building the logo turtle

Seymour Papert started lots of things!

“How to build a programmable floor turtle” is on Josh Burker’s (JoshB) site: LogoTurtle

INSPIRATION

Going back roughly 50 years, the inspiration originally came from Seymour Papert’s Logo floor turtle which accompanied the Logo programming language, developed for children.

I was further inspired on reading Neil Gershenfeld’s account in his book, Designing Reality, of a conversation he had with Seymour, back then:

“As fab labs started doubling and the Fab Academy began to grow, Seymour came by to see me to talk about them. I had considered the whole fab-lab thing to be an historical accident, but he made a gesture of poking his side. He said that it had been a thorn in his side that kids could program the motion of the turtle but could not make the turtle itself. This had been his goal all along”
Designing Reality, p. 29

Another goal I have is learning more electronics in a practical way. So, I was on the look out for a meaningful project to help me achieve that.

These factors pushed me over the edge. I decided to build the Logo Turtle!

Following the links in JoshB’s article I bought the materials from adafruit, Core Electronics and some other online and local stores.

There were some mishaps along the way. eg. it’s much better if you can get the 2xAA battery holders with a hole in the middle for the flat head screws. After some searching I found an Adelaide store, Altronics, which had these.

I wrote to Josh and his advice was that I should make a Printed Circuit Board (PCB) since the breadboard approach produced unreliable results. He sent me the Gerber files that I needed for that.

I downloaded a free open source viewer, Gerbv to view the files.

I asked for advice on the Adelaide Maker Space forum about how to get the PCB made and some helpful people suggested a couple of companies. I went with PCBWay and they made the PCB for me.

I have my own 3D printer so I printed the parts in PETG. All the links for that are in the JoshB article.

HELP

I’m an electronics novice so I had trouble finding some of the equivalents between the breadboard design and the PCB design. Fortunately I found Tony Onofrio, a friend in the Adelaide Hackerspace group. He translated the fritzing diagram on JoshB’s article into a PCB diagram for me.

Unfortunately, the link to the LogoTurtle software on JoshB’s article is broken. But I wrote to Josh and he sent me the files. Following his instructions (downloading drivers and Java) I tested the LogoTurtle software on the metro mini board and this was successful.

The software is a Logo implementation in Java. The logo files are text files which you download to the metro board. I didn't understand how it was working but spoke to David, a Java programmer at the Hackerspace group and he explained some of it to me.

The next step was soldering the parts onto the PCB board. This was hard for me since I’m a novice at soldering. Again Tony helped out by giving me some lessons in soldering. The order in which I soldered the parts on was: (1) resistors x 2 (2) Darlington driver, note the notch (3) Metro Mini (4) header pins 2 x 5 then x 3 (5) photocell (6) switch

Having done all this I was ready to attach the PCB to the turtle. I soldered the 4 battery leads, plugged in the stepper motor 5 pin connectors and inserted the 4xAA batteries.

I found some pens with the correct diameter at Office Works and placed one in the pen holder on a sheet of paper. I flicked the switch to turn on the metro power, indicated by a green light and pressed the reset button

Hallelujah, the turtle drew a square! Logo.jar runs the test.txt file by default.

to startup
square
end

to square
pd
wait 1000
repeat 4 [fd 100 rt 90]
pu
alloff
end

But note the angles are not quite 90 degrees. Using trial and error, I changed the angle to 85 degrees and it drew a pretty good square

JoshB’s solution here is to add a shim to alter the angle of the stepper motors reproduce. I tried this but it didn’t make any difference.

I wrote to JoshB again and he suggested I alter the sys.txt file where the logo drawing procedures are stored as text files.

So I altered the rt and lt turn procedures by multiply and angle by 85/90. This then drew a perfect square.

to rt :n
make "n :n * 235 / 100 # (the multiplying factor was altered from * 25 / 10)
repeat :n [rstep- lstep+]
alloff
end

I then tried a pentagon, square and triangle combined:

The more ambitious rotating octagon worked well first up:

Then I made a similar change to the arcrt (arc right) and arclt (arc left) procedures and then I could draw near perfect circles and arcs.

