Ive tried making one out of a simple dc motor. I dont have access to one of those nice offset weights that you see here:
I've run into a couple of issues and I need advice.
Motor choice
I have tried 3 different motors: 5v dc motor, hubsan 3.7v drone motor and a servo. The servo is nice because of its torque. I need to dry seeds so I can plug a battery on the servo and and mcu and program it to run every 1 hour. This is great but an mcu has its own power demand and the battery would need to be large enough to be rechargeable from a solar panel.
Ah solar panels! I remembered I have this little vibrating toy, a cricket, that consists of a very small DC motor, smaller than the hubsan drone motors, with what turned out to be a 0.60V solar panel strapped to its back. This is perfect because it vibrates when sunlight hits it. No bulky battery required. However that small cricket gets trapped in the beans because it's not powerful enough to vibrate through the bulk of beans.
So then I thought of using a hubsan drone motor which is quite powerful. Buy the motor is so powerful from a 3.7v lipo that it flings the alligator clips or eraser parts away.
Then I tried using a larger 5v dc motor and put an alligator clip on its gear tip and it works but I can't just put that in the bean bed because it flings beans out because it's so powerful. Like the hubsan it's not really acting like a vibrating motor.
My questions
1. How can I make the hubsan 3.7v and 5vdc motors into vibrating motors? I need to put them into a container so that they don't end up flinging beans like a catapult.
2. A solar panel is really the best way because it eliminates the need for batteries that must be replaced or recharged. However solar panels are not a current source so they can really generate enough to run a small motor.
I envision something like a 5" diameter ball covered with solar panels with a vibrating motor in the middle?