The panel is only designed to run a small processor and LCD, which only require a tiny current to operate. Even a small motor needs a far larger current just to spin without a load. Even if you store the energy in a capacitor, I wouldn't expect a full second of operation from a full days charging.

You are ultimately limited by the power being received by the solar cell, which averages about 1400W per square meter from the sun, and indoors will be far less.

Try salvaging larger solar panels from old garden lights, these should at least give you enough power to charge a small battery pack.

Now I got a question - would it be possible to make larger cells out of a large pile of cells recycled from calculators and such items?

I mean I see calculators being thrown out all the time.

This panel will work for your junk bot. this website sells parts for "beam bots" also known as junk bots. The link I provided here gives plans for building a Miller Solar Engine and also lists the parts. Best of luck. also solarbotics has lots of parts and instructions so keep looking around that site.

https://solarbotics.com/download.php?file=58