An interesting feature of the design is the photo resistor. When exposed to the light the resistance goes down. This photocell is plugged into A0 on the Metro Mini, so you can introduce this value into the code to achieve variations based on light intensity.

Following JoshB's notes I established the A0 values for a bright flashlight were roughly 960, for normal light 830 and with curtains drawn about 565. So I ran the following procedure in normal mode and flashlight mode which modified the size of a circle:

to startup
wait 1000
let [n a0 / 10]
repeat 10 [
arcrt 50 :n
make "n a0 / 10
]
alloff
end

So far, so good. I could draw closed shapes with the LogoTurtle.

But to draw people's initials, for example, you need to be able to lift the pen (logo command pu) and put it down again (pd) at the right times. This requires fitting a servo to lift the pen. I also added a weight to the pen to ensure it drew firmly on the paper when down.

Here are a couple of initials I drew, using the alphabet file from JoshB's LogoTurtle Curriculum. I presented these to a couple of members of the Hackerspace group who have been helping me:

REFERENCE

Josh Burker's original article: LogoTurtle
LogoTurtle Curriculum (lots of great ideas here)

Fab Labs haven't been growing exponentially

The Gershenfelds make the claim that Fab Labs are growing exponentially every 18 months in their 2017 book, Designing Reality (p 11 and pp 100-102) and follow up articles (Digital Fabrication and the Future of Work, 2018)

They actually claim that this new growth is a continuation of Moore’s Law and this fuels their “third digital revolution” rhetoric (book, p.102)

I wish this was true but it’s not.

This rose coloured glasses rhetoric has puzzled me. There remain significant barriers to setting up and maintaining a Fab Lab. The Gershenfelds point out themselves that training Fab Academy alumni to the daunting skill level required follows linear growth.

Here are the figures from their 2018 article:

In this article they speculate that there will be 25,000 Fab Labs by 2026

The Gershenfelds then predict that Fab Lab growth will level off because by 2026 the machines will be so cheap and improved that personal fabrication will replace Fab Labs

The 25,000 Fab Labs prediction corresponds very roughly to 4 doublings over the 10 year period, 2016-2026, ie a doubling every 2.5 years, not 18 months:

(1,300 2,600 5,200 10,400 20,800
or 1300 * 2^4 = 20,800

However, if we go to the Fab Foundation home page, the figure cited there for the number of Fab Labs currently in the world (December 2024) is 2300 +

So the doubling time since 2016 has been 8 years, not 18 months or 2.5 years! Also, as I pointed out in my earlier article, fab transformation hurdles, Fab Lab / Maker Space growth in Australia has stalled

There are plenty of reasons identified in the Gershenfelds book about why Fab Labs haven’t continued to grow exponentially. I think their book contains plenty of realism as well as hype.

But they still maintain their highly optimistic exponential growth rhetoric about digital fabrication. The most recent writing I have found by the three brothers is in 2021 on the "Centre for Bits and Atoms" site, where they say:

Digital fabrication today is at approximately the same stage that digital computation was in the early 1980s, when personal computers gave millions of people access to a capability that had previously been limited to large organizations. PCs were to be followed two decades later by billions of mobile devices and trillions of connected things.

Today we have thousands of fab labs, with the potential for making millions of personal fabricators — small-scale fabrication systems for individual use — and a research road map leading to a future with billions of universal assemblers, and then trillions of self-assembling systems in future decades. As with the exponential improvements of the earlier digital technologies, each of these stages of development promises to be faster, better, and cheaper.
- The Promise of Self-Sufficient Production

In all our arguments and discussions we need to avoid the hype cycle rhetoric.

