5c. Put all the LEDs on the same side so you can see them
through the plastic case. Put tape around each transistor to
make sure they don’t touch. Install the 555 and 4017 chips after
all soldering is complete.
5d. Check your wiring, then power up the circuit. If the oscillator
LED doesn’t flash, turn off the power and check your circuit.
5e. For testing, install 2 flashlight bulbs in place of the igniters.
Make sure they fire in sequence.
5f. Drill 2 holes in the plastic container for the switches and
1 hole for the igniter wires. Cut the lower stage ignition wires
4" long and solder alligator clips to the end. Cut the upper stage
ignition wires 2" long and solder alligator clips to the ends. Seal
the igniter wire hole with silicone.
5g. Stuff the electronics, battery, and a piece of foam padding
into the case.
5h. Glue the electronics case onto the top of the first stage. This
is where you’ll clip the electronics to the igniters before launch.
6. GENERATE THE GAS
Two people are required when making the gas; one with dry hands controlling the power supply, the other
handling the rocket in the water.
CAUTION: This step involves a shock hazard. Responsible adult supervision is required. !
6a. Put the gas generator assembly in the bottom of the 5gal
bucket, with the wires running outside the bucket.
6b. Fill the gas generator bucket with warm water so the top of
the funnel is completely covered (about 5 gallons). Mix in baking
soda based on the current capacity of your battery charger; 40
grams for 10 amps, 80g for 20A, 120g for 30A, and 160g for 40A.
6c. Attach the wires to the battery charger and plug in the
charger. You should see bubbles coming out of the funnel.
SAFETY WARNING: Never put your hands in the water when the battery charger is plugged into the wall!
Even if the charger is off, you could get electrocuted. The gas mixture you are generating is explosive;
operate in a well-ventilated place (outside is ideal) away from any flame or source of ignition. Wear safety
goggles, and again, keep the power supply unplugged when anyone’s hands are put into the water.