Introduction: Shoji Style Solar Lamp
This Instructable details the making of a Shoji style solar lamp. A scan of the garage revealed everything I needed to make a solar version. This instructable has been entered into the Lamps and Lighting Contest - your vote will be a huge help.
The lighting module is re-used from a solar pathway light, the frame is made from 5mm (~1/4") Luan plywood that I had left over from a cabinet project and the translucent panels are remnants of plexiglass dating back to an even older cabinet project.
Pathway lights have an amazing collection of parts and the cost is really low. If you tried to buy all the parts individually, you would end up paying significantly more for the solar cell, rechargeable battery, LED and charge controller components.
Step 1: Tools and Supplies
- For supplies, a 16" x 16" Luan plywood board was ripped down for the framing components and end caps.
- Elmer wood glue for keeping it all together
- Solar Pathway Light
- Measuring devices (measuring tape, long ruler etc... anything that you are comfortable using.
- Blue painters tape to hold stuff together while glue dries
- 0.5" wood chisel and hammer.
- 3/4" Spade bit and electric drill
- Mitre Saw for cutting the strips to length
- Table Saw for ripping the sheet of ply into strips and for top and bottom panels
- Soldering Iron for adding the relay to enable/disable the lamp
- Magnetic Relay and magnet - Cherry MP201801 or any other magnetic relay
- Welder contact adhesive to glue the translucent panels in place
- 1/16" Plexiglass for translucent panels
Step 2: Ripping and Gluing
If you buy a 24x24" sheet from your favorite wood supply store, make a single cross cut to make a 16x24" piece. The offcut will be used to make the top and bottom end panels. Then rip the plywood sheet down into 16 inch long strips. There are two different widths 0.75" and 0.5". You will need 4 of each width.
The lamp is going to be about 12" high. Use a miter saw to cut the thin strips down to 12". The off-cuts will be used to create the rails of the lamp so keep them after cutting the strips down to 12". Take care with the cuts so that they are all the same length. I stack 4 pieces together, make sure the ends are aligned and then cut. That way I can be sure they are all the same length which is important for a square construction.
Glue the thin strips to the wider strips so that you end up with corner strips about 0.75" in each direction. The thickness of the plywood plus the width of the thin strip will be about 0.75" which is the same width as the wider strip. I used blue painters tape to "clamp" the parts together while the glue sets. Once the glue has had time to set (~1/2 hour), glue the rails in. The rails connect the corner pieces to make a side of the lamp. Use painters tape to secure and allow 1/2 hour for the glue to set.
Measure the inner distance to make sure what the dimensions of the top and bottom panels need to be. The actual size will depend on how accurately you cut the strips so it is always good to measure before cutting the top and bottom panels to size. cut the top and bottom panels to your actual measured dimensions. Mine was about 4.75" square.
Measure the diameter of the solar module and draw a circle in the center of the top panel. The idea is to have the solar panel press-fit into a hole in the top panel. I used a 1/2" wood chisel to slowly work my way around the circle until I eventually cut through to the other side. Don't pound the chisel all the way through on the first round or you will rip wood instead of cutting it. You can also end up splitting your panel. Use a backing piece of wood to avoid damage to the chisel when you do eventually break through.
Know use a file or sandpaper wrapped around a thickish dowel to smooth the hole and check for fit with the solar module. Work carefully and slowly until you get the module to fit tightly through the hole. By now, glue should be set on the frame sides.
Work carefully because the glue will not reach full strength for some time and glue the base panel into the frame as shown. I also cut some 3/16" strips of wood to glue underneath the base panel to provide additional support. I ended up gluing these strips to support the top panel as well.
With the base panel in place, glue the remaining rails in as well as shown in the last picture. There is no magic to this - just tedious and careful work. I used a clamp and painters tape to keep everything together.
Use a set square to make sure everything is aligned correctly. Once the glue sets, there is no way to adjust anything. The frame should be complete after the glue sets.
Drop the top panel in to check for fit. Adjust the fit with sandpaper as needed.
Step 3: Constructing the Base
The original plan was to have the lamp without a base but it didn't look right. The pathway light has a stainless steel support tube about 3/4" (20mm exactly for the lamp I used) in diameter so this was used to connect the lamp to the base to create a floating look.
Working carefully, make the hole in the center of the base panel. It would have been easier to make this hole before gluing everything together but this was a last minute design change. Use sandpaper wrapped around a dowel to adjust the dimensions until the stainless steel tube fits snugly through the hole.
To provide additional support, make a whole in the center of the module cutout and then adjust the hole using sandpaper to get a tight fit. Making sure the tube is at right angles to the lamp, glue the extra support circle to the base plate.
The base was constructed from two 5" long pieces of 2 1/2" poplar wood. You could use a piece of 1/2" or 3/4" plywood as well. I used a Kreg jig to create two pocket holes underneath the base to screw the two pieces together. You could just glue the pieces together, clamp them and wait for the glue to dry. Whatever method you use, once the parts are properly joined (in case of glue give the glue time to set) use the spade bit to cut a 3/4" hole in the base for the stainless tube. Adjust the hole using sandpaper to get a snug fit.
The base and lamp can then be assembled. At this point, the base and lamp are being held together using a tight press fit. When the final height is determined, epoxy glue will be used to set the final connection height.
Step 4: Translucent Panels
The side panels started out as a sheet of clear 1/16" plexiglass. A random orbital sander with 320 grit sandpaper was used on the one side to create a frosted look. I did this for another project way back when and still had a piece lying in the garage. You could use Frosted Glass spray paint equally effectively.
The panels are cut to size on the table saw. Be careful and wear protective eye-wear Bits of plastic will be flying up at you at supersonic speed - you do not want to get hit in the eye. The safer way to cut plexiglass is to score a line and then snap it in a similar way to cutting glass. A jig saw can also be used for this.
To secure the panels in the frame, I used Welder contact adhesive. Just a small bead around the edge of the plexiglass is all that you need. The glue sets quickly.
Step 5: On/Off Switch
The lamp is destined for my daughter's bedroom so we needed an on/off switch. A magnetic relay is a nice solution as it avoids making holes in the lamp. You can enable the lamp by placing a magnet near the relay. To turn the lamp off, remove the magnet.
Remove the base of the solar module and drill a 1/8" hole for wire access. Carefully remove the printed circuit board from the base and then cut one of the led terminals roughly in the middle. The relay gets soldered to the two cut legs so that the current path is from the battery, through the relay and then to the LED. When the magnet is removed, the relay is open and the LED remains off. Cutting power to the LED ensures that the battery charging circuit remains functional.
Step 6: Final Assembly
All that is left to do is re-attach the base, place the top panel in position and you are done. If this is going to be used outdoors, it is a good idea to use polyurethane to protect the wood from damp. I wouldn't leave it out in the rain though.... it is wood after all. You could also paint it, stain it etc. If you do plan to leave it outside, make sure to caulk the top panel and around the module to prevent water ingress. It would also make sense to paint/stain/clearcoat before assembling the translucent panels.... but that would be thinking ahead.... and I didn't!
Enjoy your lamp!