Proxmark3 community

uberdude

Contributor

Registered: 2011-05-24

Posts: 17

Portable consumer electronics Proxmark3

I wanted to build a PM3 that had a nice 'comsumer electronics feel too it. Basically, if the TSA pulled my PM3 out  at an airport, they wouldn't initiate a strip search on me.

Here is the final result:

I used the LiPower board from sparkfun to convert the battery voltage to 5 volts and then soldered its output to the  PM3. As you can see, I desoldered the huge socket to free up some real estate. It also made a handy place to attach the ground using one of the pins (#4). I picked the #3 empty pad from Q2 which, contrary to the schematic is not populated but R56 is. Odd that the PM3 is different from the  schematic and not sure why the MOSFET was omitted, but it made for a handy place to solder in power. The pad is just downstream from the U1, the ferrite bead. I was concerned that the LiPower's max ripple of 15mV at 135kHz would cause too much EMI. Everything seems to be working fine, and as near as I can tell, there is no adverse effect on the read range.

The battery is a 900mAH battery also from sparkfun. I wrapped the battery in a sticker from an old cell phone battery that has an LG electronics logo hologram, to further enhance the 'consumer electronics' feel. Based on earlier measurement, I'd estimate that the battery will last 8-9 hours. The PM3 draws approximately 100mA.

I also built my own LF antenna since I'm going to use this in its HID standalone mode (Thanks Samy!). The antenna is fairly bulky and caused a bit of misalignment of the enclosure, but it still works fine. If there was a good HF standalone mode, I could easily make an HF antenna fit under the board.

Oddly, I had my LF antenna *perfectly* tuned to 125kHz (40 V), but was unable to pick up a HID ProxKey. The ProxCard worked great, but not the keyfob. The datasheet  for the ProxKey clearly states that its a 125kHz device, but only when I detuned the antenna to ~129kHz was I able to pick up the ProxKey. Not sure what is going on, unless the ProxKeys are detuned because of their small size.

borjaburgos

Contributor

From: New York, New York

Registered: 2011-07-05

Posts: 38

Re: Portable consumer electronics Proxmark3

Great job! I was wondering, did you buy your proxmark3 with a case or where you able to get it separately? I'd love to get a case like that for my proxmark.

Did the battery end up lasting as much as you had estimated?

uberdude

Contributor

Registered: 2011-05-24

Posts: 17

Re: Portable consumer electronics Proxmark3

I got the case from http://proxmark3.com/

I haven't done a battery capacity test, but I based my estimate on the amp draw over a USB cable, so I'm pretty sure its accurate.