Feb 032016
 
Using MCP3008 to measure temperature with GPIO Zero and RasPiO Pro Hat

In the previous article I showed you the GPIO Zero Experimenter’s Kit I put together to go with the RasPiO® Pro Hat. Today I’m going to give a quick overview of how to use the MCP3008 analogue to digital converter to read the TMP-36 temperature sensor. This gives us a temperature reading (in °C) that we can use to make “decisions” in our Python program. In our case, we’re going to switch on a red LED when the temperature is 24 °C or greater. But there are all sorts of other things you could do, […more…]

Jan 152016
 
RasPiO Pro Hat  - Putting Pi Ports in Perfect Positions for Productive Play

Today I launched the RasPiO Pro Hat on Kickstarter. It’s a Raspberry Pi Hat for GPIO tinkering (it goes perfectly with GPIO Zero). It arranges the GPIO ports in numerical order around a mini-breadboard, which, to my knowledge, has not been done before. It also replaces the RasPiO Breakout Pro (now end of life) because it protects all the ports from over-current and over/under-voltage as well. It should prove a very useful board for GPIO tinkering and education. Have a look at the video and pop on over to the RasPiO Pro Hat campaign page […more…]

Jan 072016
 
Always Test Everything - Twitter App Update

I’m a firm believer that you should always test things in advance. It helps avoid unexpected last-minute panics when things don’t work as you expected them to. On Friday I’m going to pick a winner from my twitter followers using the twitter app script I wrote back in October 2013. My Joey from @gooligumelec just arrived. :) I have a spare I will give to a randomly selected follower on Friday. pic.twitter.com/yGtwATYXng — RasPi.TV (@RasPiTV) January 5, 2016 It Still Works, But… Since I had no idea where the SD card with that old Raspbian […more…]

Nov 182015
 
7 segment display Python Raspberry Pi - countdown ticker

Continuing with our theme of 7-segment displays driven directly from the Raspberry Pi’s GPIO using Python, I was asked for an explanation of the code from the previous post. In order to explain something, you first have to fully understand it, so I took some time to have a good look at the ‘business end’ of Bertwert’s code and figured out exactly how it works. I’ve now put a full code walkthrough of that script in the comments section of the previous post. Having done that, and having had a tweet from David Meiklejohn saying […more…]

Nov 162015
 
How to drive a 7 segment display directly on Raspberry Pi in Python

Last week I bought some 4-digit, 7-segment displays to experiment with. Strangely enough it was something I’d never tried before, so I was interested to see how they work. I googled around looking to see if someone else had done this before. It seems there are several different sorts of 7-segment displays, so you have to find a good match for the one you’ve bought. You can get them in various guises including: i2c backpack; 12 pins; 16 pins; resistors built-in; common anode; common cathode etc. The ones I bought are 12 pin, bare, no […more…]

Oct 222015
 
RasPiO GPIO Ruler goes on general sale

You may remember I ran a KickStarter campaign in August for the RasPiO® GPIO Ruler. The KickStarter rewards were all sent out in the first week of October. (We finished shipping 3 weeks early.) So now it’s time to launch the product officially and make it available to all on general sale. If you missed out on the KickStarter, now you can buy one. In case you haven’t seen it before, this is what it looks like… What Is The RasPiO® GPIO Ruler? It’s a coding crib-sheet for RPi.GPIO, a port ID guide, a multi-scale […more…]

Oct 152015
 
GPIO Zero Test Drive - Making Light of Security

Giving GPIO Zero (Beta version) a test drive might make you feel a little insecure, but I’m aiming to throw some light on the situation. I decided to try out some of the built-in features of GPIO Zero by working up a little hardware project. I looked at the current feature set and decided to try and combine MotionSensor, LED and LightSensor all at once. What sort of project uses that kind of technology? Why a PIR-controlled security light of course – if you swap the LED for a relay and 12V lamp! The video […more…]

Oct 122015
 
GPIO Zero - Introduction

If you’re a RasPi.TV regular, you’ll know that one of my very favourite things is hacking around with the GPIO ports on the Raspberry Pi and sharing my findings with the world. Sometimes this involves documenting a new feature, sometimes it involves making a new project, using a new chip or just getting something working that I haven’t tried before. But it nearly always involves Python programming and the brilliant RPi.GPIO Python library by Ben Croston. I’ve written all sorts of tutorials (~16) on RPi.GPIO because it is one of my favourite things. You may […more…]

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
 
RPI.GPIO New Feature GPIO.RPI_INFO replaces GPIO.RPI_REVISION

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…]