Hi everyone!
I would like to share the project I have been working on here.
Through a project in my university, I was inspired by trying capacitive touch sensing.
I learned about the technology through instructures and used what I learned here and elsewhere on the Internet to build my own connection
Controller controller, I use it to mix different RGB values to create interesting light colors.
First of all, when I started this project, I didn't know anything about electronic and capacitive touch sensing.
Some of the problems I had earlier were caused by misconceptions about what actually happened.
So let me briefly introduce from my understanding: the capacitor sensor uses multiple components, mainly: Capacitance (
In this project, we use aluminum foil, but we can also use conductive fluid, etc), wires (
Of course, its electronic products)
And a resistor, anything below 10 mohm, the resistor is too small for direct contact.
It works by measuring the time difference between point a and point B.
Send a signal from the start pin to the end pin and measure the time required using a timer.
By reducing the resistance value (
By moving the capacitor (
In this case, your hand)
Capacitance near the sensor (
(Aluminum foil)
This time is shortened, and the difference in time is given by the sensor as a value.
Since the sensor is affected by the capacitor surface, the data may be very unstable due to interference.
This can be solved to a large extent by properly insulating the capacitor and using the ground (
I will show it later).
So now we can't start counting everything we need: Electronics: 1.
2x22 M ohm resistance (
The larger the resistance value, the farther your sensor reacts, I personally used 22 M ohms and the minimum value I experienced to get the available data is 10 M ohm)2.
3x330 ohm resistance. Wires4. Breadboard5. Circuit board (
The mine has continuous copper tape)6.
Multiple co-cathode RGB LEDs (
I used 8 but how much light you can have depends on how much light you want)7. Foil8 aluminum. Cling wrap9. Arduino Uno10. TapeThe Case:1.
The wood I use is 50x1. 8 CM MDF(
You can really use anything.
It depends on the effect you want and the tools you can use)2.
I used an acrylic plexiglass of 50x0. 3 CM(
Or any other transparent/translucent material such as rice paper)3. Sandpaper (fine sandpaper)4. Wood-glue5. veneer (optional)6.
Acrylic gluttls: wire stripperSoldering iron tinStanley knifedrillSaw (
I used a saw)
Now that we have everything, we can start making a prototype to see how it works: Preparation: Cut 4 rectangles from the aluminum foil (
Mine is about 10 cm by 5 cm)
, Wrap these in plastic wrap to prevent them from coming into contact directly and stick the wires to the aluminum foil.
I just put a stripped end on the foil (
As long as they keep in touch).
To ensure safe insulation of aluminum, I wrap it with plastic wrap and iron it between paper (
Just a few seconds so it won't melt completely).
Then set the circuit as shown in the figure.
Pin 4 is used as a sending pin for both sensors, while the receiving pins are pins 2 and 5.
You can use multiple send pins, but it can cause trouble because they are not fully synchronized.
Before welding everything together, use this setting for debugging purposes to make sure everything really works as expected.
Now that we have everything, we can start debugging the sensor.
To use my code, you should download the capacitor Sensing Library from Arduino and install it in the direction given on the reference page: click the meThe code :(
I'm not good at coding, so do this if you know how to code better)
What this code does is to extract the original data from the sensor (
These data are always a bit unstable due to all the different factors that affect the sensor)
When the array reaches the maximum value, it continuously puts the original data into the array (in my case 10)
It clears the last value and adds a new one.
Each time a value is added, it calculates the average and puts it in a new variable.
This average variable is used to map values to values from 0 to 255, which is the value we write to the RGB pin to increase the brightness of each channel (
Channels for G and B).
Now, if you upload the code to arduino, turn on the serial monitor and you should see the lower RGB value when you hover your hand over each sensor.
Case: I made the case through my university using tools, so this workflow does not work for everyone.
However, there is nothing special about it, it needs a hole on one side and the USB port to go through, other than that it is just an open top box.
The size is as follows: transparent top 15x15 CM, Wood bottom 15x8 CM (
The thickness of wood is 1. 8 CM for me).
I used a table saw to cut a plate of mid-fiber boards into the correct size I needed (
15x8 CM and 1 15x15 CM ground panel)
After that, I cut the corner to 45 degrees.
All the parts I glued together with the glue and clip (
Let it dry for at least 30 minutes)
, I used the same procedure for plexiglass, but used a special saw blade.
1 the center of the arduino USB plug height on the wooden side should have a hole to allow the arduino to be inserted.
I finished the base with a single board.
I cut it into pieces a little larger than the surface on both sides.
I stick this on it and clip it for 30 minutes each side (
It's better to do it alone so you can make sure it doesn't slide and after drying I'll cut off anything that stands out.
I use a bottle cap that is glued together with a glue specifically for Acryl called Acryfix.
Please note that if you use acrylic plexiglass, the glue will dissolve the plexiglass slightly, so be as accurate and fast as possible (
Dry within minutes, but exposed to air within seconds).
I scrub the cube with a sand blasting machine to finish the lid, but you can also use fine sandpaper, which takes more time to make it look more uniform.
Please note though that if you use sandpaper, it needs fine-grained and glue the parts together after the frost process (
So you don't accidentally break it because you put a lot of pressure on it)
To make sure the lid doesn't slide too much, I stuck a few small wooden strips on the edge of the wooden cube.
If you have a circuit board, you can start welding all the parts together using the same settings of the breadboard.
For ease of use, my circuit board has continuous copper bars.
For each sensor, I cut a small square and weld the resistance and wires to it.
Send wire (
Wire from pin 4 to each sensor)
Welded to a separate square in sequence, there is 1 line into pin 4.
I keep a long rectangle to make a simple led strip (
Measure it so that it fits inside the lid but is on the edge of the base).
You can weld LEDs in turn (
Keep in mind that in the image where I accidentally welded LEDs and resistors on the wrong side of the board, the copper bars should always be below).
When you weld the individual parts together, put them into the shell.
I didn't weld my individual wires together, so I could easily replace them if needed.
The time to put everything into the base: this is almost the easiest step, and the arduino needs to first place the USB port through the hole on the back of the chassis.
Now add sensors to make sure that the sensor foil fits the wood on both sides, and the ground foil goes straight to the wood.
When all of this fits well, insert the RGB led into the correct pin (9, 10, 11)
Let it rest on the edge of the base.
If you 've done all of this, you should now have a working light with a capacitive touch color mix. Have fun!