Electronics Challenges

This week we had a soldering project and Tinkercad assignment to complete.

Soldering Practice

Assignment: Continue practicing soldering this week. You may solder together the wires in your Light Up! Challenge or continue soldering onto PCB boards. Work for about 1 hour and document your progress on your website. What are some of your take-aways? How have you grown and improved your skills in the time.

Response: I actually finished the soldering project shortly after class ended. Since I've got a fair amount of soldering experience, I was able to move pretty quickly through the activity. My board isn't perfect, but I wanted to challenge myself to get it done quickly and efficiently. This was the first time I've soldered since eye surgery, and to be honest I wasn't sure I'd be able to do it.

About three years ago I started to develop posterior subcapsular cataracts. It's a fairly rare condition, especially in someone my age. These kinds of cataracts develop quickly and block light from reaching the retina. In a matter of months, I was nearly blind in one eye and my other eye was getting blurry. My doctor said that I had the worst cataracts he'd ever seen in someone my age. Go me!

The last time I soldered it was to teach a class at the library. I had to call in an experienced volunteer to help, because I was struggling so much to see that I knew it'd be unsafe for me to use the soldering iron. At the time I felt so upset and broken because I couldn't do something that was once so easy for me. Luckily After two surgeries, a laser procedure, and a ridiculously complicated eyeglasses prescription I can see again.

So my big take-away was simply that I could do it! But in the greater context for me, it really made me think about accessibility. It made me think about ways I can share projects with folks who may struggle due to physical limitations. And it made me consider how many others, especially the seniors who visit our library often, may miss activities they can no longer enjoy easily or safely. I wonder how I might find ways to simulate or edit activities -- like electronics, woodworking, etc. -- for others that are limited due to disability.

Anyway, this was a really fun project. I really liked the way the microphone is used as an input for a visual display. The flow of light as it moves across the LEDs is very pretty. As an educator, this would be great for more experienced students, because they need to determine read a schematic, use a color guide to select resistors, and ensure the right capacitors are used in the correct place. It also adds a good challenge soldering the chip without bridging any of the connections.

TinkerCAD Circuits Practice

Assignment: TinkerCAD circuits is a place where students can plan and simulate circuits they want to build for their solution. Take 30 mins this week to explore more about TinkerCAD circuits. Post pictures and explanations of your thoughts through the process. What were the roadblocks that you can expect students to run into? How did you work through these? How might you guide your students through the roadblock to build the "playful" and "failure forward" (Martin, p.35) elements of Maker Mindset when using this tool? How might you have students use the notes tool to show their thinking before going to build? What are you interested in learning more about?

Response: Since I've worked with Tinkercad circuits before, I was able to finish the sample project in class. (Below.) I really like the idea of modeling or prototyping with Tinkercad with students before moving to physical components. Aside from the fact that it can be really useful in virtual environments, it gives students an easy way to add notes and label components. I think we often forget to encourage that type of documentation with our students and I think it's important. I also think it's a great opportunity to have students think through how the electricity flows through a circuit or to go from a schematic to breadboard safely, where if they make a mistake you don't need to worry about shorts, overheating, or other mishaps.

One feature I had previously missed (or perhaps it's new?) was the ability to download a schematic for anything you build in Tinkercad circuits. That's a great feature! As a teacher, I could build a sample circuit, give students the schematic and then have them work to recreate it with components in Tinkercad. If also make it possible to really prototype virtually and have a format that is easy to share with others. Below I show the completed 555 circuit and the schematic generated by Tinkercad.

Going further: But since this is a design challenge, I thought I'd push Tinkercad to see how far it could go. Conveniently, the Make: Newsletter arrived in my email with a book excerpt from Make: Electronics by Charles Platt. I love his work and have previous editions of this book for teaching many times, so of course, I had to check it out. The sample project was a for an Intruder Alarm System using Raspberry Pi. However, he also included instructions for building a circuit using 555 chips to make the alarm. Since Tinkercad doesn't have a Raspberry Pi component yet, I decided to build the 555 version.

As I worked through recreating the circuit I realized that Tinkercad does have some limitations. For example, you can't resize components. That meant that sometimes I needed to put components to the side and connect them to the breadboard with wires, which is obviously not how I'd do it in real life. Also, because many of the larger components are more 2D than 3D (so that you can see them) you really have to plan the order in which you add components, because some may end up hidden. You may notice this with the various capacitors in the diagram below. You also can't choose specific types of certain components. For example, the project called for a 1N4148 fast-switching diode, but Tinkercad doesn't allow you to choose a type. When replicating someone else's project this can make it difficult to prototype accurately. I also found that the simulated resistors seem to work a little differently that expected. With the combination used I should have had a 3-second delay once the alarm is turned on. But my circuit's delay was much faster than that. Luckily, it's easy in Tinkercad to change the resistors to adjust the delay as desired. It also seems the capacitors in Tinkercad are assumed to be charged completely at the start of the simulation, which affected the switching in this project.

Unfortunately, my replicated project doesn't quite work correctly. No matter what I do The alarm sounds at the start and will not stop. As far as I can tell this is because the capacitors start as powered, essentially circumventing the cascade of signals to set the alarm. I can't find a way to change that.

That said, this was a great way to really explore the circuit and understand how it works without pulling out any physical supplies. I think that would really be useful for older or more experienced students that way to try circuits with materials I may not have on hand in the makerspace. It's also fun to replicate projects from books and magazines to better understand how they work, before committing to buying components or taking the time to physically build the item.

Below you can see the original design presented in the book as compared to my design. Unfortunately, when you use the "Send to" feature in Tinkercad to save a PNG of your design, the notes are not included! I had to do a screen capture instead. You can try the circuit yourself here.