Monthly Archives: December 2022

Name that Ware, December 2022

via Hacking – bunnie's blog

The Ware for December 2022 is shown below.

Turning this into a suitable Name that Ware-style entry was a bit tough, but I think maybe I hit a balance between leaving enough clues, and giving it away. We’ll see shortly!

I have a lot more to say about this ware: I will give proper attribution once the ware has been guessed (or the end of the month, whichever is sooner); but let’s just say I was incredibly pleased to find such detailed images in the public domain.

Winner, Name that Ware November 2022

via Hacking – bunnie's blog

The ware for November 2022 is a Keithley 2110-240. I’ll give Rodrigo F. the win, but I’m curious how he knew it was the -240 version; I did not expect someone to discern the line voltage rating from the photos!

Also, thank you Ian Mason for the lucid explanation of the exposed traces near key signals. Here’s his quoted answer, so you don’t have to look it up in the comment thread:

The reason for stripping resist from over guard rings [is] to ensure that any leakage paths come into electrical contact with the guard ring. If you had, say, a bit of flux residue as a leakage path, if it passed between two pins but over the solder mask then the guard ring would be insulated from it and would have no effect. The whole point of a guard ring is that it’s a (relatively) low impedance path either to ground or to a duplicate of the measured signal – being insulated behind soldermask is anything but low impedance.

It’s tricks like these they never teach you in school. I’m guessing it was a hard-learned lesson for the persons who had to figure out that trick on their own. Thanks for sharing the knowledge!

App note: Power MOSFETs in battery management charge-discharge systems

via Dangerous Prototypes

Alpha & Omega Semiconductors app note about MOSFETs used in battery protection circuits. Link here (PDF)

Power MOSFETs are required to be connected in series between the lithium-ion battery pack and the output load. At the same time, a dedicated IC is used to control the on and off of the MOSFET for managing the charge and discharge of the battery. In consumer electronic systems such as cell phones, laptops, etc., the complete circuit system with control IC, power MOSFET, and other electronic components is called the Protection Circuit Module (PCM).
The PCM requires a low on-resistance MOSFET, so N-channel power MOSFETs are usually used. Some applications use P-channel MOSFETs on the positive end due to simple and flexible driving. However, P-channel MOSFETs on-resistance is relatively higher than N-channel MOSFETs and the selection is also limited.

New products: Motoron M2T256 (I²C) and M2U256 (UART) dual motor controllers

via Pololu Blog

The Motoron family keeps growing! We’re happy to announce the release of the Motoron M2T256 Dual I²C Motor Controller and the Motoron M2U256 Dual Serial Motor Controller. Unlike previous Motoron controllers, these boards are “micro” versions that fit the ability to drive two motors (at up to 48 V and 1.8 A) into a minimal, compact form factor. They have the same ability to be individually addressed as the other Motorons, allowing many of them to be controlled independently while connected to the same bus.

A Raspberry Pi Pico on a breadboard using a Motoron M2T256/M2U256 Dual Motor Controller to control two motors.

The M2T256 is controlled via I²C like all of our previous Motorons, but unlike all the others, the M2U256 offers logic-level serial (UART) communication to provide an alternative option for applications where an asynchronous serial interface is preferred. The M2U256 supports the Pololu serial protocol, letting it share a serial line with our other compatible serial controllers (including brushed motor controllers, stepper motor controllers, and servo controllers). Its firmware also includes some options that can help you use it on an RS-485 network (requires addition of external transceivers).

The M2T256 and M2U256 both measure only 0.6″ × 0.8″ and have nearly the same pinout; in fact, both of these Motoron versions use the same printed circuit board with only minor differences in components. (For example, a resonator is only present on the M2U256 because it needs more accurate timing for asynchronous serial communication.) Both versions are available either with header pins soldered in or with headers included but not soldered.

Motoron M2T256 Dual I²C Motor Controller, bottom view.

Motoron M2U256 Dual Serial Motor Controller, bottom view.

The Motoron M2U256 is the latest in a succession of compact motor controllers we’ve produced over the years that use an asynchronous serial (UART) protocol, beginning with one of our very first products, the Pololu Dual Serial Motor Controller. Using this interface made a lot of sense in the past because it was one of the most straightforward ways to communicate with devices using higher-level commands. However, some of the most popular embedded platforms today make it difficult: many Arduino boards use the UART for serial programming, which can conflict with other connected devices, and a Raspberry Pi can output bootloader messages over serial or unexpectedly scale its UART frequency along with its CPU speed.

