CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($)	12 Months Ended
	Apr. 30, 2016	Apr. 30, 2015
CONSOLIDATED STATEMENTS OF OPERATIONS
Net sales	$ 16,194,000	$ 13,562,000
Cost of goods sold	10,883,000	9,287,000
Gross profit	5,311,000	4,275,000
Operating expenses:
Engineering	811,000	745,000
Selling, general and administrative	3,643,000	3,217,000
Operating expenses	4,454,000	3,962,000
Earnings from operations	857,000	313,000
Other expense:
Interest expense, net	25,000	28,000
Earnings before provision for income taxes	832,000	285,000
Provision for income taxes	328,000	165,000
Net earnings	$ 504,000	$ 120,000
Basic earnings per share	$ 0.10	$ 0.02