I was away this week so Dave led the group, they did a couple of Arduino projects. They revisited the traffic lights from December but this time used the Arduino to control them and then moved on to a temperature and humidity sensor called the DHT11.
Here is the wiring diagram for the traffic lights and you can find the code here.
Here is the wiring diagram for the DHT11 and the code is also on Dropbox here.
We will be doing more with the Arduino particularly for some of our projects.
We started of this week’s session by looking at the recent Soyuz rocket launch which was to send two people to the ISS. During the launch one of the booster rockets failed and the launch had to be aborted. Both crew members, astronaut Nick Hague and cosmonaut Aleksey Ovchinin, escaped without injuries.
Official astronaut portrait of Tyler (Nick) Hague – Blue Flight Suit Picture. Photo Date: January 13, 2014. Location: Building 8, Room 183 – Photo Studio. Photographer: Robert Markowitz
We then continued to work on our pictures and messages for the Mission Zero Challenge. I made a video of some of the work we did, but it’s very hard to film LEDs so the quality is very poor.
If you want to find out more about the Soyuz incident and have another look at how to make pictures and messages with the Sense-hat LEDs my notes are here day 4.
Next Saturday we’ll start looking at Pygame Zero. See you all then.
In the Bodgers group, we’ve been working on code for the International Space Station. To do this we are using on online Sense Hat emulator, the Sense Hat is a special piece of hardware designed to be deployed with a Raspberry Pi on the ISS.
Hello again everybody.
This week in the Bodgers group we started working on our code for the Mission Zero Challenge.
We began by writing a simple text message on the 8×8 full-colour LED display, then we changed the text and background colours. We then coded a picture by assigning a colour to each of the 64 LEDs on the display. We finished the session by taking a quick look at using the temperature sensor to read the temperature. Here are my slides from this week day 2.
Next week we will recap what we covered this week and we will start to personalise our code for the challenge.
In the meantime, here’s a couple of fun videos on how the Astro Pi computers got to the ISS.
Last Saturday we had a look at how we might figure out how far and how fast a bike is going using a Raspberry Pi. We used a very basic set up with just a micro-switch attached to a toy trike with a little nut taped to the front wheel, each time the wheel rotates the nut would “click” the micro-switch.
We would need to use a reed switch or a hall effect sensor and a magnet attached to the wheel if we were to use this on a real bike.
We started of our coding by looking at the time.time() function. This function returns the number of seconds, in decimal form, since 01 January 1970. If we want to time an event all we have to do is use time.time() to get the start time and use it again to get the end time and then subtract the the start time from the end time.
We used this to get the the amount time it takes to do one rotation. Now we want to find out how many rotations we have per minute or RPM (revolutions per minute). As our result is in seconds the easiest thing to do is calculate revs per second so we divide 1 by the time it takes to do 1 rotation and then multiply the answer by 60 to get RPM.
Now we wanted to get KPH(kilometres per hour) so first we measured the circumference of the wheel and found it was 50cm or 0.5 Metres. We then calculated metres per minute by multiplying our RPM by 0.5 and we then multiplied this by 1000 to get KPH.
Here’s a picture of what our results could look like when displayed using Pygame. We will look at Pygame later on as it’s an excellent way of displaying information.
Last week in the Bodgers group we began by looking at our new keyboards and Touchscreens. These will allow us to easily design touch based projects and projects that need a monitor. They will also be invaluable at the start of next years sessions as we can get our code on the Raspberry Pi straight away without any need to connect our laptops.
We also started planning our next project with a short brainstorming session and we have a couple of ideas we will develop further this week.
I was away this weekend so Dave looked after the group.
He covered some basic electronics theory such as Ohms Law, how we use resistors in our circuits to protect other components and how to wire up an LED. He also helped the group build a simple traffic light circuit controlled by an Arduino which they then programmed.
The Raspberry Pi Foundation have announced that they are not running the Pioneers Challenge this year and are instead concentrating on the Coolest Projects. This means that Coolest Projects is now open to Code Club and Raspberry Jam members. There will be a UK Coolest Projects in April in London and Coolest Projects in Dublin will now be called Coolest Projects International. See more info here.
We have two sessions before the mid-term break so we will concentrate on coming up with ideas for our next projects and how we might implement these ideas and that will leave us a couple of weeks to get components etc. organized.
This week we continued to play with the Sense HAT and as we’ve been mostly focusing on projects so far this year we took the opportunity to look at some of the theory behind programming.
We looked at how we use variables, loops and decisions in our programs and we also learned about algorithms. An algorithm is a set of rules we can use to solve a problem for example an algorithm to determine if a given year is a leap year. A year is a leap year if it is divisible by four, but not by one hundred, unless it is divisible by four hundred.
We then worked on a program which would allow us to “move” an LED around the LED matrix on the Sense HAT. You can run our code on the trinket.io Sense HAT emulator.
Dave will lead the group next week when he will cover some basic electronics.