Typically the x-series glass tube types of implants require you to place the implant perpendicularly across the trace of the reader antenna. Flex implants like payment conversions usually need to be placed parallel to the traces of the reader antenna. You can usually assume the antenna path in most payment terminals as being around the LCD screen, or if the contactless area is defined as some other area, it’s usually a square or rectangle antenna shape under the defined area. From this you can pretty easily determine the best placement.
Sometimes, for flex implants, the best reads are actually at a 45 degree angle that lay across the corner of one of these rectangular reader antennas.
Slowly moving your hand can work sometimes, but it can also result in a chip “browning out”. Just like a power brown-out, a chip can enter an unstable operational state because as you get closer to a good coupling, it can get just enough power to begin operating, but not enough power to perform any communication or perform any complex calculations or data access operations. This results in too little current being supplied to the chip and it kind of … bugs out … for lack of a better term.
A better approach in these scenarios is to remove the chip from the field, then tap straight down to the target area… wait a half a second for a read… then remove, and tap in a slightly new spot.
that was super helpful as i do have difficulty visulising what the workings of the NFC reader actually are. so basically they’re jsut a look of wire possibly around the screen. i was thinking it was a descrete spot perhaps in the middle of the screen as that tends to be where i put my card when paying - slap bang in the middle of the screen. so with the implant i need to be aiming for perhaps the top or side of the screen depending on the orientation of my implant?