Note 11 - Segment Information - Summary of Segment Information (Details) - USD ($)
12 Months Ended
Mar. 31, 2022
Mar. 31, 2021
Revenue from Contract with Customer, Including Assessed Tax $ 3,206,594 $ 3,090,631
Segment operating (loss) (1,129,314) (680,478)
Total assets 3,250,897 5,214,099
Chemical [Member]    
Revenue from Contract with Customer, Including Assessed Tax 1,319,578 1,244,361
Segment operating (loss) (443,587) (263,061)
Total assets 1,332,867 2,033,499
Electronics [Member]    
Revenue from Contract with Customer, Including Assessed Tax 1,405,594 1,328,719
Segment operating (loss) (662,808) (457,372)
Total assets 1,430,395 2,294,203
Engineering [Member]    
Revenue from Contract with Customer, Including Assessed Tax 481,422 517,551
Segment operating (loss) (22,919) 39,955
Total assets $ 487,635 $ 886,397