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Pi Friday with Tim

I’m Tim, and I have been involved with ARM processors and Smalltalk since the early 1980s, working on various projects on the earth and orbiting it. More recently I have been involved in the Raspberry Pi project (using Smalltalk to make a better Scratch for all those young programmers on the Pi) and creating replica AstroPi Flight Cases (like those on the ISS). I have also been running the workshops at BC Robotics for a few months now. For those unfamiliar, we run workshops focusing on the Raspberry Pi, and recently, the ESP8266 in Arduino.

In addition to the workshops, you will also be hearing from me one Friday a month – I will be posting a Pi Friday segment on the site with a few interesting tidbits and tricks surrounding the Pi. Hope you enjoy!

There’s ‘new Pi’ in two different ways.

First and most obviously is the new Pi 3B+ released a few weeks back, and now arriving in noticeable numbers in people’s mail. This is a modest revision of the Pi 3B that we’ve had for the last couple of years, sporting an updated SoC that runs a bit faster and a bit cooler (due in part to turning the silicon upside-down and re-wiring some of the power lines). It has improved USB & PXE booting support and perhaps most importantly, faster Ethernet (with support for PoE) and WiFi. The changes to the WiFi setup include a shield over relevant bits so that the entire board is now FCC certified, which is nice for those of us making products from Pi.

So, good news – faster, better, same price. Bad news – err, well… none really. Except it may be a while before they’re commonly available.

Second and arguably even cooler is the launch of the Astro Pi upgrades to the ISS. The two Astro Pi units on the station are getting some new software and even WiFi dongles! The little care package blasted aloft from Baikonaur with astronauts Feustel and Arnold, and cosmonaut Artemyev and docked with the ISS at 1940GMT last Friday. The AstroPi project has its own website at https://astro-pi.org and rather nice, if a little pricey, replicas of those oh-so-cool space certified cases are available from our friends at www.astropicase.com

Cool trick for your Pi

If you attach a momentary contact switch or pushbutton to pins 5 & 6 of your GPIO (or if you prefer pins BCM3 and the adjacent ground) then you can make use of a neat device tree file to create a simple on/off power button. As long as you have a recent Raspbian Stretch installed you should find a file named: ‘/boot/overlays/gpio-shutdown.dtbo’ – enabling the function should be as easy as:

In a terminal enter:
ls /boot/overlays/gpio*
and make sure you have the item listed /boot/overlays/gpio-shutdown.dtbo

If you have that file, enter this in the terminal:
sudo nano /boot/config.txt

then scroll down to the bottom of the file and add this line:

then save with ‘ctl-o’ and exit with ‘ctl-x’ and finally reboot your Pi.

Now when you press the button the system will do a clean shutdown. Once the green activity led stops blinking you can remove the power or, and this is where it gets even cooler, just press the button again. Because GPIO3 is also connected to the run line it will make the Pi restart!


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