Note 5 - Product Warranties - Changes in Accrual for Product Warranties (Details) - USD ($)	3 Months Ended
	Jan. 31, 2019	Jan. 31, 2018
Balance at beginning of period	$ 180,000	$ 180,000
Liabilities accrued for warranties issued during the period	137,576	120,308
Warranty claims and costs paid during the period	(127,838)	(81,996)
Changes in liability for pre-existing warranties during the period	(29,738)	(78,312)
Balance at end of period	$ 160,000	$ 140,000