Meanwhile, I²C has become more popular and easier to use on microcontrollers over time, and it has features like open-drain lines and built-in support for addressing that simplify working with several devices on a single bus. This was the reason for the Motoron family’s initial focus on I²C, which was a departure from our tradition of making serial motor controllers, but the M2U256 reflects our thinking that there are still some reasons to use asynchronous serial. For example, it’s still easier to connect a PC to a serial device (with a USB or RS-232 adapter) than to an I²C device. We expect to make more UART Motorons in the future, too.

Pololu Dual Serial Motor Controller.

Pololu Micro Dual Serial Motor Controller

Pololu qik 2s9v1 dual serial motor controller.

Here is our full lineup of Motoron controllers to date, encompassing both the new “micro” boards and the previously-released expansion boards for Arduino and Raspberry Pi:

Motoron motor controllers
micro versions

M2T256

M2U256
Control interface: I²C UART serial
Motor channels: 2 (dual)
Absolute max
input voltage:
48 V
Recommended max
nominal battery voltage:
36 V
Max continuous
current per channel:
1.8 A
Available versions:
Motoron motor controllers
Arduino and Raspberry Pi form factor versions

M3S256



M3H256

M2S24v14



M2H24v14

M2S24v16



M2H24v16

M2S18v18



M2H18v18

M2S18v20



M2H18v20
Control interface: I²C
Motor channels: 3 (triple) 2 (dual)
Absolute max
input voltage:
48 V 40 V 30 V
Recommended max
nominal battery voltage:
36 V 28 V 18 V
Max continuous
current per channel:
2 A 14 A 16 A 18 A 20 A
Available versions
for Arduino:
M3S256 M2S24v14 M2S24v16 M2S18v18 M2S18v20
Available versions
for Raspberry Pi:
M3H256 M2H24v14 M2H24v16 M2H18v18 M2H18v20

Combining research and practice to evaluate and improve computing education in non-formal settings

via Raspberry Pi

In the final seminar in our series on cross-disciplinary computing, Dr Tracy Gardner and Rebecca Franks, who work here at the Foundation, described the framework underpinning the Foundation’s non-formal learning pathways. They also shared insights from our recently published literature review about the impact that non-formal computing education has on learners.

Tracy and Rebecca both have extensive experience in teaching computing, and they are passionate about inspiring young learners and broadening access to computing education. In their work here, they create resources and content for learners in coding clubs and young people at home.

How non-formal learning creates opportunities for computing education

UNESCO defines non-formal learning as “institutionalised, intentional, and planned… an addition, alternative, and/or complement to formal education within the process of life-long learning of individuals”. In terms of computing education, this kind of learning happens in after-school programmes or children’s homes as they engage with materials that have been carefully designed by education providers.

At the Raspberry Pi Foundation, we support two global networks of free, volunteer-led coding clubs where regular non-formal learning takes place: Code Club, teacher- and volunteer-led coding clubs for 9- to 13-year-olds taking place in schools in more than160 countries; and CoderDojo, volunteer-led programming clubs for young people aged 7–17 taking place in community venues and offices in 100 countries. Through free learning resources and other support, we enable volunteers to run their club sessions, offering versatile opportunities and creative, inclusive spaces for young people to learn about computing outside of the school curriculum. Volunteers who run Code Clubs or CoderDojos report that participating in the club sessions positively impacts participants’ programming skills and confidence.

Rebecca and Tracy are part of the team here that writes the learning resources young people in Code Clubs and CoderDojos (and beyond) use to learn to code and create technology. 

Helping learners make things that matter to them

Rebecca started the seminar by describing how the team reviewed existing computing pedagogy research into non-formal learning, as well as large amounts of website visitor data and feedback from volunteers, to establish a new framework for designing and creating coding resources in the form of learning paths.

What the Raspberry Pi Foundation takes into account when creating non-formal learning resources: what young people are making, young people's interests, research, user data, our own experiences as educators, the Foundation's other educational offers, ideas of purpose-driven computing.
What the Raspberry Pi Foundation takes into account when creating non-formal learning resources. Click to enlarge.

As Rebecca explained, non-formal learning paths should be designed to bridge the so-called ‘Turing tar-pit’: the gap between what learners want to do, and what they have the knowledge and resources to achieve.

The Raspberry Pi Foundation's non-formal learning resources bridge the so-called Turing tar pit, in which learners get stuck when they feel everything is possible to create, but nothing is easy.

To prevent learners from getting frustrated and ultimately losing interest in computing, learning paths need to:

  • Be beginner-friendly
  • Include scaffolding
  • Support learner’s design skills
  • Relate to things that matter to learners

When Rebecca and Tracy’s team create new learning paths, they first focus on the things that learners want to make. Then they work backwards to bridge the gap between learners’ big ideas and the knowledge and skills needed to create them. To do this, they use the 3…2…1…Make! framework they’ve developed.

