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Teaching a DIY Solar Charger Project, remotely

Along with my math preps, I also taught a venture-project class this quarter. I had planned a very hands-on project and purchased a LOT of supplies for the students to make solar lamps, solar chargers, and solar cars. When we shifted to remote learning, I decided to try and make this project run, if a little scaled down. I split the kids up into groups, and a group of 6 middle-schoolers got assigned to be on the Solar Charger team. I have never built this project with kids before and have spent the past few years trying to get the electrical design nailed down. But I really wanted to do this project. All of our ventures focus on community needs, and we’ve worked with the FoCo Cafe and Homeward Alliance over the years to bring donations to the homeless. They’ve mentioned before how awesome solar chargers would be. At the shelters, people often crowd around outlets so they can charge phones. For people experiencing homelessness, if they have a phone, it’s a crucial communication tool- a connection to the world. But if you don’t have a permanent place to live, having access to electricity can be a challenge.

Over the past year, I settled on a design for a solar charger using 18650 batteries (these can sometimes be found in laptops and vape pens, but I bought them off eBay) and a TP4056 charging circuit. It’s not a perfect solar charger. If you plug the circuit into the wall using the micro-usb port, the batteries hold enough charge to charge your phone more than once. Although the batteries say they’re 3.7v, they can be charged up to 4.2v with a wall charger. However, if you charge the batteries using the solar panels, it seems the current never quite gets high enough to charge the batteries that last little amount. I can get up to 3.95 or 4.05 volts, which is enough to charge a phone about 2/3 of the way. But after experimenting with a bunch of different charging solutions I determined that for a reasonable price, this is as good as we can do for now.

I worked out the electronics with the help of student testers over about 3 school years, but I never had a mechanical case I liked. In the past, I used upcycled food containers, and they were flimsy.

When I met with students this year in our “charger team” meetings, our first task was to design a sturdy case for the solar charger. We discovered you can collaborate in Tinkercad and it turned out to be a great solution! We all logged onto the same Zoom meeting, and then I created a Tinkercad project and clicked the Collaborate button to share it with everyone.

It’s amazing. You can all edit the same project at the same time. And with this group of kids, it turned out ok. We downloaded a couple of charging-port holders from Thingiverse and embedded them into a box, with some walls to hold the battery pack in place. The kids worked with rulers and measured battery packs and solar panels, and we updated the measurements in the file. Our first design had the voltage-in (micro USB) and voltage-out (USB-A) ports on opposite sides, with a flat lid.

This was iteration 1. The box took a really long time to print. I printed one at home, and showed them how it turned out at our next meeting. I asked the kids if we could make it a little smaller to save filament. So we moved both charging ports to the same side, and made the box exactly the same size as two solar panels side by side – and only slightly taller than the battery pack. I printed multiple copies of this version and then had a meetup with the kids to give them cases and electronics to try and build a solar charger. I parked at the school, and the kids pulled up with their parents where I handed off a bag of parts, soldering irons, and other tools.

A masked-up, hands-free supply exchange so we can do a makerspace project.

The students worked with iteration 2, and each one in the team built a charger.  I shared video instructions for creating the charger, and we had a zoom session that was a “learn-to-solder” lesson. The next time we met on zoom, they reported back that overall they liked the design, but the slots for the charging circuits needed a little re-designing. They wanted the slots overall wider, with a lip to hold the circuits in place. We made changes together in Tinkercad and then I printed iteration 3 for each student and did another round of supply-swapping. They built another round of chargers and tested them.

Charger Case 3D Print File

Here’s iteration 3! It turned out pretty well.

I started printing iteration 3 as fast as I could, and I distributed these to the kids so they could make this year’s final version of the solar chargers. I am really pleased with how they’re turning out. I’ve gotten a few back, and they’re sturdy and high quality and work pretty well!


