Arduino Logic Gates Part 2

I'm happy to report that I was successful in my second attempt to get the Universal Logic Gate Arduino system running and working. The problem came from a mistake in the design diagram:

I discovered the white cable was placed in the wrong slot in the design and it actually needed to be in slot 8, which I was able to discover by taking a close look at the code.

Once these changes were made, I was able to experiment with complex boolean expressions. Below shows A AND (B OR 1) simplified to A

And here you can see NOT (NOT A AND NOT B) simplified as A OR B:

It was really ratifying to get this working, especially as it involved my analysis and correction of an error in the design document.

Arduino Logic Gates

I want to use the Arduino to build examples of logic gates in the hope I can create a Arduino project that can have multiple inputs to demonstrate complex logic circuits and help demonstrate the simplification of complex boolean algebra statements.

I looked for help online and found useful, but basic circuit diagrams and Arduino code on instructables.com.

The project that appealed the most was a universal logic gates implementer, with 3 input buttons and mulitple where complex logic circuits could be entered and tested.

The design appeared quite straight forward:

I applied this to my Arduino, but it would not work:

My main problem was I didn't really understand what the circuit was doing, so I decided to go back to basics and create a simple NOT circuit which worked and I was able to manipulate the code:

I then got more ambitious and attempted to use 2 inputs and create AND and NOT gates based on the following diagram:

At first this didn't work at all:

Again, my inexperience left me unsure why. With the NOT gate, it didn't work so well at first because the LED was plugged in the wrong way, but this wasn't the case with this circuit. So, I built it again, using the opposite side of the breadboard. Amazingly, this worked, below is the OR gate working.

And below is the code for and AND gate

Which can be seen working below:

My make Part 1: what's a resistor

I have now started investigating my own Make. I decided to buy an Arduino Starter kit from Elegoo . The reason for this is because the area of difficulty I have most with my subject is teaching the simplification of Boolean Algebra expressions. After my first make involving circuit boards, I am interested in seeing if I can create a simplify complex circuits using the Arduino and breadboard to help both my knowledge and the knowledge of my students.

I am going to go through the instruction manual, project by project. But the first thing I have learnt is what a resistor does, which I never knew before.

Basically, resistors come in many sizes of Ohm, from 1 to 1 megaOhm (roughly a million Ohms). I did a series of experiments using different resistors to power a red LED to show the lower the Ohm resistance in the resistor, the brighter the light will be:

Here I'm using very low resistance and the light is very bright.

But in this photo, I am using a resistor with more resistance and the light is not as bright.

Without the resistor, the power going to the LED would probably burn out the LED and destroy it.

After this I experimented with a RGB LED, which can generate any light colour. To do this I had to program the Arduino to change the shades of red, blue and green lights:

Initial impressions: The breadboard is very fiddly to use and it can be difficult to get the pins into it. My eyesight also struggles with the small writing and holes and I think I will need to use a bright lamp to see everything more clearly.

Session 3 - Task 1

The three main questions framing the day were:

What are the strengths / the benefits of using Making as a pedagogical tool?
What are the weaknesses / the limitations of using Making?
Are there topics which cannot (or ought not) be addressed through a Making pedagogy?

We were first introduced to the concept of polyrhythms and the ratios required to make them. After this, we split into 2 groups for different activities. In my group, we did an eTextiles activity to create a bag with flashing poly-rhythmic lights which used a version of the Arduino Lilypad.

After examining a pre-made model, we cut material from a pair of old trousers.

We then sewed conductive thread in the material to allow a circuit to be made in the textile.

It looked like this after the conductive thread was added:

Whilst Salma and I were doing this, the other pair in our group were programming the polyrhythm algorithm for the lights to blink and testing it worked on a paper based example:

Then we hit a tricky spot, hand stitching the LED lights onto the bad using conductive thread.

The conductive thread would fray extremely easily, making it nigh on impossible to thread through the needle we used. Everyone got frustrated, but David persevered and created a working bad with 2, rather than 4, lights which flashed polyrhythmically. 

So, lets answer the original questions:
What are the strengths / the benefits of using Making as a pedagogical tool?  Well, the bag was quite impressive when completed and would naturally lead to the requirement of not just how you made it, but also why the lights blink in the order they blink in. This takes learning away from simply doing and internalising, to doing, internalising and then explaining, which is quite a leap.

What are the weaknesses / the limitations of using Making? That bloody conductive thread! I lost patience, so I imagine students would to. Huge amount of preparation would be needed too, but the bag looked great. We estimated you would need at least 8 hours or 1 whole term to complete this project with a class.

