At least in Bulgaria, people go for whatever the word sounds like. Rough rule of thumb is, words that end in -a tend to sound feminine, words with -o tend to so

At least in Bulgaria, people go for whatever the word sounds like. Rough rule of thumb is, words that end in -a tend to sound feminine, words with -o tend to sound neuter. So I'd say едно Ардуино or one neuter Arduino.