P1: Nitrous at Balls in '08

Hybrid Launch Control

Last Update, 11/3/07 by Stephen Daniel

Break Out Box Design Notes

This page contains random notes we wanted to save on the design of the break-out box.

Notes on the Schematics

  • LED channel indicator
    • LSDiodes 5mm T1-3/4 Green
    • 3.3V 20mA nominal
  • Calculating the limiting resistor for the indicator diode:
    • 1N4148 @ 20mA has a 1.0V forward drop
    • 8V supply
    • MOSFET = IRF3709 has a negligible on-voltage drop
    • LED + diode have 4.3V forward drop
    • need 3.7V resistor drop
      R=V/I R = 3.7/0.020 = 185 Ohm
      Using actual 200 Ohm
  • Jumper wires are 12 gauge (These are used for a number of high-current internal connections on the PCB)
  • 16AWG wire for high-current connectors (Wires from the PCB to the high-current connectors.)

Cable and Connector Pinouts

  • Signal Cable Pinout
    The signal cable connector is designed for a 9-wire cable. We've wired it with a cat-5 cable (4 twisted pairs). We've left channel 5 unwired as a result.
    Pin Signal Color
    1 +8 V blue/w
    2 ch 0 blue
    3 ch 1 o/w
    4 ch 2 o
    5 ch 3 br/w
    6 ch 4 br
    7 ch 5 N/C
    8 ch 6 g/w
    9 gnd g
  • Solenoid Cable Pinout
    The solenoid cable is a simple two-wire power cable. The + wire is connected (through a fuse) to the positive supply voltage. The Vsw signal is switched by a power MOSFET to ground.
    Pin Signal
    1 V+
    2 Vsw
  • Power Cable Pinout
    The power cable is designed to conform to the solenoid cables. Thus solenoids can be tested by simply connecting the power cable to a solenoid cable, bypassing the break-out box.
    Pin Signal
    1 V+
    2 gnd