Could you tell me how to make some homemade spy gadgets?

Instructions

• Use lemon juice to send secret messages. Remember that the white paper is suspect, so writing something innocuous on standard ink. Professional spies suggest a shopping list.A noted makeup applicator can work well as a pen with lemon juice, but many household items will allow you to write legibly in invisible ink. This is one of the easiest gadgets homemade spy. Apply heat to read your message.
• Make dust for fingerprints spy kit. This spy gadget in the house will require adult help. Pour a small amount of cornstarch in a bowl of porcelain or china. Take a second plate and apply the flame of a candle with a long-handled lighter or candle. The soot builds up quickly. Scrape the soot into the cornstarch and stir. Keep adding until there is a soot-gray powder. Traces of dust with the dust and lift with tape.
• Make a periscope to see over fences and around corners. Cut a 2 inch square at one end of cardboard mailing tube with a knife. Make a diagonal cut 2 inches at each corner of the square. Repeat on the other end of the distribution pipe, the cut on the opposite side of the tube. Mount mirrors in 3 by 4 inch square of cardboard with glue and inserted into the slots in the tube. The mirrors are facing each other. Use tape to close the ends of the tube.
• At the same time a pair of swimming goggles Spy goggles normal. This spy gadget at home is all about appearance, but can be fun for children. Use a permanent marker to color the lens of his spy glasses. Avoid washable markers for this project.
• Add to the fun of spy gadgets home with a digital camera or inexpensive webcam hidden in a stuffed toy or other item. You might also consider passing along old mobile phones or Bluetooth headsets his spies little.