Any know anything about a planet jr planter?

Planet jr can plant just about anything, the plates allow one seed at a time to pass through, they index to the planter box, do not rotate. the seed above the plate is agitated, and the seeds drop through the  hole. to move to a different size hole, there is a spring loaded snap, and an index hole, that holds the plate stationary.  only problems are with really small seed, like carrots.  Some seed co's sell pelletized seed, that has 1 or 2 seed in a pellet, of inert material, uniformly sized, to make seeding the small seed easier...

Mine works GREAT for my garden. For years I've used it for green beans. This year i planted sunflowers and a small patch of "Indian" corn.
 Seed spacing may be a bit close in some case but that's what a hoe is for
I save my own seed for whatever I plant with it.
 I got my planter at an estate auction in about 1977. I gave $1.50 for it but had to make my own handle. I guess it must have been used with a tractor. Some day I will make a row marker for it.