zondag 31 augustus 2014

Espruino roadtest - the (not so) useless machine

Espruino roadtest

I received an espruino microcontroller to test and review for element 14.
An espruino is a microcontroller which is runs javascript.



However, when I received the espruino I had limited time and we were soon to go on holidays for three weeks to Italy. Besides that it was also an objective to involve my son in programming the espruino.

So I came up with a simple idea to create a useless machine, not as sophisticated as many do but just a simple device to experience the programming and the hardware.


The idea of a useless machine is that when you flip a switch an arm will appear and switch it off again. In our design the arm is not hidden, but in a 'rest' position.

Just before we went to Italy my son and I made the board on which the switch and servo were mounted and I made a PCB with some connections for the battery, servo and switch. I also soldered a resistor for the pull-down configuration and connection headers on the espruino. The hardware was finished, now only the software needed to be done.

One nice part of the espruino is the IDE. 

You can start with the graphical interface (blockly https://code.google.com/p/blockly/) and when you feel limited you can switch to the textual interface (javascript).
Graphical programming using blockly

A very nice aspect of this interface is that you can enter a command in the terminal interface and this command will be executed immediately. In this way you can test a command easily and when satisfied continue with your coding.

One other very nice aspect is that you can use the IDE on a lot of OS'es (Windows, OSX, Linux, etc.). I use a chromebook and this is the first microcontroller that I can program completely from my chromebook.

I like the espruino very much, it's easy to use and works very well with my chromebook. Also it's great for kids, my son really liked the blockly and coding with it!





After some explanation of servo's, pulses, frequency etc. my son was able to program the espruino so the useless machine worked:
The pulse and the pull-down resistor

the 3 blocks of our program