Nevertheless, community Fab Labs and school based Fab Learn Labs are still great things with enormous potential IMHO. I have outlined some of the reasons why in my earlier article fab transformation hurdles

As the authors say in their original book digital fabrication is both hard and rewarding. This quote sums it up:

"Digital fabrication is hard. It introduces a set of new competencies, including the navigation of continually evolving CAD and CAM software as well as additive and subtractive hardware, embedded computing, and an understanding of the biological and chemical properties of the materials used in fabrication. It also requires design thinking, creativity, collaboration, problem solving and resiliency. These all require knowledge, skills and mindsets that cross very different disciplines and domains and, as a result, are not currently well integrated. We define fab literacy as the social and technical competencies necessary for leveraging digital fabrication technologies to accomplish personally and professional meaningful goals, as well as a commitment to the responsible use of the technologies. We cannot build towards a more self sufficient, interconnected, and sustainable society without widespread fab literacy." (p. 64)

Update 26/12/24:

I sent this to Neil Gershenfeld and he was good enough to respond, as follows:

But at FAB24:

https://fab24.fabevent.org/

I spoke about two reasons why counting labs was no longer relevant:

• With the proliferation of mini-labs, superlabs, biolabs, fab hubs, ..., a single number no longer applies
• What matters at this stage is counting the impacts of the programs that have matured -- student outcomes, fab city metrics, businesses incubated, ...

fab transformation hurdles

Background reading: Designing Reality: How to Survive and Thrive in the Third Digital Revolution by Neil Gershenfeld, Alan Gershenfeld and Joel Cutcher-Gershenfeld.

Some write their stories in words. Some write their stories in code; some with materials; some with machines. My current story is a wobbly exploration through all these media to understand the Fab Lab.

Neil Gershenfeld has articulated his Fab Lab vision now for 2 decades: “How to make (almost) anything”. After a brief revisit of what a Fab Lab is this article outlines some of the hurdles that have to be overcome to achieve that vision.

The Gershenfeld interview with Lex Fridman was fascinating IMO

Digital computation has led to the smart phone. Digital communication has led to the Internet. These first two digital revolutions have created new jobs and transformed traditional jobs. Will digital fabrication continue this trend. Is it correct to claim, as the Gershenfelds do, that digital fabrication is the third digital revolution? See Footnote.

What is a fab lab? Digital fabrication is often misunderstood in that people think of it as being just 3D printing. It actually involves a wide range of additive and subtractive technologies, as well as computer-aided design and embedded electronics

The five types of machines found in a conventional fab lab are:

• Vinyl cutter
• Laser cutter
• 3D printer
• CNC machines
• Digital Embroidery machines

The MIT course that Neil Gershenfeld initiated in 2003 named “How to make (almost) anything” was a huge hit which led to the creation of Fab Labs around the world. An inspirational slogan!

What sort of things can we make? Well in theory the list goes food, furniture, and crafts to computers, houses, and cars.

What is the overall goal here? The short term killer app is personal fabrication, the ability to make or modify what you can't or can buy in a store. Personal fabrication can take many forms since it depends on each person. My 3D printed personal favourite so far is the Sierpinski Pyramid Lamp.

One possible social goal is to transform consumers into producers. The Gershenfelds approve the Blair Evans vision:

A potential vision for this new blend is represented in the inspiring work of Blair Evans, an accomplished automo­tive engineer and educational leader who is now developing a local ecosystem of fab labs in an economically distressed part of Detroit. His vision is about what he calls “thirds”— building out the digital fabrication capability to the point that people might spend one-third of their time in paid labor to buy what they can’t make, one-third of their time using digital fabrication facilities to make what they can (with a focus on furniture, housing, aquaponic food pro­duction, and other practical things), and one-third of their time to follow their passions in whatever way they choose
- Digital Fabrication and the Future of Work

However, in practice, what you can presently make depends on whether your local Fab Lab has million dollar machines or thousand dollar machines. In practice many fab labs can make very cool small things (eg. an articulated dragon on a 3D printer) but are not making big things. To make the bigger things you would need the big machines, like a CNC milling machine. Yes, the price will drop and access will improve over time. But for now it depends on where you live.

