Hi,
I'm working on a project dubbed 'touch tokens'. The goal is to create small electronic devices that you can place on a capacitive touch screen, that will 'communicate' their position on the screen and their 'identity', by the frequency at which they touch the screen. This is the current prototype I've got working:
http://www.youtube.com/watch?v=2-3MjeL1Szc
The circuit consists of a CMOS 555 in astable mode that switches a 4066. The 4066 switches a wire running from the touchscreen to one of the phone's dock connector ports.
The next stage in the project is moving the whole circuit onto the phone's screen, so I want to reduce the number of components as much as possible.
I switched from a normal NE555 to CMOS 555 already, to save power. The datasheets said I could remove the decoupling capacitor across Vdd and ground, so I did. I was wondering if for this purpose, can I also safely get rid of the bypass cap across the Voltage control (pin 5) and ground?
The 4066 is also too large for my goals, so I was planning to substitute that for a smaller single switch analog switch in DIP-8 package. Do you know any that are cheap like the 4066 and do the same thing?
Finally my biggest concern is this mandatory connection to the phone's dock connector. The phone's metal side ring also works fine, but ideally I want these things to be unconnected at all. Common sense tells me that's not possible, but maybe you know of some things I could try?
Thanks a lot!
I'm working on a project dubbed 'touch tokens'. The goal is to create small electronic devices that you can place on a capacitive touch screen, that will 'communicate' their position on the screen and their 'identity', by the frequency at which they touch the screen. This is the current prototype I've got working:
http://www.youtube.com/watch?v=2-3MjeL1Szc
The circuit consists of a CMOS 555 in astable mode that switches a 4066. The 4066 switches a wire running from the touchscreen to one of the phone's dock connector ports.
The next stage in the project is moving the whole circuit onto the phone's screen, so I want to reduce the number of components as much as possible.
I switched from a normal NE555 to CMOS 555 already, to save power. The datasheets said I could remove the decoupling capacitor across Vdd and ground, so I did. I was wondering if for this purpose, can I also safely get rid of the bypass cap across the Voltage control (pin 5) and ground?
The 4066 is also too large for my goals, so I was planning to substitute that for a smaller single switch analog switch in DIP-8 package. Do you know any that are cheap like the 4066 and do the same thing?
Finally my biggest concern is this mandatory connection to the phone's dock connector. The phone's metal side ring also works fine, but ideally I want these things to be unconnected at all. Common sense tells me that's not possible, but maybe you know of some things I could try?
Thanks a lot!