Solar Display Case

This project is being put on hold while I work through challenge two of the Hackaday prize, but mark my words! You haven't seen the last of the Solar Display Case!

It seems to fit right in, doesn't it?

I have found an answer to the weight issues! In the last log, I was contemplating using a new case to house the components. Since then, I have been scouring online retailers looking for a case that:

1. Had the right dimensions to fit the three solar panels inside of it, and had enough surface area on the exterior to hold the two on the outside.
2. Could have enough room left over after storing the monitors and panels to house the 18650 battery cell array, solar charger, and IO panel.
3. Ideally be weather resistant, at least IP67.
4. Had a feature that could address the weight issue.
5. Could be purchased in bulk at a low price to ensure production capability.

I believe I found the perfect candidate. The Solar Display Case design has evolved to support rolling much like a suitcase. This makes the SDC more accessible to various users who cannot lift as much weight with just their wrist. My favorite part about this new case is that it satisfies all of the above qualities I was searching for, and it can still be used as a briefcase in situations where rolling isn't possible. Now that I have a clearly defined plan, I am going to put together a component list with pricing and start assembling v2.0. More updates to come!

One of the obstacles in this project is providing added functionality in a portable package. Weight is an aspect of portability, and with v2.0 we are adding more features, which in turn adds more weight. The increased battery capacity is going to account for most of the weight in the project, coupled with the weight of the displays and solar panels it is going to be very heavy without additional modification. Once I have all of the raw materials, I will have to hack the existing frames and remove as much weight as possible. Constructing a new screen frame for each monitor with the solar panel actually built in is most likely going to be my best bet as far as reducing the physical size and weight. These frames can be 3D printed or crafted from carbon fiber as well. v2.0 might even find itself in an entirely new case, possibly a waterproof one like below or a custom fabrication that uses the solar panels as the case structure itself! I'm exploring all my options!

Overcoming challenges is always a part in every project, and in life. You can let yourself get frustrated, or you can have fun solving the problems as they come. The latter solution is by far the more productive option, and will lead to a much better experience building your project, and a much better end product.

For now I have decided the most open solution to the source display issue is to wire the displays to three female HDMI ports located in the bottom of the case. I want to keep searching for a one-cable solution but to be safe I want this to be the main design until my research provides a better one. I have also included the standard wall outlet for charging a laptop or powering a device.  This will allow the user to use their own dock or connect other devices with ease. I also am going to use an assortment of 18650 batteries in the bottom of the case connected to the solar charge controller. The location of the solar charge controller is not final, but is just to illustrate it's presence in the project. A panel will be laid over the 18650 batteries with fans on the top to keep them at a safe operating temperature.

The addition of a third monitor now renders the HDMI to USB adapter unusable since it only supports two monitors but I look at this as an opportunity to make my project even better by making the hardware even more open. I’m considering options so far that will allow the production of the case to be scaled effectively. I’ll keep everyone updated on my progress!

For the third monitor in my project, I am going to use a screen from an old laptop with a bad motherboard to continue illustrating the importance of re-use and green technologies. For the sake of time, I will be ordering a driver board for the screen online, but Arsenijs has a really cool and comprehensive project all about laptop display reuse that you can checkout for making your own driver board and understanding more about the art of bringing new life to any laptop screen. My plan is to have the display be facing the user (obviously) with the solar panel being the rear of the screen assembly facing the sun to provide power to the battery. The driver board for the laptop display will be sandwiched between the two in order to hide the cables. I will likely need to build a frame to hold everything in place. Here are some new design schematics!

I found this 20 watt solar panel with dimensions that will fit perfectly inside and outside of the case:

This wiring diagram that I made based on examples from alternative-energy-tutorials.com (link) shows how to increase the total wattage of solar output by wiring the panels together in parallel or series. 

Basically by changing how I wire the panels together, I can control the voltage and amperage of the solar output which will increase the overall wattage too. My current portable battery is only rated for 5 volts and 2 amps of input so I will need to change my power source. This is a good opportunity to increase the battery capacity of the system which will increase the amount of time it can be used, and also the power delivery options available to me. With this change I have decided to commit to configuring the system to allow charging of a laptop as well. Stay tuned for more updates!

I have the base schematics for the second version completed, upon testing the prototype I found that the single solar panel is not sufficient for keeping the monitors charged. v2.0 Strives for 100 watts of solar energy output by affixing solar panels to the backs of all of the monitors (including an additional third monitor that will be in the second version) and to both sides of the briefcase itself. This should be more than enough power to keep the case operational much longer, and maybe even enough power to provide a charge to a small laptop as well. Enough talk! It's time to get to work.

PHEW! Just in time, I was able to pull the project together and make something that could really impact the way that people work. The finished product is even more impressive then I could've hoped for. I experimented with different source device configurations and found a whole new level of flexibility within my project. Through my experimentation, I realized (and later confirmed with testing) that you can expand the device to run up to three ADDITIONAL monitors for a total of four displays in a portable form factor with minimal changes so long as you have the hardware available. Enjoy the beautiful pictures below!