Not every Fab Lab or project ends in success. Neil’s brothers, Alan and Joel Cutcher-Gershenfeld sometimes play the devils advocate in their book. When things don’t turn out the inspirational slogan “How to make (almost) anything” transforms into “How to (almost) make anything”

A case in point. I tried for 3 years to initiate a Fab Lab in Alice Springs. See my 2021 article Your town needs a community Fab Lab

I lobbied government, industry leaders, education leaders and citizens there. But to no avail. My calls were sometimes not returned and in the instances where interest was initially shown it never led anywhere significant.

I did have more success in introducing new innovative subjects and 3D printer technology at the school where I taught. The admin could see the need for a more engaging STEM or STEAM curriculum. But at no stage was I offered the opportunity to explain Neil Gershenfeld’s full Bits to Atoms vision. It felt like being at a banquet but only allowed to eat the grapes.

My failure to kick start a community Fab Lab in Alice Springs could be put down to my poor persuasive powers. However, it might also have been due to deficiencies of the local ecosystem, a troubled town of 25,000 people, to nurture innovation. Neil Gershenfeld points out that MIT isn’t an isolated technology park but is embedded in an ecosystem or environment “that mixes long-term research, short-term development, small start-ups and large corporation, along with cafes, clubs and parks” (p.49)

Furthermore, I notice that Fab Labs are not growing exponentially in Australia, unlike some other countries. On the contrary, if you look at the map some Australian Fab Labs have become inactive (Perth, Ballarat, Sydney). As the two sometimes critical brothers point out, “Digital Fabrication is hard” (p.64)

So, in this article, I want to discuss the hurdles as well as the tremendous potential of setting up a Fab Lab. In 2024, I moved back to Adelaide so will reference the Maker Spaces here.

A Fab Lab needs machines, software, spaces and people who understand (mentors, volunteers)

Space is a huge issue. There are two maker spaces in Adelaide. The Adelaide Maker Space has a huge space in the basement of the WEA Building. The Parks Library Maker Space is part of the library system and has only a smallish room, which does restrict things.

Machines: I listed the 5 types of machines above. An important issue here is enough commonality to allow for interoperability between different Labs around the world. From my reading the most popular machine is the laser cutter. The problem with 3D printers is that they are slow. I noted with interest that Neil Gershenfeld’s favourite machine is the CNC miller. The Fab Foundation site has a page where they specify how to get started and their ideal Fab Lab. For those interested in starting or understanding a Fab Lab there are lots of important details on that page.

Software: Free and Open Source Softwar (FOSS, eg. Inkscape for 2D vector graphics design) lowers the barrier to interoperability but this is not always possible. I’ve noticed some comments in the book (eg. from Nadya Peek, p. 73) about the need to improve CAD / CAM software to make it more intuitive for users

Network effects aka Metcalfes law: the value of a computer connected to the Internet is proportional to the square of the number of computers in the network.

When the digital fabrication hardware and software is interoperable across locations, it enables network effects, greatly accelerating the innovation in a way that is not possible with analog fabrication. I'm wondering if the Maker Spaces in Adelaide could exploit this more. For example, one thing that has surprised me is that although it is very easy to find free 3D print designs online (thingiverse etc.) it is not easy to find laser cut designs. If this global sharing of designs which is embedded in the Fab Lab charter is a reality then why are laser cut designs hard to find?

In this sense digital fabrication is revolutionary but only when linked to the earlier digital revolutions of computation and communication. I have a sense that the Australian Fab Labs are operating too much in isolation from each other and the world global movement.

People: The Adelaide maker space in the WEA basement is staffed entirely by volunteers. This surprised me but it seems to be working. There are induction sessions to get started on particular machines, projects or rooms. There isn’t a formal ongoing mentoring system. If people are stuck then they can ask a volunteer for help. This often works but not always. eg. I had a problem where the laser cutter simply stalled at the start which neither I nor the volunteer could solve.

