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I have a VCC CTH series touch screen push button, model CTHS15CIC05ONOFF, which I'm trying to use in a circuit to no avail.

As far as I can tell from the datasheet, this is how to wire it:

circuit

The LED lights up, but no button presses are detected when I touch the button. I've tried the same wiring set up with a plain push button and it works as expected. I've also tried a variety of resistors from 1kΩ to 100kΩ. What am I doing wrong?

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  • \$\begingroup\$ Please read the datasheet again. On page 4 it is stated pin 1 is Vdd, pin 2 is the output and pin 3 is the LED anode. You may have fried the device by connecting it the way you did. \$\endgroup\$ – Janka Jan 22 '17 at 0:10
  • \$\begingroup\$ No worries, that's why I buy a few of each component when I don't know what I'm doing. :) I'm not sure I understand though, if pin 1 is Vdd, doesn't that mean it's the input voltage? Same with pin 3; it's the input for the LED? And pin 2 is the output of the switch, correct? \$\endgroup\$ – shanet Jan 22 '17 at 1:35
  • \$\begingroup\$ Vdd is the supply voltage for the circuit inside the button. Pin 3 is the anode of the LED, a resistor to Vdd goes there. Or a resistor to an arduino output which controls the LED. \$\endgroup\$ – Janka Jan 22 '17 at 1:44
  • \$\begingroup\$ Okay so then pin 1 = 3.3V from the board. Pin 4 = ground. Pin 3 = 3.3V with pull-up resistor from the board. And pin 2 = ground? Basically, I should think of pins 2 and 3 as the pins on a regular push button, right? Thanks for you help by the way, I'm not so great at understanding datasheets yet. \$\endgroup\$ – shanet Jan 22 '17 at 2:10
  • \$\begingroup\$ Nevermind, I got it working. I'll post a full answer below outside of this comment thread. Thank you @Janka! \$\endgroup\$ – shanet Jan 22 '17 at 2:35
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Well, the answer was staring me right in the face on page 8 of the datasheet. When connected as outlined in the schematic below, it works as intended. The only change I made was not using a transistor and replacing R1, R2, and R3 with a single 500Ω resistor.

circuit

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