Actions
Forum Thread Details
  • State Suggested Answer
  • Replies 7 replies
  • Answers 1 answer
  • Subscribers 473 subscribers
  • Views 762 views
  • Users 0 members are here
Related

[ESC] Capacitive touch PIC for a dollar

Catwell
During a visit to the ESC expo in Chicago, I stumbled across Microchip's PIC16F707 microcontroller. The next big thing from Microchip, as they told me. The main feature making this particular uC stand out is the mTouch, projected capacitive touch-screen sensing technology, built right into the chip. And to top that off, you get royalty-free code to use for developing mutitouch interfaces. This chip is currently only supporting 2 simultaneous inputs, but the code also supports gestures. So, this is leaps and bounds over the classic single touch environments of the past. The absolute best part of this whole offering is the price, $0.99 cents in volume, and approximately $3-$5 dollars for small quantities.


Now, what is a good source for capacitive touch panels?

 
What I want now is a PIC with multitouch and PWM motor driving capabilities.


Cabe
Attachments:
image41418A.pdf
  • 0

    hi,

     

    Microchip always makes innovations in their product portfolio with reasonable prices.

     

    But i have a question.. : a capacitive touch panel versus a resistive touch panel. Which is the best ? What are their advantages and disadvantages ? In which application would we better use which one ?

     

    Firat

  • 0 in reply to firatkocak

    Firat,

     

    It depends on your application. Resistance, until recently, only allowed for a single touch to be registered. So, often were used to create simple GUIs, buttons, menu systems, with simple dragging of a single point. And with resistive, people wearing gloves can actuate the screen. Often useful for medical and industrial environments. Resistive is also prone to drifting in it's touch accuracy. So, regular calibration is needed. However, they are pressure sensitive, so you can detect light to heavy presses. And resistive often has a rather spongy, elastic screen surface.This, as I've seen, can really wear out the screen if it consistently get's pounded on by users.

     

    Capacitive needs an actual electrical connection made on the surface, either with a bare finger or conductive stylus. Some companies are making gloves that are conductive now, but major adoption of that feature may be way off. Capacitive often has a hard surface, glass or plastic. Which can tolerate some rather heavy use. But, the screens are not indestructible. I have seen workers user wrenches and screw drivers on capacitive panels before, and, or course, end up cracking the screens a bit.

     

    Just a brief overview of the difference. Hope this helps.

     

    Cabe

  • 0 in reply to Catwell

    Hi Cabe,

     

    Thank you very much for the information. It really helped. Currently i have two projects in my mind. First will be an industrial controller for temperature and humidity, so it will be used in dusty environments. The second one will be used in office or home areas and it will be lightment controll application. I think resistive touch panel is better for me. I have a Cypress Cap Sense dev kit but i could not have a chance to examine it yet. I think i should give it a try for testing capacitive technology.

     

    Thanks again.

     

    In the meantime, i am fallowing almost all of your messages. Honestly, thanks god that you are a member of Element-14.

     

    Firat

  • 0 in reply to firatkocak

    Hi Firat,

     

    may i know which demo board from cypress you have? and

     

    what is your project requirement so that i can help you in suggesting right device

     

    Best Rgds

    Bheema

  • 0 in reply to firatkocak

    Hi Firat,

     

    A resistive touchscreen panel is composed of several layers, the most important of which are two thin, metallic, electrically conductive layers separated by a narrow gap. When an object, such as a finger, presses down on a point on the panel's outer surface the two metallic layers become connected at that point: the panel then behaves as a pair of voltage dividers with connected outputs. This causes a change in the electrical current, which is registered as a touch event and sent to the controller for processing.

     

    A capacitive touchscreen panel consists of an insulator such as glass, coated with a transparent conductor such as indium tin oxide (ITO).[6][7] As the human body is also a conductor, touching the surface of the screen results in a distortion of the body's electrostatic field, measurable as a change in capacitance. Different technologies may be used to determine the location of the touch. The location is then sent to the controller for processing

     

     

    Technology
    		4-Wire ResistiveSurface Acoustic Wave5-Wire ResistiveInfraredCapacitive
    Durability3 year5 Year5 Year5 Year2 Year
    StabilityHighHigherHighHighOk
    TransparencyBadGoodBadGoodOk
    InstallationBuilt-in/OnwallBuilt-in/OnwallBuilt-in/OnwallOnwallBuilt-in
    TouchAnythingFinger/PenAnythingFinger/PenConductive
    Intense light-resistantGoodGoodGoodBadBad
    Response time<10ms10ms<15ms<20ms<15ms
    Following SpeedGoodLowGoodGoodGood
    ExcursionNoSmallBigBigBig
    Monitor optionCRT or LCDCRT or LCDCRT or LCDCRT or LCDCRT or LCD
    WaterproofGoodOkGoodOkGood

  • 0

    Is supporting capacitive sensors, even with "multitouch", the same as supporting capacitive touch "screens" ?

    the PIC16F707 appears to support two sets of sensors with up to 16 buttons each, which I think implies:

    1. if you want multitouch, you'd only have 16 available buttons.
    2. that's individual buttons; not a high-res touch-screen thing.  I don't know if it's possible to scan a matrix of sensors or not.
  • 0 in reply to bheemarao

    Hi Bheema,


    It is CY3203A - CapSense Successive Approximation (CSA)  Training Kit. I think ,Capacitive touch sensing is not good for a industrial application. But in the Lightment Controller, it may be used. I am thinking of designing a slider to control the light intense in a room or office or where it is available.


    I am just thinking and have not started yet. An also thanks for your fallowing message.

     

    Firat