Are there topics which cannot (or ought not) be addressed through a Making pedagogy? We looked predominantly at Maths as a theme, introducting textiles, computer science, design technology and a bit of physics, which isn't bad for one task.

Session 2b: Access, Equity and Engagement in Making

This was a theoretical session where we explored notions of equitable engagement in Maker spaces. We had been given a pre-session reading, I had read "Making Sense of Making: Defining Learning Practices in MAKE Magazine" by Brahms and Crowley (2016). The text focused on the community of self-appointed "makers" who read and contribute the the making community whose pivot is MAKE magazine.

The paper focused on one particular making project, made by a father and son team, who created a rocket ship tree-house that had numerous technological features. Focusing on this make allowed the authors' the ability to demonstrate the inequity seen in making; that it is the pursuit of white, middle-aged and incomed men who are higher educated.

As a group, we discussed the paper and recorded out findings in a mind map, which can be seen below:

I think out discussion generated two important considerations which could not be found in the paper. The first involved ability or disablity and the lack of entry, profile and consideration for disabled makers within the maker community. 

The second consideration we had was who are the makers? I brought up the idea of model boat makers I see regularly at the boating lake in Victoria Park, all of who are clearly white and middle-aged. But is there form of making accepted as making within the MAKE magazine community. This ideas was paralleled with the Women's Institute, who are not male but middle aged and probably middle incomed and would make things on a regular basis such as craft, textiles, food and horticulture. Are they not makers too? Making parallels with different groups enabled us to identify the importance and drawbacks of clubs and the exclusive nature of clubs. Yet the values are shared, but the name, MAKER, excludes.

After this, we had another practical activity involving programming. We were split into 2 groups, one group would tackle an activity to reproduce sound using the Scratch visual programming environment, the other group used the physical programming language Code Jumper which has been developed by Microsoft for the visually impaired. This was particularly relevant for me, as I teach computer science and I also have had students how have no visibility, who have had to have alternative lessons when the classes use Scratch in Year 7 due to its exclusive visual nature. This always makes me feel bad.

As an experienced user of Scratch, I was able to complete the tasks quickly and spent most of our half of the session helping colleagues in my group. Here are some photos of our solutions:

We then moved to Code Jumper, which I found initially very confusing, but the use of iteration and sequence became quickly apparent:

We required a lot of guidance, but were eventually able to understand how the blocks fitted together. Sadly, I think creating the same programs in Scratch in advance of this activity prevented us from getting the full experience of creating programs without seeing code, as we had seen solutions in Scratch.

Session 2a: My first make

In this session the group were given a tour of the maker lab and the safety rules were explained. We than began our first make: a not gate in a logic circuit:

In the following photo you can see our work space and the tools we had to complete this make:

Tools: 

- Step by step instructions, printed in colour with photos of completed not gate and extension activities.

- Glue gun and glue

- foam/card + craft knife

- Soldering iron and solder

- copper wire

- clippers

- lots of wires with crocodile clips

- battery pack

- various components, such as led lights and switches.

We began the make, carving out a not gate symbol from foam then attaching a blue switch box using the glue gun:

We then used copper wire and soldered this to the blue switch box in to make the electric circuit and the not gate:

Once that was completed we could attach the cables to switches, battery packs and LED light to test the circuit, which worked:

I was asked for my thoughts on the activity, which I will summarise below:

- I have worked with logic circuits a lot while teaching computer science, so I understood how a not gate works and what to expect as the outcome.

- However, I had not created a circuit before, so I found the introduction of the electric circuit confusing.

- But I really enjoyed the make, it made me think far more about how logic circuits work, before this I found basic logic circuits fairly straight forward to teach and learn, this made me consider the physical and real application of logic circuits.

As we had finished the task early, we began the extension activity, which was to create an AND gate. This was not as successful, and after completion, the LED light would not light up:

We needed help to solve this problem, which was a poorly soldered connection in one of the switch boxes (see below):

After this, it worked.

It was quite frustrating when it didn't work, and I imagine this is something which would be amplified with students, who can give up and become defeatist quickly, especially if they don't believe in their own ability and are doing a task/subject they are not comfortable with.

But it was great when it did work an we realised we were victims of some dodgy soldering.

Session 1: A Table for Mice

In my first STEM Maker session, I had to make something to help introduce myself. Below you can see two images of my creation:

I hope the illustration below guides your imagination to the possibilities of this table:

There was little thought into why I constructed a table for mice, other than I didn't want to just create my name. I had also been teaching Big O notation to my year 13 computer science class, so perhaps the table design was inspired by this. It also gave me the opportunity to shoehorn some important information about who I am and what I teach.