Capacitive Proximity Analog Sensor Experimenting

I made a few changes to the code. Obviously need a few more. I made a new sensor as well. This time instead of foil, its aluminum mesh, which works surprisingly well. I like the mesh b/c it will allow me to have LEDs underneath the mesh which can shine up through it. I can eventually put 10-12 3mm LEDs in the area of a 4 inch dia. circle and have this mesh an inch or so above them, so when a hand gets close to the mesh, all the LEDs will brighten up underneath the hand.

I should also add, the PWM for the LED is done with software and is not a hardware PWM pin. The other PWM pins were used to do other things. Will have to refine that a little bit to create a smoother low-brightness transition.


Problems: As you can see, the ambient reference-producing code puts out a reference which is right on the edge and a little bit over as you could see by the LED just barely staying on.

Category:

Science & Technology

Tags:

• Analog
• Capacitive
• Proximity
• Sensor
• Experimenting
• capacitance
• LED
• LEDs
• table
• glow
• light
• up
• sense
• sensing
• hand
• movement
• distance
• how
• to

[grahmaustin]

Alright, the problem with the LED not turning totally off is now fixed.

[killerbeenl]

@siliekas33: It's not smoking I think its a lens effect from the camera. Duh. It is in line with the led. It moves on the frame difference between led and camera refresh rate. or am i wrong :D

[killerbeenl]

Might be that the detecting surface is a little big so there is to much spread. Also might want to increase the offset and the give it a value like if it's x milliseconds/cycles above/below offset then power on port x

[sliekas33]

when you turn of the light you can see that it's smoking :? but yet it's cool :].

[u067120m]

Hi, I would like some of your advice on capacitive sensors. I've just bought an MPR121 cap sense chip, but I'm uncertain about touch sensing and proximity sensing, the main difference is in touching the plate and not touching?

What about the method of acquiring the capacitance, is it the same? Both are connected via a 1plate capacitor and user supplies the other plate for capacitance right? Thank you.

[darthsexiest2727]

nicely done!

[EdgeVetto]

I notice the board is smoking at the end of the video...probably not a good thing

[JalalSela]

This is really cool.... keep it up