you can make a simple flash trigger from a scrap :) You just need 2 wires a cardboard and 2 pieces of alluminium foil. Check out this video and experiment.

From WebMDAllergies are an abnormal response of the immune system where the body’s defenses react to a usually harmless substance in the environment, such as pollen, animal dander, or food. Almost anything can trigger an allergic reaction, which can range from mild and annoying to sudden and life-threatening. Here are 10 of the most common triggers: Pollen -- Exposure to pollen from trees, grasses, and weeds can trigger hay fever or seasonal allergies. Symptoms include sneezing, runny nose, nasal congestion, and itchy, watery eyes. Treatments include over-the-counter