I even had one student that designed his own case that had an angled top, better for collecting sunlight in the winter. He laser-cut it at home, and it’s awesome. I did not take a picture of it yet, but I’ll do that soon. Maybe that’ll be iteration 4 or a separate branch of solar charger cases.

This is an amazing, fulfilling project. We are going to be donating the solar chargers to Homeward Alliance right after Memorial Day, so they can be distributed to people experiencing homelessness who need them. We expect we will have over 20 chargers to donate. We will also put a link to a survey on the chargers so our “clients” can give us feedback on how well they held up. The students really loved feeling like they were making a difference and experiencing what engineering really is.

If you’re interested in making these, I have posted a YouTube video with assembly instructions, and I’ll also share the parts lists and .stl files here.



Parts List:

Case .stl file:

Lid .stl file:



How to make a Mini Wind Turbine from a Dollar Store Pinwheel

I’m teaching a Renewable Energy venture this quarter, and I wanted to make activities for the students involving wind, solar, and hydroelectric power. Purchasing mini-wind farm kits online is really expensive, so I experimented with making my own wind farm. After a few experiments I found a fairly easy way to make a wind turbine! Here’s how to do it.



  • Pinwheels from the Dollar Tree
  • DC Motors (preferably with a motor mount. We have THIS PACK that was sitting around school, so we repurposed them for our wind farm. The motor mounts work perfectly.)
  • Gears. I modified some gears found Here , changed the hole diameter and made an .svg file for laser cutting. Use this .svg file if you have access to a laser cutter. Otherwise you will need one large gear with a 7mm hole and one wee little gear with a 2mm hole.
  • Wire cutters, alligator clips, and a hot glue gun.


Step 1: Clip the end off the pinwheel hub with your wire cutters. You need to remove the pinwheel.


Step 2: Hot-glue the big gear to the pinwheel so it’s centered over the hole. Depending on the thickness of your material, consider hot-gluing the medium gear to the pinwheel and then the big gear to the medium gear. The medium gear will just be a spacer so the motor doesn’t rub against the pinwheel petals.


Step 3: Hot-glue the small gear to the shaft of your DC motor.


Step 4: Insert the motor into the motor mount and place the pinwheel on the hub with the gears facing in. Find the spot where the motor gear meshes with the pinwheel gears. Hot-glue the motor mount to the pinwheel shaft so it stays in place.

Step 5. The pinwheel now has nothing keeping it from falling off the hub, so what worked best for me was adding a TINY dot of hot glue to the end of the hub and then when that dried, add a little more and then a little more until I had a button of hot glue preventing the pinwheel from falling off. The pinwheel should still spin freely. If not, scrape off the hot glue and try again.


That’s it! I clipped a multimeter to my DC motor and was able to get 0.75 volts in a stiff breeze. If you chain several together in series, you can get enough voltage to charge a battery, perhaps. A little lubricant on the pinwheel hub seemed to help.

A student and I chained several together and ran around the parking lot with them. We got up to 5 volts. We clipped a USB charger to the circuit but it did not seem to be enough to charge a phone. For students, phone charging seems to be the gold standard of “is it a good circuit”, so that feels like a good goal. Stay tuned. Let me know if you are able to stitch together a wind-powered phone charger or you find something more efficient than these Dollar Tree pinwheels.




A class on engineering, electronics, and the Maker Mindset

At my school, rather than pass through grade levels, students have levels of autonomy – from “Explorers” who do mostly teacher-directed projects and products, to “Pathfinders” who do almost completely student-created projects and products, and job internships. I’m teaching an “Explorer” level class, so I’m introducing new learners to things they might not have known they would like but we’re asking them to try it. Other teachers with Explorer classes are doing things like creating pollinator boxes, producing a play, and studying floodplains. My venture project is called “Whimsical Inventions” and it’s a class about learning how to be a maker and a tinkerer. I began by presenting content about coding, electronics and circuitry, 3-D design, and doing research… but also teaching about the mindset of an inventor. Inventors solve problems, true, but inventors also make things because making things is joyful. We make stuff that is a little over-engineered because it makes us and others happy. We take everyday things and make them more beautiful, musical, entertaining, weird, or funny. If you’re making a thing to be happy, you’re more likely to take risks, to try something that might not work, to iterate on your design and make it better. This is the premise behind the class. To learn about coding, electronics, design, and engineering for the smiles.

