@South Hanau Intitute of Technology

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Technical Details

the startbox is designed for safe operation and fullfills the following requirements:

  • operation voltage: 6-12V (high capacity/current batteries only)
  • key switch
  • shortcircuit ignition line
  • check ignition circuit
  • test current <50mA
  • ignition line diameter >= 1.5mm²

Funktionsweise / How it works

  • after powering on and turning the key switch (arm switch in off position) the ignitor lines are short circuited to create a potential free environment and prevent misfire due to electrostatic charges.
  • if the arm switch is moved to up position a test circuit is activated and sends a small current through the ignition line
    • the test current is limited to ~ <50mA in total using a ultralow current led and a low current piezo buzzer to ensure a maximum test current of < 50mA
    • the yellow led right above the arm switch indicates the box is armed.
    • the red circuit test led is placed above the start button and should light up if the circuit is ready for operation and ignitor is connected properly. also the buzzer is start beeping.
  • if start button is pressed the ignitor will be fired using all current available limited by the fuse.
  • after successful ignition the start led and buzzer go off.

Circuit / Schaltung

Schaltplan / Schematics


Stromlauf (animiert)

Schaktkreis, Stromlauf, animiert

Power On

Stromlauf "Power On"

Power On, Key On, SAFE

Stromlauf "Arm Switch in 'safe' position"

Power On, Key On, ARMED

Stromlauf "Arm Switch in 'armed' position"

Power On, Key On, START

Stromlauf "Start Button pressed"

Power On, Key On, AFTER

Stromlauf "after ignitor fired"


designed by kalle/raketenclub
produced by liteon
limited to 35pcs (v1r0 2015)

PCB top
PCB bottom


component to pcb connections

arm switch / sicherungsschalter

arm switch, 9-polig SWA
SWA = Arm Switch / Sicherheits-Schalter

Pin Layout, Top view:
ON / OUT1 1 4 7
IN 2 5 8
ON / OUT2 3 6 9

PinNamecolor connects to the PCB on:
1SWA1black………. P21
3 not connected
7 not connected


Panel LED layout

Component Name Color colored cable connects to the PCB on: black cable connects to the PCB on:
Power LED LP red ….. P5 LP+ P19 LP-
Key Switch LED LK red ….. P10 LK+ P20 LK-
Arm LED (safe position) LSA green ….. P13 LSA+ P29 LSA-
Arm LED (armed position) LAR yellow ….. P12 LAR+ P31 LAR-
Start LED LST red ….. P14 LST+ P38 LST-

power switch


connects to PCB on:
Power Switch SWP P3 + P4

schluesselschalter / key switch


connects to PCB on:
Key Switch SWK P8 + P9

start taster/button


connects to PCB on:
Start Button SWZ P18 + P36

batterie anschlusskabel / battery cable

connects to PCB on:
BAT BAT+ (….. red wire) BAT +
BAT BAT- (….. black wire) BAT -

Sicherung / Fuse


2,5A, keramik, träge

connects to PCB on:
Fuse F P1 + P2



6-12V piezo buzzer

connects to PCB on:
Buzzer BUZ+ (….. red wire) P11
Buzzer BUZ- (….. black wire) P37

zuender buchsen / ignitor line sockets


connects to PCB on:
OUT Z+ (….. red wire) P35
OUT Z- (….. blue wire) P28

rc/prj/startbox/v1.0/10_tech/start.txt · Last modified: 2020/09/09 14:07 by kalle