Yes, sometimes it can be a little tricky to get the IR configuration right. We have a high confidence in our IR blaster hardware. In soak testing we have sent 1000000 presses through them without a single missed keypress†.
This leaves three general causes of IR unreliability (in order of which you should check first):
Bad positioning of the IR blaster over the IR receiver
The stb-tester ONE’s IR transmitter is a low-power transmitter (to avoid interfering with other set-top boxes in your test lab) so it has to be close against the set-top box’s IR receiver.
Some set-top boxes are very sensitive to the placement of the transmitter; for example this set-top box has a cylindrical shield extending around the IR receiver diode, so the stb-tester ONE’s IR transmitter must be placed precisely in front of the diode:
Using a torch (flashlight) can help you to see the position of the IR receiver behind the set-top box’s plastic case.
Bad lircd.conf IR configuration
You could try fiddling with the timing information at the top of the lircd.conf infrared configuration file. We have a blog post where we describe how lirc works and there is reference documentation on each lirc directive as well.
That said, the easiest thing to do here is add a min_repeat 3 directive to your lirc config file and that will often fix issues you've been having. This goes in your config/remote-controls/xxx.lircd.conf somewhere between begin remote and begin codes.
Example: your config/remote-control/my-remote.lircd.conf config file will look like:
begin remote
name MY_REMOTE_CONTROL
bits 8
frequency 35555
...
begin codes
...
end codes
end remote
and you add min_repeat 3 underneath frequency. So the config file now looks like:
begin remote
name MY_REMOTE_CONTROL
bits 8
frequency 35555
min_repeat 3
...
begin codes
...
end codes
end remote
This will cause stb-tester to send the IR signal 3 times each time you call press() from your test-script. Your set-top box should interpret this as a single press, as if the user held the button down fractionally longer than usual.
You may find that your set-top box is now performing two presses sometimes instead of one. In that case change it to min_repeat 2 instead.
Bad IR receiver hardware/software (in the set-top box)
We have seen some set-top boxes don't always react when you send them a keypress due to hardware problems or software problems. A symptom of this is that the set-top box will sometimes ignore real presses from a real remote control. There are two things you can do in this instance:
Fix your set-top box - if you are the set-top box manufacturer you may be able to lean on your dev team/hardware designers to fix the software/hardware in the set-top box so it doesn't have this issue. This will be good for the end-users of the set-top box too :)
Work around it in your test-scripts - it's a good idea to check that performing an action in your test-scripts had the desired result anyway, so you can add logic to retry presses if there was no effect. Using APIs like press_until_match will naturally mask these issues.
This is a last resort however as it can reduce the readability of your test-scripts and increase the maintenance cost.
† Our gen 1 IR blasters had reliability issues (0-0.5% failure rate per press), but we replaced them all in May 2016 sending our reliable gen 2 hardware out to all our customers. You can read about our investigation and how we fixed it in our IR blaster gen 1 post-mortem blog post.
Disclaimer: I work on stb-tester and am an employee of stb-tester.com Ltd.
