Ah rechargeable battery pack with Tamiya connector J1  2-Pin Tamiya connectors (J1 and J2)  J2 interfaces with J1 to provide power to U4  Power can be turned on/off by the user using SWI1  LMZ14203 Switching Power Module (U4)  Takes 8 – 42V max, outputs +3.3V or 5V based on selection  5-Pin USB mini B connector (J3)  Provides +5V to U1 to power the whole system

 ADS7843 controller  12-bit ADC with synchronous serial interface  Typical power dissipation: 750 μW  Includes a shutdown mode, with power dissipation at ~ 0.5 μW  Can operate on 2.7V

 2.8”, 240x320 RGB resolution  TFT touchscreen interface  Includes backlight control

 Micro-SD (J5)  Surface mount Micro-SD Socket  Push in, Push out interface  Supports up to 4 GB storage  Interfaces with U1 to read from/write to an SD card  US1881 Hall Effect Device (U8)  Outputs 1 or 0 based on magnetic field  Used to calculate distance and speed

GPIO ports:  P4 (J7)  Interfaces with turn signal switches to display on- screen indicator  IO9 and IO11 detect switch voltage for left and right switches, respectively  IO10 and 12 output voltage to turn signal  P3 (J8)  Powers U8, counts pulses from U8 on IO1 for calculations

 12-pin Molex  Used to connect U1, U8, SW1, SW2, J7, and J8 with the turn signal via J6  Both J9 and J6 will be detachable from the bicycle  J10 and J11 will remain on the frame of the bicycle