Archive | May 2020

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:



Emergency Online Teaching – My Experience

I have not blogged in a while, and it’s hard to be reflective about your own work when you’re in the moment and so unsure WHAT you’re even doing, so you can’t pause to think about why or how. But now that I’ve finished my last day of teaching online content, I think it’s time to look back on what worked and what didn’t – because chances are, we’ll be doing this again before the coronavirus pandemic is over.

I live in Colorado, and as we watched the pandemic unfold on both coasts, we knew by early March that things were going to change for us drastically. We left for spring break on March 13th right after having a big open-house exhibition at my school, and after I attended my own daughters’ spring concerts and celebrations. When we left for spring break, we knew we weren’t coming back. Although our district had only planned for a 2-week break at the time, the writing was on the wall that we’d be out all quarter. We started to plan for it.

Our administrative team did a wonderful job creating a remote-learning plan that was flexible and could accommodate as many kids as possible.

  • We did some test-runs with Zoom before spring break started, so teachers and students were familiar with the platform. We created a set of school norms for using Zoom and trained all of the students on these norms. Most teachers were able to run a class or two on Zoom, just as a trial, with kids spread out around the building and teachers conducting class from our office. We continued using Zoom for the duration of remote learning although we were aware of concerns with privacy. It really is a superior platform for online learning, and for a quarter, we decided to make the tradeoff.
  • We extended our spring break an additional week, to give ourselves time to check computers out to students and write lesson plans. Students came to school early the week of March 23 to pick up their technology.
  • We used Google Classroom as a central point for all remote learning. We agreed to use a standard structure, where assignments were labeled by day and week, and all assignments could be done asynchronously – with short video lessons where needed.
  • We posted all assignments on Sunday evenings, with due dates a week later. (I found myself breaking from this slightly, however, posting Monday/Tuesday assignments on Sunday night and Thursday/Friday assignments on Wednesday).
  • We agreed to hold online, live Zoom sessions twice a week for each class. Intensive classes (the core subjects) were held Monday/Friday, Venture classes (our project-based blocks) were held Tuesday/Thursday, and Wednesday was reserved for Advisory and staff meetings. We agreed the live sessions would not be required, but would be set up to provide support or teach the content live that was already accessible in the online videos.
  • We kept a checklist of all of our students, so teachers could log which students were attending class and/or turning in work. The checklist was used to follow up with kids we didn’t hear from. The checklist was just a normal Google sheet that looked like an attendance roster, and next to each name there are checkboxes to log if we had seen/heard from the student. Through the checklist, we kept track of families dealing with Covid, families that needed food assistance, and some families that other obstacles to attending school – working, taking care of siblings, or lacking any internet except a phone data plan.


This is what my Google Classroom looked like, and every teacher in our school uses the same setup.

Zoom links are always posted at the top of the page. As you scroll down, weeks are in reverse-chronological order and all assignments are grouped under the week in which they were assigned. The consistency was helpful to everyone and I am so glad our admin just set the structure up for us.

I teach Algebra/Geometry (Integrated math, sort of), and had planned to teach quadratic functions, systems of equations, and data analysis. I had gotten a week into teaching quadratic functions when the semester ended, and I know my students that wanted to move on to Algebra II next year would need to know these topics. So I had to do the best I could teaching new content in this format. For each lesson, I made a video which I posted to YouTube, created some structured notes that went with the video, and then curated some Khan Academy exercises for practice. I assigned 1-3 practice sets for each lesson, so it wasn’t an overwhelming amount of work. If we had been in the classroom, the structured notes would have been set up as group activities – I just adapted them to be individual notes instead.

I think a huge part of the value of the video is for the students to connect with me by hearing my voice and seeing my face, so the videos are probably not as meaningful for you. I know there are tons of videos out there that teach the exact same content I’m teaching – but I made these anyway, because I believe there’s value in the students hearing directly from me and knowing I care and believe in them. You can use them if you like, but I really do think your students benefit from videos you make yourself too.

Quadratic Functions Playlist

Systems of Equations Playlist

Statistics Playlist

Each day, I asked the students to do the Khan Academy exercises, mark the assignment as “done” in Google Classroom, and write a short reflection on how it went. For the units on Quadratics and Systems, I included a small end-of-unit assessment. For the Quadratics unit, it was a packet of problems I curated from an SAT test prep book. For the Systems unit, I assigned the students a computer programming project as an assessment.

Our grading system is a competency-based system, with marks of “Not yet”, “Basic Understanding”, and “Exemplary Understanding” for content. There really is not a good and fair way to check students’ competency levels in this kind of system. So if a student did most of the assignments and put in a solid effort on the assessment with reasoning I could understand, I gave him or her a mark of “Basic Understanding”. A few standout students received marks of Exemplary Understanding, but I reserved this for when I could tell it was really warranted. When in doubt, I used the “Basic” mark. If students did not participate at all and did not do assignments, I left the grade blank as if they didn’t take the class. They’ll get a chance to learn it in the future when learning is purposeful and planned, not emergency.

