[PROBLEM] Problem detecting IR Sensor on GPIO

[John Holmwood]

Software
XBian version: 1.1
XBMC/Kodi version: 14.2
Overclock settings: default

Hardware
Device type and model: Raspberry Pi Model B+
Power supply rating:
SD card size and make/type: 8 GB
Network (Ethernet or wireless): Wireless
Connected devices (TV, USB, network storage, ...): NFS mounted NAS; connected to media centre via HDMI

Log files
Link to logfile(s):

Problem description:
I looked at "IR Prob" in the threads as it seemed to be similar but couldn't see a solution.

I am attempting to add a GPIO IR sensor following:
(http://www.instructables.com/id/Raspberry-Pi-2-Media-Center-Kodi-on-XBian/step6/Step-6-Optional-Install-and-configure-infrared-rem/) Raspberry Pi 2 Media Center: Kodi on XBian

Everything else is working as expected.

However when I try to detect the output from the remote (a UEI DVR-1055) the system doesn't detect anything with either irw or mode2. I placed a LED in series with the sensor output. The led is not very bright but I can see it flicker when I press keys on the remote.

My question is what do I do next? The sensor is working and sending in pulses but the RPi doesn't seem to detect them. How can I troubleshoot the GPIO input?

How to reproduce:
I tried following the troubleshooting steps in:

(http://aron.ws/projects/lirc_rpi/) Raspberry Pi lirc_rpi - (IR Remote control) LIRC GPIO driver

xbian@xbian ~ $ sudo modprobe lirc_rpi debug=1
xbian@xbian ~ $ dmesg | grep lirc
[ 10.496277] lirc_dev: IR Remote Control driver registered, major 247
[ 10.548769] lirc_rpi: module is from the staging directory, the quality is unknown, you have been warned.
[ 11.463637] lirc_rpi: auto-detected active high receiver on GPIO pin 18
[ 11.463956] lirc_rpi lirc_rpi.0: lirc_dev: driver lirc_rpi registered at minor = 0
[ 11.463971] lirc_rpi: driver registered!
[ 16.912180] input: lircd as /devices/virtual/input/input0
[ 50.620376] lirc_rpi: AIEEEE: 0 0 55906714 559066f3 19e7b 8301c

This show the IR sensor is auto-detected on GPIO18 so lirc is running OK

xbian@xbian ~ $ sudo irw
^Cxbian@xbian ~ $ sudo cat /proc/interrupts
CPU0
3: 744615 ARMCTRL BCM2708 Timer Tick
16: 0 ARMCTRL bcm2708_fb dma
24: 258 ARMCTRL DMA IRQ
25: 2004 ARMCTRL DMA IRQ
32: 1183279 ARMCTRL dwc_otg, dwc_otg_pcd, dwc_otg_hcd:usb1
52: 148 ARMCTRL BCM2708 GPIO catchall handler
65: 23 ARMCTRL ARM Mailbox IRQ
66: 37830 ARMCTRL VCHIQ doorbell
75: 1 ARMCTRL
79: 101 ARMCTRL bcm2708_i2c.1
80: 0 ARMCTRL bcm2708_spi.0
84: 8848 ARMCTRL mmc0
188: 148 GPIO lirc_rpi
FIQ: usb_fiq
Err: 0

This shows the interrupt has been set up. Note that irw did not detect any key presses.