Attaching a pager or phone type vibrator to this seeder would make it work much better as the seeds would bounce around and create a more fluid flow out of the spout.
Scavenging an old pager or phone for a vibrator/motor would be a pain, but I found an essentially free and easy alternative. A disposable vibrating toothbrush. The one I used was an oral b pulsar, but there are other generic brands out there. If you buy one of these, you will find out the battery doesn't last as long as the bristles. But they don't make the batteries easy to replace. Once you figure out how to replace the batteries without ruining the toothbrush, it lasts a lot longer. After the brush is toast you can use the vibrating motors for nifty little projects like this.
Step 1: Dismantling the toothbrush
The end of the toothbrush unscrews easily enough, but that just exposes the tip of the battery and the negative contact. Don't bend the contact. Basically, you cut a hole in the rubber backing 12 ridges down from the top with the sharp tip of an exacto knife. You will know it when you find it because there will not be any hard plastic behind the rubber in that spot. Inside the hole you should see a small red wire if your lighting is good. Take a small jewelers screwdriver or other small pointy object and push in the two pins or clips on each side of the red wire while pulling on the side of the battery contact/holder (not the end - you don't want to bend it). Be careful you don't damage the red wire. If all goes well, the whole electrical assembly will slide out the end of the toothbrush.
Now you can use the tiny motor/vibrator for some other project, replace the battery with a fresh one and continue using the toothbrush, or use the toothbrush with a fresh battery for a different use like we will be doing.
Place a new or recharged AAA battery in the holder, and, while making sure the electric assembly is aligned properly with the toothbrush shell, slide it back into the shell. Test the switch. If OK, screw the toothbrush end back on. The toothbrush end is double threaded, so if the end ends up backwards on the toothbrush, unscrew it until it clicks into the alternate threads and screw it back on. Test the switch again. If you bent the battery holder, the toothbrush end will twist it and cause it to fail.
Don't feel bad if it doesn't work right the first time for you. It took a few tries for me to get it right and the brushes are cheap.
Step 2: Cut and glue
By cutting off the head, you are removing energy absorbing mass, which you will replace with the mass of the seeder.
Place the toothbrush sideways on the back of the seeder so the motor is right about where the seeds flow out of the notch. Use hotmelt glue gun to glue the perimeter. Having the handle sideways allows you to turn it off and on while still leaving the hole you cut accessible in case you need to replace the battery again. The handle end will stick out a couple inches opposite the seed funnel opening giving you more to hold onto while guiding the seeder down the row.
Click on this link to see it in action!