Ez Chargah



By Raymond Chu,

Evan Geometry,


and Johan Arias

Description: The project is a bench that allows people to charge their electronics using solar power! It converts solar rays from the sun into energy that we can use everyday. One feature is a voltmeter, so that users can see the voltage and amperage generated by the sun. It has an interactive moving mechanism that allows the user to swivel and change the direction the solar panel is facing during the time of the day to capture as much of the solar rays as possible. It will also a plaque providing information on solar panels and what people do and build at SETC. Our project is also focusing on bringing a bigger idea of innovation with SOLAR PANELS!, with a hope a cleaner more healthier future.

  Issue: We are creating a cleaner more eco-friendly energy source that will inform people in the community about solar power and inform them about things they can do at the South End Technology Center @ Tent City.  Some problems that this bench can address are:  tPhones that are about to “die”, Tablets that have low battery charges, and other such electronics that need charging in general. This will help youth who often have difficulties trying to charge their electronics when they are out and about in the community or help people who need to make an important call email. 

  Goal: Our goal is to let people experience how easy it is to use a cleaner energy source like solar and to promote the work we do at SETC by creating an eco-bench which uses the solar rays to charge phones. We plan to also enlighten people who pass by by having a plaque with info on the technology being used and the type of things we do at SETC. We also hope the eco-bench will contribute towards community by providing opportunities for people to socialize while sitting on the bench!

  Audience: Our audience are the folks in our South End neighborhood, especially those who live in local housing developments like Tent City and Methunion. We also hope to reach folks who come to SETC and attract people who might be interested in learning and building things at SETC.  We are especially interested in the youth who pass by.   
Three most important things EZ Chargah does:
Provide an interactive eco-friendly energy source.

                            Have a simple bench serve more than one purpose.
                              Educate passersby about alternative energy & SETC.

Technologies and materials: Our project uses:
      Alternative Energy:  solar panels
      Physical Programming:  a voltmeter programmed with an Arduino
      Electronics:  Charging circuit w/Lipo battery, diode, capacitors, resistors & more!
      Digital Design & Fabrication:  Lasercut wood & acrylic mount and info panel 

                                                                         EZ CHARGAH LOGO

ez charga logo
Research: Our research included various sources of information from various other projects and ideas. We used some of the ideas in our project so that we would have a functioning prototype so that we could base our final product off of that. Also, we would use the prototype to see whether or not we were to have a successful experiment. We conducted multiple ideas from various resources and we have started our project based off one of the Instructables. With our second prototype we will be able to determine how to Implement that type of technology into our bench.

                                                                                    Rapid Prototyping #1

On 7.9.2015 we started to create our circuit. We had researched some examples in instructables, we found an example and based our first prototype on the circuit to see if we could actually have the circuit work. When we were done creating the circuit we tested it out but could not get it to work. So we began to run a diagnostics but couldn’t really find the problem in our circuit. We had ended our day with a yet to be working circuit.

                                                                                    Rapid Prototyping #2

On 7.10.2015 we started to work on our voltmeter and the coding behind it, We were working on our circuit for the solar panels. By the end of the day we were able to have both the Voltmeter and the SolarPanel circuit successfully do their jobs. Our SolarPanel could successful charge a phone with ~4.5 Volts and our Voltmeter was accurately telling the amount of Volts being produced from our Solar Panel Circuit.

                                                       ◊ Building an Arduino DC Voltmeter  ◊

Multimeters and voltmeters are essential pieces of equipment when working on any kind of electronics circuit or Arduino project. A voltmeter measures the voltage between two points in a circuit and, with digital electronics, this is an analog range from zero to the level of the power supply (Vcc). Digital voltmeters work by converting the analog value to a digital value using an analog to digital converter (ADC). A typical Arduino has several of these converters on the board, and in this tutorial you will see how to read voltages from the Arduino’s analog inputs and build a voltmeter that measures direct current (DC) voltages.


  • Solar Panels
  • Bench
  • Boston
  • Technology
  • Interactive

3 Technical information sites:


3 DIY projects:
We based some of the info off of these projects for our project:

– It shows how to create a charger, and how it can be charged through solar power with a rechargeable battery case and how you can use it with a convenient Altoids tin.-
Parts we can use:
USB Charging Circuit
Solar Panel 4V or greater
AA Battery Holder
AA Rechargeable Batteries
1N914 Diode
– It shows how to create a charger, and how it be used to charge phones from the sun rays, using solar power as energy and how you can implement it into a convenient Altoids tin.-
Parts we can use:
Solar Panels
USB port
– A solar powered box charger that uses Lithium batteries along with a powerful solar panel to charge phones efficiently and with the use of a eco-friendly energy source.
Parts we can use: 
Solar Panels
USB Charging Circuit – DC to DC Boosting Circuit
3.7V Lithium Battery Charge Controller
3.7V Lithium Battery – 2600mAh or better
6V 830mA Solar Cell (5 Watts)
2.5mm Male Barrel Jack with Wire
Toggle Switch

5 keywords to google:  
Solar, Phone Charger, Bench, Swivel mechanism, Voltmeter – LCD

3 examples of products that have parts like the EZ Chargah:
1.  Solar powered park bench built by MIT students and installed in Boston Parks:
2.  Minty Boost by Adafruit:
3.  http://www.instructables.com/id/Solar-Powered-Cell-Phone-Charger/



  • Clean eco-friendly energy.
  • Resting place
  • Interactive
  • Informative


  • Might be a bit too sunny
  • Won’t Charge as fast as you would want it to be
  • Sitting on the bench may be tedious


  • 2 sentence explanation of your rapid prototype

LCD reference links!

