Fifty years ago this month, this young comrade was able to help feed his family by locating a school of fish. He managed this by seeking out the perfect water temperature, thanks to an electronic thermometer he constructed himself.

The plans for the project were contained in the April 1971 issue of Юный техник (Young Technician) magazine, which also contained the plans for making the raft, shown at left. It included a number of other circuits, including the one transistor regenerative radio receiver shown below.