TM 31-210
Improvised Munitions Handbook
| Section VI |
No. 6 |
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DRIED SEED TIMER |
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| A time delay device for electrical firing circuits can be made using the principle of expansion of dried seeds. | |
| MATERIALS REQUIRED: | |
| Dried peas, beans or other dehydrated seeds |
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| Wide mouth glass jar with non-metal cap | |
| Two screws or bolts | |
| Thin metal plate | |
| Hand drill | |
| Screwdriver | |
| PROCEDURE: | |
| 1. Determine the rate of rise of the dried
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. b. Measure the time it takes for the seeds to rise a given height. Most dried seeds increase 50% in one to two hours. |
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2. Cut a disc from thin metal plate. Disc should fit loosely inside the jar. |
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| NOTE: If metal is painted, rusty or otherwise coated, it must be scraped or sanded to obtain a clean metal surface. |
| 3. Drill two holes in the cap of the jar about 2 inches apart. diameter of holes should be such that screws or bolts will thread tightly into them. If the jar has a metal cap or no cap, a piece of wood or plastic (NOT METAL) can be used as a cover. |
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| 4. turn the two screws or bolts through the holes in the cap. bolts should extend about one in. (1 1/2 cm) into the jar. |
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| IMPORTANT: Both bolds must extend the same distance below the container cover. |
| 5. pour dried seeds into the container. The level will depend upon the previously measured rise time and the desired delay. | |
| 6. Place the metal disc in the jar on top of the seeds. |
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| HOW TO USE: | |
| 1. Add just enough water to completely cover
the seeds and place the cap on the jar.
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| 2. Attach connecting wires from the firing circuit to the screws on the cap. |
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| Expansion of the seeds will raise the metal disc until it contacts the screws and closes the circuit. | |
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