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CoderDojo, Community-based Programming Clubs for Young People

This is a guest blog by MIT Master Trainer Sjaak Bosman.

On April 29th MIT Master Trainer Sjaak Bosman has given a Show & Tell presentation and workshop to introduce MIT App Inventor to children at CoderDojo Rotterdam, The Netherlands.

The original Show & tell presentation can be found at For this workshop it was slightly changed and translated into Dutch.

The intention of a Show & tell presentation and workshop session is showing the ease of use of App Inventor, and to tell about the endless possibilities to let your smartphone do what you want and most of all; to have fun while learning.

In 2016 Sjaak participated in the MIT Master Trainers Program In Educational Mobile Computing to become a certified professional in mobile computing education using the MIT App Inventor platform. Since then his motto is “Computer Science For All”.

Tiemen Waterreus of CoderDojo says:

“For our 35th Dojo in Rotterdam, the Netherlands (last Saturday April 29th) we had the pleasure of Sjaak Bosman visiting us and giving a guest workshop using App Inventor! It was an amazing afternoon, and here’s why:

As a Champion I’m always looking for new workshops and material to work with. Over the years we’ve done a lot of different workshops ranging from Scratch, HTML & CSS to Python, Java and JavaScript.

Having seen App Inventor I’m impressed by its simplicity and the speed in which the Ninja’s can see the results of their work! something that is quite important when teaching kids to code.”

Tiemen continues: “For example; one of the Ninja’s quickly figured out that with a little help of a plugin he could make HTTP calls to a PHP back-end he wrote, setting a key in a MySQL Database that a MineCraft plugin, he built, would poll - so he eventually could control the blocks he was placing using his phone! I’m always amazed by the creativity and problem solving skills of these kids, may I remind you this particular Ninja is 15 years old?”

CoderDojo is a world-wide non-profit organisation that offers free coding lessons for youths of 17 and under. This open source movement started early 2011 in Cork, Ireland but it quickly spread around the world. With currently about 1500 Dojo’s spread over 60 countries all around the world and over 70 locations in the Netherlands alone, you could say it is growing rapidly!

Tiemen concludes “I like to thank Sjaak for introducing us to App Inventor and giving the workshop! If I interested you in CoderDojo and you want to know more? Shoot me an email at

It was a thankful Saturday afternoon. Seeing so many kids having a great time enjoying themselves while discovering and exploring new possibilities: “Computer Science For All”.

Want to know more about Show & tell sessions, please ask me at