Star Trek: 10 Things You Didn’t Know About Janice Rand
6. Her Over-The-Shoulder Camera Led To The Tricorder
The image of the tricorder, and particularly The Original Series version of it, is so attached to both Dr. McCoy and Mr. Spock in the public mind that anyone would be forgiven for believing it was specifically invented for them. While the tricorder would certainly become associated with both as time went on, it actually had rather humble beginnings - as an accessory for Yeoman Rand.
Gene Roddenberry suggested to Robert Justman, in a memo from 1966, that Rand be provided with an over-the-shoulder recording device, one that would double up as a scanner, so that she would be as able to record Captain's Logs, etc while on an away mission, as she would have been on the bridge.
Roddenberry also openly stated that it would be a fun accessory for 'female-type children' to have as well, which certainly indicated he intended the original device to be something akin to a specifically targeted toy for girls, as opposed to one of the most important devices in Star Trek's history. Of course, the world has a funny way of combing these things!