Timeline for Design challenge: Detect finger-to-finger touch with nothing in between
Current License: CC BY-SA 3.0
7 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Feb 8, 2016 at 22:11 | vote | accept | m4pcy5t0 | ||
| Feb 8, 2016 at 22:11 | |||||
| Jan 19, 2016 at 3:21 | vote | accept | m4pcy5t0 | ||
| Jan 19, 2016 at 3:21 | |||||
| Jan 18, 2016 at 3:25 | comment | added | m4pcy5t0 | Well, the contact will always be poor. I can't use EKG electrodes in the design, it will be rather just something touching the skin but presumably moving, with varying pressure intensity. Therefore I can't rely on small changes in voltage | |
| Jan 18, 2016 at 3:18 | comment | added | Spehro 'speff' Pefhany | It may work, the signal will just be small (perhaps too small to be reliable). I got some 10's of uV change in a crude experiment, but I don't have access to proper EKG electrodes. A 4-electrode arrangement would be much less sensitive to skin resistance. | |
| Jan 18, 2016 at 2:51 | comment | added | m4pcy5t0 | So I've done some research and this won't work. The biggest problem is that a hand works like a parallel circuit and here you expect resistance like in a series circuit. There's always a parallel link between A/B/C. However, this was quite inspiring and your suggestion to use AC was most helpful (so far I've only thought of DC because batteries). AC is supposed to penetrate human body much easier because it's constantly changing. Also, it led me to this new idea: electronics.stackexchange.com/questions/211957/… | |
| Jan 15, 2016 at 0:51 | comment | added | m4pcy5t0 | Wow, that looks impressive, though I have no other idea whether it can actually work :) I'll try to build it and report the results. Thank you for the speedy help, much appreciated! (it will be battery powered, 5V for the prototype, probably 3V in the final product, your safety concerns are spot on and I'm keeping it in mind, I hope it won't be an issue) | |
| Jan 14, 2016 at 23:45 | history | answered | Spehro 'speff' Pefhany | CC BY-SA 3.0 |