Again Toriyama contradicting himself. In this interview (in 2014) he makes it clear that who created the scouters were the Tsufruians and an engineer named Gichamu modified them for Freeza's army:Super Saiyan Swagger wrote:Kikono is a very old Freeza Force member and is a genius scientist who worked for King Cold. He created the scouters, armour and spacecrafts.
http://www.kanzenshuu.com/translations/ ... outers-qa/
It seems that there are old- and new-type scouters, but are there various other types of scouters as well?
They’re the same in terms of features, but a variety of different aliens wear them, but there are a bunch of different types of attachment parts depending on the position of the ear. If you’re a soldier in Freeza’s army, you can have one made to order to fit your ear. The different screen colors can be chosen to fit the peculiarities of different aliens’ eyes, or to suit one’s tastes. Also, dual-eye types exist as well. Incidentally, its inventors were the Tsufruians, the original inhabitants of Planet Vegeta who were wiped out by the Saiyans. Originally, it was a device for the purpose of guarding against enemies and beasts, but Gichamu, a highly skilled engineer in Freeza’s army, laid eyes on it and made modifications for concrete battle power numbers and telecommunications abilities, and soldiers began making use of it to carry out offensives.