As students finish with their final projects I am just feeling so blessed with the circumstances I got to teach in. The kids have come a long way with coding and Arduino. My makerspace is buzzing with 3-D printers and the laser cutter. Kids solder skillfully and safely. And they are doing a great job cleaning up and putting things away. I was lucky to get a class in which many kids were interested in the topic but many others just got placed there to try something new. My class is evenly split between boys and girls. It’s mixed-age with kids ranging from 6th grade to 10th grade. And I have gifted kids, kids with IEP’s, second-language learners, kids from all areas of town. It is just awesome. When I have a diverse group of learners I am a very happy teacher and this has been a phenomenal group.

And look at some of the fun stuff they’re making! One child is making a 3-D printed ferris wheel with a stepper motor and some LED’s. It’s coming along well! She downloaded the Ferris wheel design from Thingiverse.

Another student is making a motion-activated Moo machine. You know those cylinders that you tip upside down and it moos? He’s going to attach it to a servo and mount it in a stand with a motion sensor on it. When you walk by it will moo at you! Here’s the base beginning to print. He designed it himself!

A pair of students is making a light-up holder for your Instax photos. They’ve learned to solder and program these RGB LED strips and they’re going to mount some clips here to show off their photos. Another girl is using the same idea to make a light-up phone case. She has printed several iterations of the perfect phone case to make sparkly with the LED strips.

I have one pair of students that decided to make their own battery-powered car. They designed the car chassis themselves and soldered together the battery packs and switch and motors, and they’re doing to attach wheels and I’m just so excited to see how it turns out.

It’s just been fun. Part of our requirement for the project is that kids have to do a research project as well, and I’ve found that they really are engaged in their research which I didn’t expect. Early on in the class we did readings and watched videos on the value of tinkering and inventing useless things – we watched videos from Simone Giertz, Adam Savage, Ayah Bdeir and others. One of my favorites is this TED Talk from Steven Johnson which tells the story of how seemingly useless inventions can change the world. I’ve taught electronics classes before, but this is the first time I’ve really focused on teaching the mindset of an inventor, and I really think it has positively shaped the culture of the class. When I reflected on the times I learned the most and grew the most as a maker, those times tended to happen when I was making something I personally cared about but was just a fun side job, a useless invention. I hoped to give my students that same experience. I really believe most of them are, and it’s a very happy class to teach.

Sometimes when I’ve taught engineering classes before, the classes would end up being not very diverse (kids tend to sign up who already know they will like it, and I tended to have mostly boys in those classes), and I never felt like I had time to teach about maker culture. With a diverse class and making the culture/mindset front and center in the learning, it’s been a very fun experience and I can’t wait to show you how the exhibition products turn out.

Looking back and looking ahead to 2018

The start of a new calendar year is a traditional time of reflection and anticipation. I’ve been an inconsistent blogger this year, which wasn’t intentional, but if I had to clear some things off my plate, this was an easy sacrifice. It’s been a full year. Along with constantly learning and changing in my job, I have two daughters who are in 9th and 5th grade and a busy husband too. When my children were little, I thought to myself “It will be so nice when they’re older. They won’t need us as much!” While it’s true that we can leave the house without calling a babysitter now, it is NOT true that your kids need you less. They need you more! You need to be more present, for everything from driving to emotional support to helping them make sense of the world. It’s been a joy being with the girls as they grow into interesting, independent people – but it definitely keeps you moving.

The job has been interesting as well. I don’t always know what to expect next, but here are some highlights from 2017 and what I expect from 2018.