Intro to LCD screens

Adafruit’s Introduction to LCD Screens

Adafruit’s Learn Arduino Lessons 11 & 12 on LCDs


                       (☞゚ヮ゚)☞ Day Logs ☜(゚ヮ゚☜)

[«– Voltage Meter –»]
      Today, we worked on the coding of the Arduino for the voltmeter, we are also working out the wiring of the voltmeter to the breadboard so that we can have it program in function of our solar panel circuit.
We’re currently learning how to code and set up the RedBoard so that it can be implemented with our circuit.
Raymond- Worked on the Wikipedia page.
Evan- Working on the circuit of the Voltmeter, RedBoard, and BreadBoard.
Johan- Working on the coding while also helping Evan with the wiring.
No complications or setbacks so far today.
No obstacles yet.
Technologies incorporated tray would include the Breadboard, RedBoard, and the Solar Panel Circuit.

<\-= Voltage Meter=-/>

       We are currently working on an enhanced version of our voltmeter. This time our voltmeter will be on a ProtoBoard. This is so that it can work with the Solar panel circuit. We are also currently working and finishing our team logo. After, we will work on the structure of our bench and the plaque for it.
We’re learning how to set up the voltmeter with ProtoBoard so that it could work in compliment with the solar panel circuit in telling how many volts the solar panel is producing. 
Raymond- Working on the Logo for the group.
Evan- Working on the voltmeter.
Johan- Working on the Plaque and what information needs to be going into it.
Raymond, Evan, and Johan- Working on the actual structure and design on the final product.
No complications or setbacks yet.
No obstacles to face.
Technologies used today would be the Proto board instead of the perviously used breadboard, and RedBoard.

              /==–X Solar Panel X–==\      

      Today, we are trying to fix the solar panel circuit, we believe that it doesn’t provide enough volts to charge a phone and we used the voltage meter and saw that the circuit lost voltage throughout the way of the circuit. 
We are currently working on the solar panel breadboard circuit.
We’re learning how to setup the voltage meter once it comes in the mail.
Raymond, Evan, and Johan- Working on the solar panel circuit.
Our only setback right now is the circuit, we know it works, but it does not provide enough charge to phones.
Technologies we’re using today would be:
Breadboard and Solarpanels.

-[XX Batteries XX]+

       We are thinking on how to implement the battery holder with the solar panel, that way we could have the device being charged by both solar power and rechargeable batteries. We will have the batteries charged with solar energy when it’s not being used. 
Today, we researched more about how to use the voltage meter and the rechargeable batteries in compliment to each other.
Materials used today:
Lithium Batteries.

[|]– Voltage Meter –[|]

 Later in the day we had received our Adafruit materials for our voltage meter. We researched the instructions on how to set up the voltage meter, and then we began to solder our Adafruit materials so that it could have it be able to use for the breadboard.We are currently creating the circuit for the voltage meter.
Technologies used today:
Adafruit materials

                           [o|– Voltage Meter –|o]

We are now working on finalizing the circuit for the Voltage meter. We are also now waiting for a shipment of chips and lithium rechargeable batteries. After these arrive, we will have it wired together with our solar panel. We will also have to wire together our solar panel with our voltage meter so that we may be able to detect that amount of voltage that the solar panel is producing.
Technologies used today:
Adafruit materials.

<>+<> {[Almost Complete]} <>+<> 

       Today,we have started to work on the mechanism behind the swivel and how it rotates. We have started to sand our swivels so that we may be able to design it later. We have our circuit set up and it is ready to be used once we implement it into our designed box. Lastly, the last things that need to be finished to finalize the project would be: Voltage Meter, Sanding of Swivel, and Laser cutting for both decorative and useful purposes.
We’re almost finished and we have had some minor setbacks but we are very close to making an idea come true. We have used technologies that ranges from all the technologies we have been using to new types such as the Laser Cutter and the Sander.

Completion =◊+◊-◊]⇒
We have completed our project. We have our Solar Panel Swivel
together and our circuitry together. We used the laser cutter and we were able to Press-fit our box dimensions for our project.  We have our plaque ready. The only problem as of right now is our Voltage meter. It doesn’t appear to be able to function, although, everything else we have is complete and if not then near-completion. We have reached our goal and made our idea come to life. We will have our project installed in front of SETC where people can see and interact with it.
20150814_180237 20150814_180154

Our Project outside: 





       ヾ(⌐■_■)ノ♪ Our Idea Brought To Life ヾ(⌐■_■)ノ♪
We have successfully created our project. It is to be shown to the community. It allows others to visualize what kind of stuff is made in the Fab Lab and what type of stuff can be made.

                               ⌈[+]〈Power Meter Process〉[-]⌉

We decided to use the Adafruit Pro-Trinket Power Meter circuit so that people could know the voltage, current and power that is being produced by our EZ Chargah:


This would also allow people to change the orientation of the solar panel so that they can locate the angle between the solar cell and the sun that produces the most power to charge their cellphone.

Even though there is a very detailed and thorough tutorial online, we still ran into several issues!

We started with a RedBoard Uno type Arduino because we ran into issues with the Pro Trinket!  We got the voltages to display on the computer serial monitor, but could not get them to display on the LCD screen.   We started to solve the problem by contacting the Adafruit Education Forum and asking the engineers there for advice.

                           ⌊[                〈/LCD issue〉            ]⌋

The current conflict we are facing as of right now is the voltage meter.  The voltages were unable to display on the voltage meter. We went deeper into the problem and found that it may have been the LCD itself. Our script was producing numbers providing the numbers but our LCD would not produce the numbers needed to show the amount of voltage our solar panels and lithium battery were producing.x