Launching Prewired Online

3 minute read

All of us on the Prewired team were really sad about having to close down our regular Wednesday evening sessions in the face of the Covid-19 emergency. But we started thinking about making the most of the internet and … tadah! we decided to launch Prewired Online! A few of us — trustees and volunteers — have spent the last couple of weeks experimenting with different videoconference systems and we ended up choosing Blackboard Collaborate as the best option, at least for the time being.

Our first go at running the online session (1st April 2020) was a lot of fun. We started small and tried not to be too ambitious. Freda began the session by giving a quick tutorial on how to use Collaborate and everyone had a go at chatting, raising their hands and unmuting their microphones. Some chaos, but also some good laughs.

After all the participants had a chance to say what they’d been up to recently, we created a new virtual ‘breakout room’ where James (@jamesmraymond) ran an introductory workshop on machine learning systems that work a bit like brains. These neural nets use a network of nodes with inputs and outputs; they have turned out to be very good at deciding how to classify various kinds of inputs once they have been trained with appropriate data. James then gave an impressive live demo with the Teachable Machine website on how to teach a neural net system to distinguish between pictures of apples and bananas. And between pictures of bananas and pictures of himself! We also had a quick look at another web site that uses machine learning to recognise images that you can upload yourself: Cat Detector. James pointed out that these systems are making a kind of guess based on the training data — usually, the more data the better. The machines may be pretty confident that their guess is correct, or else fairly uncertain. Pretty much like human beings! And sometimes they guess wrong, with potentially dire consequences in the case of self-driving cars.

To round off the session, Colin presented us with a coding challenge to work on over the coming week.

Shared Birthday Challenge

Suppose you invite a bunch of your friends over to your house. How many people do you have to invite in order to have a good chance that at least two of them have the same birthday? It's possible to do some maths with probability theory to solve this, but Colin wants us to write code that simulates a way of solving the problem. That is, the code should do something like adding together a certain number of people and then checking their birthdays to see if there is a match. If you repeat this checking process enough times, you should get a reasonably good approximation of how many people you need to invite in order to get, say, a 50% chance of a match. At the next session of Prewired Online (Wednesday 8th April, 5:30 pm), you will have a chance to present your solution — it doesn't matter if you didn't manage to make it to the session on 1 April. You can write your program in any language you like (Colin claims he did one in Scratch :smile: ). You might want to think about what's particularly cool about your solution: is it concise? readable? fast? has a nice interface? Whatever.

We are looking forward to seeing you at the next session of Prewired Online on 8th April. If you want to be sure of getting updates on how to join the videoconference, be sure to sign up to our mailing list.