This instructable is on a small project on making a solar powered pop-up paper house. The paper house will convert the light it receives into energy for its interior lighting, lighting up the LEDs inside the house. At the end of this instructable, you will be able to make this very simple little paper toy perfect as a decoration just sitting in your room or as a gift sent to a friend in the form of a pop-up card.
Step 1: Materials used
- Pop-up paper house cut out from a 190gsm paper (you may download the pattern in the next step)
- 2 LED, flat and bright models preferred (I used 1 Red and 1 Blue LED)
- 14 pieces of 52mm x 6mm small solar cells
- Some conductive ink
- Some instant glue
- Some copper tape
- Elmer's glue
- Pen cutter
- Random metal rod
Step 2: Preparing the paper cutout
The first image is the very simple paper pattern needed in this project. I have the paper pattern prepared by pepakura designer 3, a very handy software for preparing paper pattern. Although it's not a free soft, they offer a free viewer that can display and print their special .pdo files.
For this paper house, you can just download the .jpg file and have the pattern printed onto a thick A4 sheet (around 190 gsm). There are two house in one sheet just in case anything bad happens when you cut out the pattern.
Pay closer attention to the second photo and you will see that one window was not cut out. That window was left there in order to make the inside of the house darker, creating a better contrast when the light is up. Instructions on how the holes on the two roofs are cut out will be found in step 4.
A dummy house shows how the lower layer of the roof is connected to the house's wall, as well as how the house is flattened. The missing upper roof will be glued onto the trapezoidal flat region of the lower roof later on but, don't do that now as we will still need to do some circuit connection on the roofs first.
After having an idea of how the house is to be folded, you can now use the pen cutter to create the fold lines along the dotted lines by carefully cutting just a very thin surface layer of the thick paper. This scribing action will aid forming the house's shape as you pops it up from a flat pattern. Note that if you wanna do a mountain fold, you scribe the upper surface of the paper. and if you wanna do a valley fold, you scribe the back side of the paper. In this model, only two lines on the lower roof and one line at the door need to be scribed underneath. All other lines are scribed on its upper surface.
Step 3: And here comes the solar panel
To connect the solar cells in series, I connect successively the bottom side of a cell to the top side of the other. Solar cells are not that good a conductor. To aid the current flow, bus bar, the more conductive white region on the solar cell, is printed onto the cells. That is why you can see that I am only applying the conductive ink onto the bus bar. After applying 2 dots of instant glue onto the cell edge and a dot of conductive ink onto the edge of the bus bar, I placed the second solar cell onto the first with a 1mm overlapping. Repeat this for 5 more times and you will get a panel consists of 7 cells. Note that the more you overlap, the less of the cell is exposed to sunlight and thus the less current you can get from the cell.
Before I put the panel onto my paper house, I measured its current under a light just to see if all connections are good. My panel gives 80 something mA when not shaded by my fingers but you can still see 57.6 mA when I took the photo with my other hand.
Don't worry too much if the current reads zero. It may only be caused by a bad connection or two. If this happens, identify the bad connection with an aid of a multimeter and use a hot air gun to soften that connection. Then, pull the connected cells apart and redo that connection. You may also simply do another panel from the beginning instead, if you prefer so.
Step 4: Under the roof
Now let's cut out the holes on the upper layer of the roof. The holes near the center fold line shall best be aligned with those on the inner layer for ease of connection. Those holes shall drift away from the center fold line for just a bit due to the paper thickness. Then, use the solar panel prepared in the last step to measure the separation between the two holes on the upper layer of the roof. Holes shall be directly under the first and last solar cell. In the photo attached, you can see that there is a shaded region between the 2 holes on one side of the upper roof. That shaded region corresponds to the second hole of the lower layer. You can then cut out a strip of copper tape of around 2-3 mm wide and connect the holes at the sides and at the shaded regions as shown in the photo. This can then be glued onto the lower roof with some random glue. Instant glue will do this just as well but emer's glue will certainly do a better job.
Step 5: Time to play with the conductive ink again
Then, position the bottom side of the last solar cell of the solar panel to the conductive ink. Note not to let the ink contact with the back side of other solar cells or you will short the solar cells in contact. Remember to flip over the assembly to ensure good positioning. Additional conductive ink might also be added to make a better connection.
When both panels are connected, I flipped the assembly over and dipped the legs of the 2 LEDs into the pool of conductive ink located at the two holes on the lower roof. The conductive ink in the two holes near the center line goes directly to the bottom of the first cell in the solar panel. It is very important have the LEDs connected in the right polarity. A wrong polarity will just give you a dead LED. If you don't know it already, the bottom side of a solar cell is actually the positive side. If you are sticking the solar panel onto the roof in the same direction as I did, the positive side should be the lower end of the panel.
With the LEDs in places, a complete circuit is formed. I held it under a light to confirm a working assembly before I glued it onto the rest of the house. This step also completes the assemble of this paper house : )
Step 6: Finish!
- Additional solar cell
- Drifted LED position
- Making a pop-up version
That's it. Hope you enjoy this paper house and my first instructable : )
Step 7: Let's Pop it up
Basically, all you need is a thick backing paper of around 20cm x 10cm, with a fold line at the middle and little mark right at the center. Then, apply Elmer's glue to the back of the triangle (marked with a blue dot) and align the edge of that triangle to the center point of the backing as shown in the photo. Then, apply glue to the top triangle and close the backing. Before the glue dries completely, try to open the the backing paper to see if the house opens well. You may need to adjust so a bit due to paper's thickness.
You will still need to put the upper roof and the solar panel on before you can get a good looking pop-up house but as mentioned earlier, the thickness of solar panel and the LED makes this a very poor pop-up house. I suggest you to go for either a pop-up house (with no LED and something else replacing the solar panel) or just solar-powered paper house.
Enjoy : )