Note 5 - Product Warranties - Changes in Accrual for Product Warranties (Details) - USD ($)	3 Months Ended
	Jan. 31, 2022	Jan. 31, 2021
Balance at beginning of period	$ 75,000	$ 85,000
Liabilities accrued for warranties issued during the period	55,243	50,251
Warranty claims and costs paid during the period	(7,894)	(18,348)
Changes in liability for pre-existing warranties during the period	(47,349)	(31,903)
Balance at end of period	$ 75,000	$ 85,000