Aug 122015
RPi. GPIO GPIO.getmode() function

Another new RPi.GPIO feature that I discovered last week is GPIO.getmode(). This appeared in RPi.GPIO 0.5.11 and allows you to query RPi.GPIO to see whether GPIO.setmode() has been set up as BCM, BOARD, or UNSET mode. This could be useful if you are running a suite of scripts or modules which work together. GPIO.getmode() returns… -1 if GPIO.setmode() is not set 11 if GPIO.setmode(GPIO.BCM) is active 10 if GPIO.setmode(GPIO.BOARD) is active Below you can see a live python session showing what you get when you use GPIO.getmode() with different modes set… Why Did You Bother […more…]

Aug 102015

In RPi.GPIO 0.5.10 (we’re now on 0.5.11) Ben Croston ‘deprecated’ GPIO.RPI_REVISION, which used to be the preferred way to find out what kind of Raspberry Pi board a program was running on. This was a useful feature to make it possible to write software that will work on any Pi, regardless of how its GPIO pins are arranged. To date, we’ve had three different GPIO pin header layouts for the standard Raspberry Pis (four if you count the compute module). But GPIO.RPI_REVISION has been deprecated (fallen out of favour) because there is now something better. […more…]

Jun 152015
Flappy Brain EEG controlled game by Albert Hickey @winkleink

At Last week-end’s Cambridge Jam I met Albert Hickey @winkleink, who showed me this extremely cool brain-wave controlled version of Flappy Bird. This is a video post, so I’ll let the video do the talking… Albert runs the Egham Raspberry Jam and his blog can be found here. He’s written the project up and shared the code there. @RasPiTV Thank you for doing this. Will have all set up to play at @EghamJam on the 12th of July. — Winkleink (@winkleink) June 15, 2015

May 182015
Twitter-controlled RasPiO Duino based Pan and Tilt, Tweeting, DropBoxing, Raspberry Pi Security Camera

Around about this time three years ago, I bought and installed five EasyN pan-and-tilt ip cameras to keep an eye on various viewpoints of our houses in the UK and Poland. I think they were about £45 each on Amazon. They’re not too hard to set up and they work tolerably well. The main downside is that their resolution is only 640 x 480 pixels, which is not enough to read a car numberplate from across the street. It’s fairly poor resolution, but you can see something. The colours are a bit washed out too […more…]

Mar 292015
RasPiO Duino as a Lipo Monitor

I’ve been using lithium polymer (lipo) batteries since 2006, when I nervously shelled out £30 for a 3 cell 1600 mAh 10C HiModel lipo to power my EasyStar RC plane. I also spent about the same on a charger and balancer for it. Thankfully, all these things have come down a lot in price since then. I don’t think I’d expect to pay much more than £10 for an equivalent battery now. Typical lipo batteries for large devices have multiple cells. A lipo cell has a no-load resting voltage of 4.2 V when fully charged […more…]

Feb 192015
Interactive Graphing for the Web on Raspberry Pi using

I’d never done graphing on the Pi or in Python before, but for my KickStarter tracker I wanted something that… was web based would work in Python had decent instructions I could get going with fairly quickly I’d seen Rachel Rayns tweet about using for graphing the temperature output of her Chef’s HAT sous vide cooker. I know Rachel loves “human readable instructions”, as do I. So I thought there was a good chance the plotly documentation was good. I decided to give them a shot. Sign Up For An Account The first thing […more…]

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…]