Jan 282015
Hacking HDMIPi Power Switch with Feedback

In a recent post, I showed you how to hack the HDMIPi power switch so that you can turn the screen on and off from the Pi. But no sooner had I done that than my friend Peter Onion, wondering if there was a way to detect if the LCD is on or off in case it gets “out of sync”, tweeted this… @RasPiTV Is there a switched 3v3 supply to the LCD pannel ? Wire that to a GPIO input pin ? Or can you test monitor "on" via hdmi ? — Peter Onion […more…]

Jan 142015
Hacking HDMIPi Power Switch

The HDMIPi driver board is a fairly complex design. I didn’t design it, although I did have some input into the feature list. I don’t fully understand how it works (something to do with the magic white smoke in the chips, I think), but I have messed around with it probably as much as anyone. Recently, several people have been asking if we can switch HDMIPi on and off programmatically from the Pi. Göran Roseen wants to be able to do it with this HDMIPi based clock… @Raspberry_Pi wall clock with go-to-school indicator that goes […more…]

Jan 052015
Documentation and Commenting Your Code

From observation of the computer industry going back to 1987, when I did a pre-university year at IBM Scientific Centre in Winchester, it seems that the very brightest and best programmers (software creatives) are often not very good at or not very keen on documenting their work. I think the reason for this is often misunderstood. Poor documentation is a source of great consternation in the world of Linux. In fact it’s a large part of the raison d’être for RasPi.TV. We, the users, often feel that the geniuses who write awesome software can’t be […more…]

Dec 062014
CamJam Edukit 2 Launches at PiWars

Today the CamJam Edukit 2 is being launched at the first Cambridge Raspberry Jam PiWars event. I’ll be judging the smallest robot and the best non-competing robot categories at PiWars, but today’s blog is about the kit. This is the second kit in the series, which adds some sensors (temperature, light and PIR) into the bundle. The full kit contents is shown and described below. What’s in the Kit? A 400 point bread board including dual power rails Immersable DS18B20 temperature sensor Light Dependent Resistor (LDR) Passive InfraRed (PIR) sensor Piezo buzzer 4 male-male blue […more…]

Oct 032014
Programming a KickStarter Tracker in Python. Part 2.

So this is part 2 of the KickStarter Tracker in Python. (If you’ve not seen part 1 yet, that’s here.) We got the basics working last time. Now we want to make it look nicer, add more campaigns and have it running continously. So first let’s see about how we can introduce some colour… Adding Colour To Console Output There may well be more elegant ways to get the job done here, but I found a way that uses what’s called “escape sequences”. These are basically codes which can be used to modify the characteristics […more…]

Sep 222014
Programming a KickStarter Tracker in Python. Part 1.

Ever since the HDMIPi KickStarter I’ve been very interested in watching the progress of other campaigns. I’m following four or five Pi-based campaigns at the moment. Are they going to make it? Are they not? It’s nice to keep an eye on things. But monitoring more than one or two wastes a lot of time. Wouldn’t it be nice if I could have a little computer and screen set up so that it checked these campaigns, say, once a minute, and reported on how they’re doing? I know there’s a decent Python library called urllib2. […more…]

Sep 152014
Raspberry Pi SmartWatch Joke

A Raspberry Pi SmartWatch? You’re kidding me right? Errrm. Yes. I mean… Well… This has a lot of the functionality of a smartwatch, but it wasn’t built for that purpose. It’s a little big, for starters. Let me back up and explain. Last week, Apple released photos of their new smartwatch. Twitter, Google+ and every social network was awash with photos, comparison photos, criticism, analysis and good old-fashioned Apple-hating. By Thursday I was rather bored of it all, so I decided to make a joke tweet. I had this rather large Vacuum Fluorescent Display (VFD) […more…]

Sep 012014
RPi.GPIO - port function checker

A few weeks ago I blogged about RPi.GPIO updates for the model B and updated my RPi.GPIO documentation and quick reference sheets. But there was one feature I held back on because I needed a bit more time to mess about with it. (And then got busy with other things.) So What Was It? gpio_function() Another RPi.GPIO feature that sneaked in while I wasn’t looking is gpio_function() This is a feature that’s been inserted in RPi.GPIO to enable you to query the setup status of a port to see how it’s configured. import RPi.GPIO as […more…]

Jul 262014
RPi.GPIO Quick Reference updated for Raspberry Pi B+ and A+

Having brought my RPi.GPIO documentation (almost) up-to-date with the previous blog post, I realised it was time to update my RPi.GPIO Quick Reference ‘cheat sheet’ as well. It’s quite a useful reference. Page 1 gives you the basic RPi.GPIO commands and usage. I like to take one of these the Jams in case someone needs help and I can’t remember the necessary commands. Page 2 has a Raspberry Pi GPIO pinout diagram for all versions (except compute module). This part has been updated to add the pinouts for the B+ (and A+). Page 3 gives […more…]

Jul 252014
RPi.GPIO update and detecting BOTH rising and falling edges

A few days ago, Ben Croston updated the RPi.GPIO Python library so that the ‘board’ pin numbering system would work with all of the pins on the B+. It doesn’t really affect the way I work, as I always use BCM port numbers. They already worked on the B+ and the compute module. While he was at it, he made a couple of bug-fix tweaks. Looking at what was tweaked, I realised there are a couple of features of RPi.GPIO that I hadn’t yet documented. In this blog post I hope to update my RPi.GPIO […more…]