How to Make a Low Cost Smoke Detector

By: Carmen Chan, Nicholas Yiu, Professor David Levine

Almost half the world cooks on inefficient wood and charcoal cook stoves. These stoves kill over a million people and especially young children annually from indoor air pollution. Improved cook stoves exist, but it is very expensive to monitor how much they reduce particulate emissions in the field. The objective of this project was to design a protocol and test low-cost particulate detectors based on tape, white paper, Dixie cups and citric acid. We wanted to simulate a cookstove, like ones in Uganda, so we loosely wrapped the steel drum with foil, so keep the smoke contained. A handful of careful tests may show if these low-cost methods hold promise.

SMOKY FIRE PROTOCOL

The following are a list of rules and regulations that should always be followed when lighting a fire. Failure to do so may result in harmful consequences.

1. Always start a fire in a container (the 55-gallon steel barrel or a barbeque pit)
2. Always have at least three to four damp towels with you to prevent fire spreads
3. Always have a fire extinguisher to control fire in case of unexpected fires
4. Make sure the area around the fire area is not too dry and clear area of any flammable materials
5. (optional) Wear face masks to prevent inhalation of smoke particulates
6. Use barbeque tools to keep fingers and hands from the fire

STARTING A FIRE

1. Spray the coals evenly all over with charcoal lighter fluid until they are saturated
2. Close the lighter fluid container tightly, and set the container away from the grill
3. Using a long match or long-handled butane lighter, light the fluid-saturated briquettes in several spots, watching to see that the flames leap to other charcoal until the entire stack is burning

MATERIALS:
Dixie cups
Clear Tape
Paper (preferably smooth)
Citric acid (in the form of lemon juice)
Steel drum
Fire starting materials (coal, lighter, fuel)
Foil

PROCEDURE:
1) cut a square piece of paper
2) wrap the paper around the dixie cup (as shown in Picture)
3) secure with tape
4) evenly distribute citric acid on paper
5) tape along edge of steel drum upsidedown! (as shown in Picture)
6) start fire
7) wrap steel drum loosely with foil
8) check paper for signs of particle and color change

Ideally, the smoke would not escape as much due to the foil containing the smoke within the steel drum. Any particles and particulates from the smoke would be caught in the paper. The heat would show color change on the paper due to oxidation of the citric acid.