Simple Solar Bots (BETA!)

By Alex Nathanson updated on 9/27/2019

For a brief introduction to some of the terms used in this article, check out the glossary section.

This tutorial is in beta. The content is accurate, but will continue to be reworked for clarity and accessibility. Additionally, visual design elements and media have yet to be added.

This project uses upcycled solar cells, wired in series, to create a small solar panel that can run a small vibration motor. Variations on this project can be made by substituting an LED or piezo transducer for the motor.

The solar cells are wired in series circuit. A series circuit means all the cells are connected in 1 line, like cars on a train. The positive side of one cell connects to the negative side of the next cell and so on. When all the solar cells have been wired together you should have 1 loose positive wire from the first cell and 1 loose negative wire from the last cell.

This is a direct drive system, which means that there is no power being stored.

Each cell can produce about .5 volts. The amperage that can be produced is determined by the cell’s surface area; large cells produce more power.

Each cell will have 2 solder points, one on the top and one on the bottom.

The bottom of the cell is positive. On the bottom of the cell there will be small rectangular pads where you can solder to. If your cell doesn’t have any small rectangles it probably wont work for this project and you should replace it.

The top is negative. On the top of the cell there are typically small horizontal white lines branching out from a slightly thicker white line. You can solder to the thicker white line. If there isn’t enough space to solder to, you should replace the cell.

The wire we use for wiring solar cells is called tabbing wire. Tabbing wire is flat so that the solar cells can lay as even as possible. Tabbing wire is not insulated, which means that if it comes in contact with another wire or cell it will conduct electricity and may cause a short circuit. It is OK to glue on these wires.

  • solar cells
  • tabbing wire
  • substrate (foam board, balsa wood, cardboard, etc.)
  • load (vibration motor)
Useful tools:
  • wire cutter
  • wire stripper
  • soldering iron + solder
  • pliers
  • hot glue gun + hot glue sticks
  • solder flux pen
  • multimeter
  • box cutter (or other cutting tool for the substrate material)
  • tweezers (optional)
  • cutting mat (optional)


  1. Select Solar Cells
    1. Select cells that are big enough to produce the power you’ll need.
    2. Make sure there’s enough space on the top and bottom to solder to.
    3. Find cells that are aesthetically pleasing. One of the great things about using these upcycling “broken” cells is that you can find cool shapes.
  2. Prepare Substrate
    1. Cut a piece of the substrate material that is big enough for all of your solar cells.
    2. Carefully lay out your cells on the substrate.
    3. Identify where your wires are going to travel. Remember, the bottom of one cell will connect to the top of the next cell in series.
    4. It can be helpful to trace them or mark their locations and the direction of the wires for later.
  3. Solder bottom of cells
    1. Carefully flip over your cells.
    2. Cut 1 piece of tabbing wire per cell.
    3. Using the flux pen, apply flux to the spot you are going to solder to.
    4. Solder the tabbing wire to that spot.
  4. Attach 1st cell to substrate
    1. The first cell you glue down is the cell that will have a loose bottom (positive) wire. This way, the wires build up and it will be easier to work with.
    2. Using the hot glue gun, apply glue to the bottom of the cell. Don’t apply too much, because it will make it very difficult to remove if it breaks later.
    3. Once it’s glue down, use the multimeter to test either voltage or continuity between the top of the cell and the wire sticking out from the bottom. This will confirm that the solder connection is still good.
  5. Attached next cell to substrate
    1. Using the hot glue gun, apply glue to the bottom of the cell. Don’t apply too much, because it will make it very difficult to remove if it breaks later.
    2. Once it’s glued down, solder the loose end of the wire to the top of the previous cell. Remember to use the flux pen on the solder point on the top of the cell before soldering.
    3. Don’t hold the soldering iron on the cell for too long, because the heat may cause the wire underneath to disconnect.
    4. Use the multimeter to test either the voltage or continuity of the entire string. This will confirm that the solder connections in the whole string are still good.
  6. Repeat step 5 until all cells are wired in place.
  7. Test the entire string and if its good, apply extra glue around the edges of all the cells. You can also apply glue on top of the wires if needed.
  8. Solder the final top wire
    1. Test this connect with the multimeter.
    2. Glue part of it down so if it gets bumped it won't break the solder connection.
  9. Connect the load
    1. You should now have 2 loose wires, a positive connected to the bottom of one cell and a negative connected to the top of another cell.
    2. Solder the negative wire to the negative side of the load
    3. Solder the positive wire to the positive side of the load

Subscribe to our mailing list
instagram icon