Since i have been a scout for 12 years, a few years ago i decided to build a portable speaker powered by the sun. This project recieved a lot of great comments since it was super cool and usefull, But it still had a lot of room for improvement. So here we are a few years later with an assignment for school (HOWEST Belguim) to design something made out of flat materials. For me the ideal occasion to redesign somthing that i made years ago without some of the equipment that i now have at hand. To build this project you need the following tools that could be found in every fablab or hardware store.
- Laser cutter
- Hot glue gun
- Wood glue
- Solering iron
- Paint brush
- Can of stain ( with or without color)
Also since there is a lot of electronics involved you will need to order some parts or find them locally.
Also it is adviced to have knowledge of electronics and soldering before you start since you have to "mod" a few components.
- 5v amplifier : got mine on ebay , Just look for 2x3W 5V amplifier
- USB power bank ( as high capacity as you can find) : got mine at the action for 10 euro's
- 2 double on/on rocker switches : got mine locally
- Usb female panel mount port : got mine from an old computer
- Solar panels (mine are 13 - 15 cm/ 5V 500mA) : bougt them on ebay
- USB power meter (optional) : got mine from action
- 2 regular rocker switches : had them already
- 3,5 mm headphone jack : stripped it from an old headset
- 3,5 mm female jack panel mount : bought it on ebay
- DC power jack : bought it on ebay
- USB bluetooth audio reciever : bought it on ebay
- 2 speakers : found mine in the garrage ( schould be easy to source)
- A transistor or mosfet and the required resistor
- USB car charger: got mine at action
- 5V led strip
You can decide to leave some of the components away or even add some of your own.
I recommend reading the whole instructable before building to get a good understanding of why i used some components before you leave them out. if you still have courage after this washlist of components proceed to the next step.
Step 1: Testing the Setup
Before we start building and our case and solder everything together for real it is Always a good idea to test your setup before going any further. So i started by breaking my usb power bank and getting the components out.
keep in mind that the orange " batteries" are lithium cell's which when handled inpropperly could set on fire.
- Do not short them out
- Do not use them without the charge cirquit
when my batteries where out of the box i connected the bluetooth usb stick, amplifier and speakers together and played a song. Everything worked fine so i could move on to the next step.
Step 2: Designing and Building the Enclosure
Building a nice enclosure is verry easy when you have a lasercutter available.
Measuring and planning is still verry important. The base of my speaker is a cube, the sides of this cube are the length of the solar cell's +1cm so the can be positioned like a flower and be put away on the back of the system.
The diameter of the speakers is also somthing you need to keep in mind.
Most of the other components can be placed afterwards since all the electronics are on the front panel.
When you are sure of your design laser it. I used a sheet of 8mm poplar. Glue the parts together while clamping it together so the glue can bond propperly. When the glue is dry you can finish the box with stain. I used a stain with an orange effect to make the wood grain pop.
To build the solar panel enclosure i used 2 parts since the laser cutter can't cut in the 3rd dimention. The outline was made of 3.8mm poplar multiplex while the back cover was made out of 1.5mm poplar laminated with oak.
Before gluing the solar panel in with hot glue i soldered a 3 pin connector to them. The outher wires go to negative while the middle one goes to the positive wire. Using a 3 pin connector ensures that we do not have to worry about the orientation of the connector.
Step 3: Soldering the Parts
Depending on what configuration you use you will have to solder the parts in a specific way so everything is powered and wired correctly. I cant predict which components you use but you can use mine as a guide or a base to start with.
Firstly i started with my power circuit. To alow the solar cell's to work propperly and provide enouf power i connected them in series acompanied by the required diode. At the end of the positive lead another diode was added to protect it from reverse voltage. Both the output lines from the solar cell's and the DC connector where then connected to the switching regulator (mine could handle 24v found in trucks so i can use a power supply between 5 and 24 volts to charge the unit). on the outputs of the regulator i connected the usb power meter so i can visually see how much vultage and current the solar panels provide.
To use a power bank and still be able to charge it requires you to use a switch since power banks do usually not like to be charged and discharged at the same time. i used a dual ON/ON switch to switch the positive lead from the solar cell's/DC adaptor to the rest of the unit. The second on/on configuration is used to connect or disconnect the positive lead that charges the battery. Since the charging/discharging ground connection of the battery cannot be connected i used transistors as a switch between power bank and ground. The base of the transistor is connected to the positive charge lead so the ground is only connected when the unit runs of external power and alows the battery to be charged.
Next up i provided all the components like bluetooth usb with the required power, adding a switch to have the posibility to turn the speaker and lamp on and off.
finally i had to wire the audio leads. Using a dual ON/ON switch alowed me to switch the input for the amplifier between bluetooth and jack. This is easely done by connecting the input left and right lines of the amplifier to the center pins of both switches, while conecting both left and right output lines of the jack and bluetooth stick to the remaining leads. Make sure to connect the wires that belong together on the same side zo you activate both left and right of the same connection in both switch positions.
EXTRA OPTION: my power pack had led's installed to show the battery percentage. I re-wired the leds to other leds i installed on my front panel. not all battery packs will have this option.
Step 4: Adding Velcro to Hold the Panels
Since i want the solar panels to stay in place when they are not used i added velcro to strap them in place. while used the notch on the top will provide extra strength to the panel while the bottom ones support and align the panels while not in use. The velcro strips are double sided so it does not mather which one goes on top. to secure the strips in place i slided them trought the center notches and glued them in place with a lot of hot glue.
Step 5: Testing and Enjoying
After every step in this instructable is finished there is only one thing left to do.
Test the system completely. If there are some problems try to solve them until there are none left.
When everything works as planned you will now have a super cool speaker to take with you on camping trips or just to use outside while enjoying a cold beer in the sun.
I hope you enjoyed my instructable, feel free to ask questions ans follow me for upcomming projects.