The Parks library is staffed by a couple of paid workers who are expert makers. They have an induction system and you can make appointments if you need to skill up in a particular area.

Community: I spoke above about killer apps and how I made a Sierpinski Pyramid Lamp. Another way to look at this is about "must haves". What "must haves" do Fab Labs offer? The Blair vision of making one third of your consumables in a Fab Lab may be achievable in the futue but not in the present. The Gershenfelds argue a strong point here: that one of the "must haves" is the sense of community attained through the meeting and making process (p. 77 and 81)

Fab literacy and the Fab Academy: Given that expert people are the main limiting factor for Fab Lab expansion the Fab Academy runs a 24 week course to train people. I’ve had a look at this course and find it quite daunting. There are only two places in Australia where you can complete this course:

• Lake Macquarie's Fab Academy
• Core Electronics

Course details (look here to understand why I find it daunting):

• Program details
• Assignments and Assessment
• Tutorials

Neil Gershenfeld calls this a distributed learning model (a hybrid between F2F and online learning, since part of the learning is done socially at a FabLab). Online MOOCs are notorious for their high drop out rates so it’s an improvement on that model.

Money: Sherry Lassiter from the Fab Foundation estimates that the average budget for launching a community fab lab and running it for 2 years is $250,000. (p. 76)

The Adelaide maker space has various sponsors, scroll down to the bottom of their home page. They have membership fees and fees for visits, inductions and workshops for those who aren’t members.

Neil Gershenfeld has some interesting discussion about who pays on page 42 of the book. He says that selling things made in the lab doesn't work partly because Fab Labs are not setup to make things at scale. He goes on to point out that enlightened government can utilise Fab Labs to help disadvantaged youth stay out of trouble, that is a better option than what happened in Alice Springs (lock 'em up and get more police).

Philosophy: The how, what and why all need to be addressed. "How to make (almost) anything" implies that users have open slather on the what. But in practice that depends on their expertise. Learning works best when the users make something that is personally or socially meaningful, the why. The how is mastery of all the hardware and software which is a big task. But to focus only on that would be a mistake.

Conclusions:

1. How to make many interesting things is not as inspirational as How to make (almost) anything but is more realistic at this stage
2. Third digital revolution and turning consumers into producers are probably over hyping the case
3. Fab Labs / Maker Spaces can have many great outcomes: rapid prototyping, training ground in useful skills for all and joyful community development for starters
4. The future is bright since the technology will continue to improve, become more user friendly and cheaper
5. Australian Fab Labs / Maker Spaces need to tap more into the global movement by sharing their designs (open source philosophy)

FOOTNOTES:

I tend to agree with this amazon reviewer that all the Gershenfelds are wearing rose coloured glasses with their "third digital revolution" rhetoric. Note, however, that in a 2018 article they said that exponential growth of Fab Labs would die out by 2025:

If you want to be proselytized about fab labs, this is the book for you. A key premise is that an analogy of Moore's law will (or should?) apply to digital fabrication. This is based on a few years of doubling of the number of fab labs out there. Moore's original paper was based on 10 years of data but the trend there has continued for 50 years. If that holds for fabbing, yeah, it'll change the world bigtime. But the case has yet to be made. I liked that the Gershenfeld brothers wrote different chapters of the book, with quite different life experiences they bring different perspectives. But it's all based on that exponential premise, one that I'm quite skeptical about. The last of Neil's chapters envisions how fabbing might eventually get to assembling very tiny parts so you could really make anything, but this is almost laughably sketchy and technically infeasible. There's something called chemistry that Neil doesn't seem to be paying attention to. Still, fabbing is a fascinating new technology with lots of possibilities and this book will give you a good feel for how it's affecting some people's lives. There are some good stories mixed in with the questionable extrapolation of trends.

Seymour Papert: The Gears of my Childhood

Original: The Gears of my Childhood

How can we restructure maths to make it more lovable and learnable!? What would success look like?