An illustration of the 3-2-1 structure of the new Raspberry Pi Foundation coding project paths.
An illustration of the 3…2…1…Make! structure of the new Raspberry Pi Foundation non-formal learning paths.

Learning paths designed according to the framework are made up of three different types of project in a 3-2-1 structure:

  • Three Explore projects to introduce creators to a set of skills and provide step-by-step instructions to help them develop initial confidence
  • Two Design projects to allow creators to practise the skills they learned in the previous Explore projects, and to express themselves creatively while they grow in independence
  • One Invent project where creators use their skills to meet a project brief for a particular audience

You can learn more about the framework in this blog post and this guide for adults who run sessions with young people based on the learning paths. And you can explore the learning paths yourself too.

Rebecca and Tracy’s team have created several new learning pathways based on the 3…2…1…Make! framework and received much positive feedback on them. They are now looking to develop more tools and libraries to support learners, to increase the accessibility of the paths, and also to conduct research into the impact of the framework. 

New literature review of non-formal computing education showcases its positive impact

In the second half of the seminar, Tracy shared what the research literature says about the impact of non-formal learning. She and researchers at the Foundation particularly wanted to find out what the research says about computing education for K–12 in non-formal settings. They systematically reviewed 421 papers, identifying 88 papers from the last seven years that related to empirical research on non-formal computing education for young learners. Based on these 88 papers, they summarised the state of the field in a literature review.

So far, most studies of non-formal computing education have looked at knowledge and skill development in computing, as well as affective factors such as interest and perception. The cognitive impact of non-formal education has been generally positive. The papers Tracy and the research reviewed suggested that regular learning opportunities, such as weekly Code Clubs, were beneficial for learners’ knowledge development, and that active teaching of problem solving skills can lead to learners’ independence.

In the literature review the Raspberry Pi Foundation team conducted, most research studies were university-organised on projects to broaden participation and interest development in immersive multi-day settings.

Non-formal computing education also seems to be beneficial in terms of affective factors (although it is unclear yet whether the benefits remain long-term, since most existing research studies conducted have been short-term ones). For example, out-of-school programmes can lead to more positive perception and increased awareness of computing for learners, and also boost learners’ confidence and self-efficacy if they have had little prior experience of computing. The social aspects of participating in coding clubs should not be underestimated, as learners can develop a sense of belonging and support as they work with their peers and mentors.

The affordances of non-formal computing activities that complement formal education: access and awareness, cultural relevance and equity, practice and personalisation, fun and engagement, community and identity, immediate impact.

The literature review showed that non-formal computing complements formal in-school education in many ways. Not only can Code Clubs and CoderDojos be accessible and equitable spaces for all young people, because the people who run them can tailor learning to the individuals. Coding clubs such as these succeed in making computing fun and engaging by enabling a community to form and allowing learners to make things that are meaningful to them.

What existing studies in non-formal computing aren’t telling us

Another thing the literature review made obvious is that there are big gaps in the existing understanding of non-formal computing education that need to be researched in more detail. For example, most of the studies the papers in the literature review described took place with female students in middle schools in the US.

That means the existing research tells us little about non-formal learning:

  • In other geographic locations
  • In other educational settings, such as primary schools or after-school programmes
  • For a wider spectrum of learners

We would also love to see studies that hone in on:

  • The long-term impact of non-formal learning
  • Which specific factors contribute to positive outcomes
  • Non-formal learning about aspects of computing beyond programming

3…2…1…research!

We’re excited to continue collaborating within the Foundation so that our researchers and our team creating non-formal learning content can investigate the impact of the 3…2…1…Make! framework.

At Coolest Projects, a group of people explore a coding project.
The aim of the 3…2…1…Make! framework is to enable young people to create things and solve problems that matter to them using technology.

This collaboration connects two of our long-term strategic goals: to engage millions of young people in learning about computing and how to create with digital technologies outside of school, and to deepen our understanding of how young people learn about computing and how to create with digital technologies, and to use that knowledge to increase the impact of our work and advance the field of computing education. Based on our research, we will iterate and improve the framework, in order to enable even more young people to realise their full potential through the power of computing and digital technologies. 

Join our seminar series on primary computing education

From January, you can join our new monthly seminar series on primary (K–5) teaching and learning. In this series, we’ll hear insights into how our youngest learners develop their computing knowledge, so whether you’re a volunteer in a coding club, a teacher, a researcher, or simply interested in the topic, we’d love to see you at one of these monthly online sessions.

The first seminar, on Tuesday 10 January at 5pm UK time, will feature researchers and educators Dr Katie Rich and Carla Strickland. They will share findings on how to teach children about variables, one of the most difficult aspects of computing for young learners. Sign up now, and we will send you notifications and joining links for each seminar session.

We look forward to seeing you soon, and to discussing with you how we can apply research results to better support all our learners.

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