So that’s what I decided to do. Here are my reflections on how it went.

From my perspective – I felt like this was a decent first attempt at online teaching. I actually do like Khan Academy as a resource for practice problems. The students can get feedback right away, they can use the hints and videos, and I could screen-share with students during my office hours to help them with the practice. It was super useful. I probably will use Khan’s exercise sets next year when we have to go remote again. A little more than half of my students completed work regularly. About a third showed up consistently to our synchronous Zoom sessions. I enjoyed the online zoom sessions, and after I got about a month into the schedule, I really liked it. I did do some repetitive work – creating the videos and resources for the lesson, and then teaching the exact same lesson live twice, then teaching it again during office hours – but my days were so much more flexible and easy to manage. I had to carve out a couple of hours for online classes each day and then I could finish the rest of the work on my own time. At 3pm or 2am or whenever it was a good time for me. By the time May rolled around, I was very comfortable managing my time this way, taking care of my house and family and balancing the school needs. And really, I’m far less stressed right now than I usually am in May. MUCH less stressed. I’m kind of thriving on this flexible online schedule. I get outside a little every day, tinker and create, play with the pets, make a variety of food, and enjoy spending time with my husband and kids. I was really sad and stressed when the quarter started, but now that it’s mid-May I’m doing pretty well.

From the kids’ perspective, it’s more complicated. I gave an end-of-year survey to my students today and was surprised at some of the results. The first question was about student motivation levels. Less than half of my students responded to the survey, so the results may yet change if I get more.

The bars correspond to these prompts:

Students could check multiple boxes. The most popular answer was: “I didn’t try as hard as I could have”. Second most popular was a three-way tie: I was motivated because I really enjoy math, I was motivated because I’m used to trying hard in school, and I tried my best every day. It seems, though, a majority of students are disappointed in their effort.


I asked students what they thought of Khan Academy as a practice tool. This surprised me.

1 corresponds with “It’s terrible, please don’t use it anymore” and 5 corresponds with “It’s a good way to practice and you should use it next year too”. Generally students are OK with Khan as a practice tool. They don’t love it but don’t hate it. Some helpful comments included “It’s good for practice, but I don’t learn new content well from it”, “I like that I know right away if I got it right and can get help if not”, and “It was only a few questions so it wasn’t overwhelming.”


I asked the students how they felt about the feedback they got during online learning, with 1 being “Not Nearly Enough Feedback” and 5 being “I am satisfied with the feedback I got”.

I almost did a spit-take because I got REALLY behind on grading – not just summative assessments and comments, but the daily work of doing into Google Classroom and just checking off assignments and writing “Good job”. I certainly didn’t give them this feedback, unless they asked for it in office hours or zoom sessions. Strange perception. I expected them to rake me over the coals and hold me accountable for getting behind on feedback. I don’t know why they didn’t. Maybe because they practiced on Khan they knew what progress they were making? Maybe because I sent emails reminding them about stuff?


I asked students if they felt ready to move on to the next math class. This graph also surprised me.

A vast majority of the students wants some review and some new stuff next year. Huh. I would say the kids in the “I feel like I mastered it” category are also the ones I would have pegged as fully ready to move on, but some of the other kids in the 86% are ready but don’t perceive themselves as ready.


I asked students what topics they’re interested in learning more about when it comes to math. This is what they said.

Some of the labels disappeared so this is a list of the choices.

The most popular answers were: Puzzles and Logic, Computer Programming, Physics and Mechanics, Data Analysis and Statistics, Finance and Spreadsheets, and Measurement/Design/Engineering/Construction. The least popular were: Advanced Functions/Polynomials/Calculus, Probability, Solving more and more difficult equations, and careers that use math.

I brought this question up just in case standardized testing gets postponed, cancelled, or has a lower priority placed on it, maybe freeing up a little more math time for the things kids would like to learn. We do SO much with functions in high school math. It’s a bit much, in my opinion, when there’s so much math out there that kids like.

I asked one final question which was: If math is online again next year, what do you think you need to be successful? The responses were all over the map, some hopeful, some disappointed. They’re important to read. There are a lot of kids beating themselves up for not feeling more motivated and I think they’re being a little hard on themselves, considering.

So there it is, my first emergency-remote-learning quarter of Algebra in the bag. Lots to think about as we head into next fall and have to continue keeping kids safe and somehow figuring out how to help them learn.

How did it go for you? What would you do differently and what did you like about your system?