Consolidated Statement of Operations (USD $)	3 Months Ended		9 Months Ended
	Jan. 31, 2015	Jan. 31, 2014	Jan. 31, 2015	Jan. 31, 2014
Net sales	$ 3,675,000	$ 2,938,000	$ 9,471,000	$ 9,804,000
Cost of goods sold	2,667,000	1,934,000	6,533,000	6,199,000
Gross profit	1,008,000	1,004,000	2,938,000	3,605,000
Engineering	203,000	147,000	557,000	434,000
Selling, general and administrative	745,000	798,000	2,366,000	2,563,000
Operating Expenses	948,000	945,000	2,923,000	2,997,000
Earnings from operations	60,000	59,000	15,000	608,000
Interest expense, net	7,000	8,000	21,000	26,000
Earnings before provision for income taxes	53,000	51,000	(6,000)	582,000
Income Tax Expense (Benefit)	25,000	20,000	2,000	223,000
Net Income (Loss) Attributable to Parent			(8,000)	359,000
Common Stock [Member]
Net Income (Loss) Attributable to Parent	$ 28,000	$ 31,000	$ (8,000)	$ 359,000
Earnings Per Share, Basic	$ 0.00	$ 0.01	$ 0.00	$ 0.06