  1. The CS for All and #csk8 movement.
    “Coding” is gaining more traction in my suburban public school district, and this year for the first time we started some high level discussions on how to introduce computer science as a core subject for every learner. Several colleagues and I have been working on suggested paths for a K-12 computer science sequence.  We are looking for sites to pilot ideas over the next couple of years and investigating grants for professional development offered by Colorado’s Department of Education. It feels like a painfully slow process, but there is definite progress here and I’m excited to see where it goes.
  2. micro:bits.
    I started using these cute little devices in both my required 6th-grade class and in the elective upper-middle-school class. The younger kids learned cs concepts using the block-based MakeCode environment, and the older kids learned using the text-based Python environment. It’s such an interesting tradeoff. I didn’t feel that we covered as much material as I had in previous years, but I perceived that the kids were VERY engaged in their learning and took their learning in divergent paths. Introducing the micro:bits meant that some kids did not learn as much about coding structures such as variables and boolean expressions. But they learned more about the design cycle, and got really excited about testing and iteration. They generated questions themselves like “will it still work if I’m on the opposite side of the room? Will it work if I push the buttons at the same time? Will it work if I shake and push at the same time?” And then they answered their own questions and improved on their designs, on their own. I love the excitement. I want to keep that. And I also want the kids to be well prepared for high school work and to understand important concepts in computer programming, so having it both ways is hard!
  3. Virtual Reality.
    I have a nice gaming system with an Oculus Rift controller in my classroom, and we have a variety of VR devices in the media center. Kids have access to technology at school that they don’t necessarily have at home, and so it gives them something exciting to use at school that they are very curious about. I’ve integrated a VR unit in my upper-level CS class, and our building tech coordinator and I teach a quarterly enrichment class called VR Exploration. We work with the kids to make 3-D models in Blender and little exploration worlds in Unity. We’ve had a few students that have gone above and beyond with their work in VR and that’s been fun to see. Toward the end of this semester, we received a $5000 grant to expand our VR program and so now we’re faced with the question of: how do we grow the program? We have some thinking to do about how we make this a more inclusive and interesting and cross-disciplinary experience for kids.
  4. Engineering for Others.
    Our media specialist runs a pretty awesome after-school program called Engineering Brightness, and I love the premise of engineering with a purpose – to help others and to help students have empathy for the human experience. I’ve been working on the technical side of the program for quite some time and incorporated a lot of the engineering ideas into my Electronics elective, and this semester for the first time we were able to produce some finished products and send solar lights out to residents of Puerto Rico who were still living without electricity. It was a fantastic experience and I definitely hope to keep the project and improve on it this coming semester.Those are the main things cooking for 2018! What’s coming up for you?

Solar Lamps for Puerto Rico made by middle-schoolers

Earlier I posted about the Joule Thief lamps my electronics students made. Students soldered the circuit, designed enclosures and assembled the lamps. We made multiple copies of the best designs of the enclosures.

Joule Thief Project

The enclosures turned out really nice! We had a few different 3-D printed designs, and one really cute “upcycled” design made from household items.

After printing the enclosures and gathering materials, we had an assembly party in class. Students signed up for the design of their choice, and the student that created the design coached them through the assembly process. We signed cards, took pictures and put all of the lamps in a box. There are 27 of them!

I was able to make contact with person I follow on Twitter, Dr. Antonio Paris, who is busy delivering supplies to Puerto Rico for hurricane relief. A vast majority of the island still has no reliable electricity! Solar lamps are a key item that people need. I got his address and shipped the box out. You can reach Dr. Paris on his GoFundMe page.

We hope our little lamps are useful to anyone who needs a rechargeable light.

If you would like to participate in this process, I was able to gather all of the instructions in one place in this Google Doc.


Please reach out to me or find the Engineering Brightness project at: if you would like to get your students involved in learning about circuitry and engineering for social good. 🙂