Seymour covers a lot of ground brilliantly in his 4 page Preface to Mindstorms! His personal learning story which then morphs into a pathway to universal powerful, learning opportunities

He traces his personal learning journey from early childhood when he played around with car gears in the back shed. Seymour fell in LOVE with the gears. He found “particular pleasure” in the differential gear due to its complexity, “the motion in the transmission shaft can be distributed in many different ways to the two wheels depending on what resistance they encounter”. He argues that this love affair became a vehicle for him to later on master school maths. “I clearly remember two examples from school maths. I saw multiplication tables as gears, and my first brush with equations in two variables (eg. 3x + 4y = 10) immediately evoked the differential.”

Another CRUCIAL piece of information about the gears. Good learning materials have a dual nature. They can carry both advanced maths ideas AND sensory motor ‘body knowledge’. You can be the gear.

So far, this is a story of one person’s unique pathway to maths mastery. But not everyone will fall in love with gears:

“One day I was surprised to discover that some adults – even most adults – did not understand or even care about the magic of the gears”

This led him to think:

“How could what was so simple for me be incomprehensible to other people?”

Seymour’s reflection on this question is revealing. He rejected the viewpoint of his proud father that he was clever because he knew people who could do other things he found hard who didn’t understand the differential.

But it slowly led him to what he still sees as the fundamental fact about learning: “Anything is easy if you can assimilate it to your collection of models. If you can’t, anything can be painfully difficult.”

This leads to further questions for educators: How can we create conditions where learners develop useful mental models? How do intellectual structures grow out of one another?

Having a physical manifestation helps here – be it a floor turtle, a Robocup competition vehicle made from LEGO or an attractive shape designed in Turtle Art and then 3D printed.

And to repeat: Seymour fell in love with the gears. He stresses that you need love. He gently criticises Piaget here who focused more on the cognitive than affect.

By the way, later the slogan became hard fun. Whether you prefer love, hard fun or play is ok the underlying message is the important thing: if we like it we will persist in learning it.

When computers came along Seymour envisaged that they could play the role for everyone that the gears played for him. His belief is that many more will fall in love with a cleverly constructed computer based learning environment that taps into natural ways of learning. Hence Seymour helped to invent Turtle Graphics. The computer (Protean machine) can take on a thousand different forms. It can be the universal machine for learners to fall in love with. An incredible leap! Profound yes, True? We shall see.

Of course, since the computer can take on a thousand different forms it can also be used in bad ways:

• Computer as universal machine
• Children’s learning machine
• Game playing machine
• School administrative systems
• Surveillance capitalism machine
• Tik Tok trivial and sinister machine
• Some blame social media for the mental health decline in youth (Jonathan Haidt, The Anxious Generation)

Spawner of revolutions …universal communication and computation (internet, smart phone – banned in schools because too distracting for the youth.

Seymour’s optimistic pathway is one amongst many. Creative learning systems are always there but never dominant in society overall.

I understood this part of Seymour’s message, that the turtle is body syntonic and offers an engaging, a path to mathematical abstraction. Logo / Scratch provides students with a far better chance of falling in love with maths.

What I didn’t grasp firmly enough was the embodiment aspect. I did run a LEGO TC logo group for a while in the 80s but drifted off that path because of the logistic / cost factors of establishing that in the curriculum. More recently, I've corrected that error, after reading Gershenfeld's book, Designing Reality.

In our age, where individual data points have taken on more importance how do we measure or evaluate the mental models that Seymour sees as the most fundamental measure of learning new, useful things? This question was unresolved in Seymour’s view:

“If any ‘scientific’ educational psychologist had tried to ‘measure’ the effects (of Seymour’s encounter with gears) he would probably have failed … A ‘pre-’ and ‘post-’ test at age two would have missed them.”

It’s hard to measure mental models! I see that as the most important challenge arising from Seymour’s article:

“Thus the “law of learning” must be about how intellectual structures grow out of one another and about how, in the process, they acquire both logical and emotional forms”

This is the subject of Marvin Minsky’s book Society Of Mind