Les capteurs – Touch Sensors

Touch Sensors

Apart from the sensors available separately in the starter kit, our friend-in-need, i.e. evive, has a set of inbuilt touch sensors. Under the magic lid, there is a set of 12 pins in the bottom left corner; these pins are the touch input pins.

We can access these pins using evive’s control menu. Let’s have a look at how.

In the menu, you’ll see an option named Touch Sensors. You can access or activate the pins by selecting this option. As soon as you do so, these pins sense, or detect a certain amount of charge present Touch Sensors. You can access or activate the pins by selecting this option. As soon as you do so, these pins sense, or detect a certain amount of charge present; setting it as a reference. If the number of charge increases after connecting anything to these pins, only then will these pins send a signal that something is invading their privacy by touching them; if the amount doesn’t increase, they will consider it as untouched.

Let’s try it out!

From the menu select Touch Sensors by pressing the navigation key to its right. Now, take out a male-to-male jumper wire from your starter kit, and connect it to the pin marked as 1. As soon as you do that, the buzzer will let out a sound, and the number ‘1’ will appear on the TFT screen indicating that the charge at that pin has increased. Now, try touching the free end of the wire; it will not generate any sound. Why is that so?

The buzzer doesn’t make any sound because the charge at this end does NOT go above the reference that was set before connecting the wire; in other words, there is no increase the amount of charge. But we did touch the wire! So, how to make it detect our touch? Simple. We go back to the main menu by center-pressing the navigation key. Now, again select Touch Sensors from the menu. This time when you touch the free end, the buzzer will make a sound and the number ‘1’ will appear on the screen. Whoa! How did this happen?! What is this magic?!

Nope, this ain’t no magic! There is a simple explanation for this: when you reselect Touch Sensors from the menu with the wire still connected, this time the input pin sets the amount of charge at the free end as the reference. That is why when you touch it, the sensor detects an increase in the amount of charge.

Now, let’s try something different. Instead of touching the wire with your free end, touch it with an eraser. Is there any sound? No! How come no sound this time?! The reason is that an eraser is an insulator; therefore, it does not have any free charge inside it that the sensor can detect. We humans, on the other hand, are conductors; we can detect free charges inside us using sensors. That is why it could detect our touch but not the eraser.

You can also try using different objects in your house and see which ones are conductors and which ones are insulators. Similarly, you can also try the same process which different pins and listen to the sounds that are generated for each pin.

Based on this we’re going to making a little something! Yes! We’re going to make our very own piano of 6 keys using evive, 6 male-to-male jumper wires and 6 conducting objects. We’re going to use *drum roll* fruits as our conducting objects! Gather 12 fruits and everything else and get onto it!

1. First of all, insert one end of each wire into each fruit.
2. Later, connect the free end of each wire with each pin.
3. Next, go to the controls menu and select Touch Sensors.

Et voila! Your piano is ready. If you follow the procedure exactly as given, the touch input pins will set the amount of charge available at the fruit end as the reference. Therefore, every time you touch it, the buzzer will make a sound depending on which pin it is.

Enough theory for now! Go ahead and let the musician in you play amazing tunes on the piano!