A time delay device for electrical firing circuits can be made using the principle of expansion of dried seeds.
Dried peas, beans or other dehydrated seeds
Expansion of the seeds will raise the metal disc until it contacts the screws and closes the circuit.
CONNECTING WIRES r—EXPLOSIVE
Wide mouth glass jar with non-
Two screws or bolts J ft U | TIM1
Thin metal plate
1. Determine the rate of rise of the ciriea seeds selected. This is necessary to determine delay time of the timer.
a. Place a sample of the dried seeds in the jar and cover with water.
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