Goblin detector and Jam review – a guest post from 8-year-old Annabel

Liz: Annabel Oakley is eight years old. That makes her our youngest ever guest blogger! Here’s her account of a day out at a the PyCon UK Raspberry Jam in September at Coventry University, and the goblin-scaring project she made with her Raspberry Pi. Thanks very much, Annabel – and thanks also to Dad, who helped out with the Goblin Detector and drove the car!

Annabel wanted a project to show at the  computer conference. She decided to make a Goblin Detector which would sound a buzzer and flash a light, when her brother or sister went in her bedroom.

goblins

Annabel used a Raspberry Pi computer and a motion sensor.

Annabel and goblin detector
Her dad showed her what to do, and Annabel wired it up and wrote the program to control it.

goblin detector
The program was written in a computer language called Python. The Goblin Detector has a motion sensor in a margarine tub. It connects to the Raspberry Pi using three wires.

wiring

The Raspberry Pi has an add-on called Pibrella which gives it three lights, a buzzer and a button. It waits 5 seconds to let you get out of
the room, then it waits for movement. When it sees movement, it sounds a buzzer. You can press the button to stop the buzzer, and it will wait for movement again.

Pibrella
The motion sensor is very cheap, only £3, and can be found in light switches which turn off automatically. It has three wires:

• Positive
• Signal
• Negative

The program waits for a high current on the Signal wire, which means it has seen some movement. You can find out how to make and
program one yourself on Annabel’s dad’s website.

Then Annabel and her dad set off for the computer conference. The ticket was only £5 for children!

Annabel, book
When Annabel got there, she got given a goody bag which included a brand new Raspberry Pi, a book and other goodies!

Annabel wrote a program to put the words “Hello World” on the screen in Minecraft.

programming

Some teachers were also at the conference. The teachers were learning how children used computers.

programming
There were also some computer programmers helping the children and
teachers. The grown-ups were not allowed to touch the keyboards. The children had to do everything themselves! There were lots of grown-up computer programmers around to help out, and some of the children were already experts.

Lots of people were interested in Annabel’s Goblin Detector.

kids
We let the children take it apart and program it for themselves. It was easy to put it back together.

Most of the children at the computer conference were girls. There was a whole pack of Brownies!

girls

Annabel also saw some robots which  could be programmed to dance.

robot
Annabel made a friend called Sam and they wrote a program to take lots of photos, and then turn those photos into an animated video.

sam and annabel
There were some famous programmers helping out, such as Carrie Anne Philbin and Ben Nuttall, who work for the Raspberry Pi charity.

Miss Philbin, famous programmer
Sam and Annabel had to show off their animation to everyone else.

demo

You can watch their 8-second animation here.