Condensed Consolidated Statements of Cash Flows - USD ($)	6 Months Ended
	Nov. 30, 2022	Nov. 30, 2021
Operating activities:
Net income	$ 2,561,879	$ 841,681
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation	635,580	637,363
Stock options issued for services	128,437	125,764
Changes in other assets and liabilities:
Accounts and other receivables, net	(1,474,045)	(189,316)
Inventory	393,916	88,563
Costs and estimated earnings in excess of billings	(1,958,902)	(2,385,172)
Other current assets	(186,070)	354,898
Accounts payable	110,351	(284,608)
Billings in excess of costs and estimated earnings	(32,879)	(645,498)
Other current liabilities	(326,699)	82,114
Net operating activities	(148,432)	(1,374,211)
Investing activities:
Acquisition of property and equipment	(1,390,831)	(560,159)
Other investing activities	(2,520)	(7,249)
Net investing activities	(1,393,351)	(567,408)
Financing activities:
Proceeds from issuance of common stock, net	37,889	8,099
Net change in cash and cash equivalents	(1,503,894)	(1,933,520)
Cash and cash equivalents - beginning	22,517,038	20,581,604
Cash and cash equivalents - ending	$ 21,013,144	$ 18,648,084