Callers' Approach Alarm
Alarm Rings When Caller Approaches
This alarm rings so that callers approaching the door may be seen before they ring the bell and one can exercise his pleasure about admitting them.
If one has a wooden walk, the alarm is easy to fix up. Take up about 5 ft. of the walk and nail it together so as to make a trapdoor that will work easily. Place a small spring under one end to hold it up about 1/4 in. (A, Fig. 2). Nail a strip of tin along the under side of the trap near the spring and fasten another strip on the baseboard, so that they will not touch, save when a weight is on the trap. Connect up an electric bell, putting the batteries and bell anywhere desired, and using rubber-covered wire outside the house, and the alarm is complete.
When a person approaching the house steps on the trap, the bell will ring and those in the house can see who it is before the door bell rings.
Contributed by R. S. Jackson, Minneapolis, Minn.