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Author Topic: switching out pushbuttons with touchpads  (Read 3665 times)

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ninjay

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switching out pushbuttons with touchpads
« on: October 07, 2011, 18:52:43 PM »
hey everyone! this is my first project on this forum. i like to make and mod arcade style controllers for consoles (ps3, 360) and pc.  i used to have to take the PCB out of controllers to use, but people are starting to make their own PCBs that work for all consoles. the buttons and joystick work on microswitches, so i figure i can use a capacitive touch pad as a microswitch.

these are the microswitches found on some buttons and sticks:
http://www.canonspike.com/Canon_Spike!/Joystick_Mods/Entries/2009/3/24_Hori_EX2_Cherry_Switches_+_Octogate_quick_mod_files/cherry%20mod.jpg


this is the PCB i will be using. it is called a Cthulhu and it works for PS3 and PC
http://www.arcadepower.ca/images/cthulhu-diagram.jpg

the only thing that i know how to do is to solder, so this is going to be a fun learning experience for me.

first off, i need a shopping list.  i have seen in the 10 button PIC pad tutorial that the panels are all together on one board. i am planning on doing the same thing and then i need to wire the signal for the button press and ground to the Cthulhu.  i will also plan to add an led to light up the panel i am touching. 

what material do i need to get this project started? right now i have a bread board and a bunch of 22awg wire. thank you for all of your help.


kam

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Re: switching out pushbuttons with touchpads
« Reply #1 on: October 07, 2011, 23:41:22 PM »
for the capacitance you can find everything on the article. there is a bill of materials at the bottom, but if you have not with capacitance before i must war you that designing a capacitive PCB is hard and needs experience. Moreover it is absolutely improper for game controls because it lacks the tacktile feeling.  suggest you use classic arcade buttons.
Now, if you want to go with capacitance, the one i've designed has a BCD output:
0000
0001
0010
0011
0100
and so on. So you will need a BCD to decimal decoder (74ls42 will do) and then you need something to interface the decoder to your board. I suggest you use transistor switches. One transistor per channel (button) so you need 10 transistors, some resistors, some capacitors...

ninjay

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Re: switching out pushbuttons with touchpads
« Reply #2 on: October 08, 2011, 00:04:48 AM »
i see that there is the PIC16F1937-I/P on the PCB. what is the differences between the I/ML, I/P, and I/PT?  since it is 14 channels, does that mean i can have up to 14 different buttons?  also, on the PCB that i am using for the controller has a place for 5V power. will that be enough or do i need to add on some batteries?

kam

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Re: switching out pushbuttons with touchpads
« Reply #3 on: October 08, 2011, 00:28:25 AM »
the I/P staff is for the packaging, temperature etc, no need to worry about. It has 16 channels which means that you can have at least 16 buttons (more if you multiplex). 5Volts is excellent for this PIC.

ninjay

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Re: switching out pushbuttons with touchpads
« Reply #4 on: October 08, 2011, 01:49:18 AM »
http://projects.dimension-x.net/archives/111 here is another video i found that uses a qprox qt160 ic. is this chip the same as the one you advised me to use?

kam

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Re: switching out pushbuttons with touchpads
« Reply #5 on: October 08, 2011, 11:02:14 AM »
qt160 is a capacitance touch sensor. no this is not the chip i suggest. i suggest a simple ttl chip to do the interface.

ninjay

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Re: switching out pushbuttons with touchpads
« Reply #6 on: October 08, 2011, 22:49:09 PM »
on the picture you have for 16F1937 for the 10 button pad, are the circle with x's indicate the channel you are using for the buttons? which pins are the other 6 channels?

ninjay

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Re: switching out pushbuttons with touchpads
« Reply #7 on: October 08, 2011, 23:31:50 PM »
would it be easier if i used one of those atmel qt ics?

kam

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Re: switching out pushbuttons with touchpads
« Reply #8 on: October 09, 2011, 10:37:04 AM »
of course it would be easier with the qt if you do not know about PIC.

ninjay

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Re: switching out pushbuttons with touchpads
« Reply #9 on: October 11, 2011, 21:18:25 PM »
would you be willing to program a chip for me? i will pay you for your services and shipping of course. i need 14 channels that will only be used as a signal to the arcade pcb when touched.