CONSOLIDATED CONDENSED STATEMENTS OF OPERATIONS - USD ($)	3 Months Ended		6 Months Ended
	Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2018	Oct. 31, 2017
CONSOLIDATED CONDENSED STATEMENTS OF OPERATIONS
Net sales	$ 4,874,000	$ 4,684,000	$ 9,347,000	$ 9,214,000
Cost of goods sold	3,200,000	3,322,000	6,194,000	6,596,000
Gross profit	1,674,000	1,362,000	3,153,000	2,618,000
Operating expenses:
Engineering	313,000	273,000	615,000	539,000
Selling, general and administrative	1,290,000	1,358,000	2,501,000	2,644,000
Operating expenses	1,603,000	1,631,000	3,116,000	3,183,000
Income (loss) from operations	71,000	(269,000)	37,000	(565,000)
Other expense:
Interest expense, net	24,000	13,000	48,000	25,000
Income (loss) before income tax expense (benefit)	47,000	(282,000)	(11,000)	(590,000)
Income tax expense (benefit)	15,000	(111,000)		(226,000)
Net income (loss)	$ 32,000	$ (171,000)	$ (11,000)	$ (364,000)
Basic income (loss) per share	$ 0.01	$ (0.03)	$ 0.00	$ (0.07)