Consolidated Statements of Operations (USD $)	3 Months Ended		9 Months Ended
	Jan. 31, 2012	Jan. 31, 2011	Jan. 31, 2012	Jan. 31, 2011
Net sales	$ 2,826,000	$ 2,043,000	$ 8,085,000	$ 7,535,000
Cost of goods sold	2,024,000	1,627,000	5,773,000	5,194,000
Gross profit	802,000	416,000	2,312,000	2,341,000
Operating expenses:
Engineering	165,000	170,000	510,000	326,000
Selling, general and administrative	595,000	700,000	1,867,000	1,827,000
Operating expenses	760,000	870,000	2,377,000	2,153,000
Earnings (loss) from operations	42,000	(454,000)	(65,000)	188,000
Other expense (income):
Interest expense	12,000	12,000	36,000	29,000
Earnings (loss) before provision for income taxes	30,000	(466,000)	(101,000)	159,000
Provision for income taxes	0	0	0	0
Net earnings (loss)	$ 30,000	$ (466,000)	$ (101,000)	$ 159,000
Basic earnings (loss) per share	$ 0.01	$ (0.09)	$ (0.02)	$ 0.02