Improving TX3 Pro Amlogic S905X Android box's IR remote sensitivity

TX3 Pro is a decent and affordable Android box based on Amlogic S905X.  Unlike many other cheap Android boxes, this box does have an window for the IR receiver.  Its IR sensitivity turned out to be indeed better than Tronsmart S95 Pro's, which is horrible due to the poor IR transmission of the body and lack of IR receiving window (you can drill a hole and replace the receiver with a decent one).  However, it is still not as good as I expected.  For example, it cannot detect IR reflection from the ceiling, which decent IR receivers with a proper window can handle.

I tried to align the IR receiver with the window as much as possible, but no noticeable improvement was seen.  So, I replaced the IR receiver with Vishay TSOP34438, which is pin compatible with the original. The legs of the receiver need to be bent so the receiving dome touches the IR window when the board is mounted on the case.  Now I can point the remote at the ceiling and the box still recognizes the signal with no problem - SUCCESS.

By the way, the IR remote control can be easily customized by editing /system/etc/remote.conf which has a mapping table from IR code to Linux key code (not Android key code!).  Here is a nice Linux key code table along with Android key code.  If remote.conf keeps being overwritten by the default one at reboot, make it readonly with chmod so it won't be overwritten.

IR window

Motherboard with the new IR receiver

New IR receiver

 

Original IR receiver

HAP-Z1ES PCM1795 Register Settings

I measured the serial configuration interface of the PCM1795.  The following register settings were found in the DSD mode (for both DSD source and DSD remastering).  DMF[1:0] = Reg18[4:3] = 01, so DSD Filter-2 is used for the analog FIR.  In addition to the on-chip FIR filtering, there is additional first-order FIR filtering (1+z^{-1}) realized by connecting two current outputs together with one input delayed by one sample.  

Reg16 = 0xff
Reg17 = 0xff
Reg18 = 0x54
Reg19 = 0x00
Reg20 = 0x20
Reg21 = 0x00
Reg22 = 0x00
Reg23 = 0x00

Slingbox 350 teardown

I'm glad that the infamous G-Luxon electrolytic capacitors are no longer used in these new Slingboxes.  The video decoder chip below the third RCA connector from the right is Analog Devices ADV7181C, which does not claim to support 1080p.

Boeing 777-style CPDLC/ACARS chime

I couldn't find any clean Boeing 777-style CPDLC/ACARS chime on the web, so I tried making one with Matlab.  What I made is a 0.49-s 1150-Hz sinusoide followed by a 0.60-s 580-Hz sinusoid with some amplitude modulation.  This is pretty much a D-D with one octave separation.  I am not sure about the fidelity of the sound but it shouldn't be too bad.

acars.wav

For iPhone email notification:
new-mail.caf

A = 0.25;

T1 = 0.49;
T2 = 0.60;

Tr1 = 0.04;
Tr2 = 0.04;

f1 = 1150;
f2 = 580;

fs = 44100;

t1 = 0:1/fs:T1;
t2 = 0:1/fs:T2;

% base
y1 = A * sin(2*pi*f1*t1);
y2 = A * sin(2*pi*f2*t2);

% Envelope
k1 = 1:round(fs*Tr1);
k2 = round(fs*Tr1)+1:round(fs*T1);

y1(k1) = y1(k1) .* fliplr(sqrt(1-(k1/k1(end)).^2));
y1(k2) = y1(k2).* fliplr(k2-k2(1))/length(k2);

k1 = 1:round(fs*Tr2);
k2 = round(fs*Tr2)+1:round(fs*T2);

y2(k1) = y2(k1) .* fliplr(sqrt(1-(k1/k1(end)).^2));
y2(k2) = y2(k2).* fliplr(k2-k2(1))/length(k2);

% Concatenate
y = [y1 y2];

sound(y, fs);

DELL U3011 gamma correction curve

AdobeRGB mode

sRGB mode

These were measured with Cormunki.  Both look quite off.  Is it the monitor or Colormunki that's off?  Either way, this monitor is a lot better than the 7-year old Benq PVA monitor I have been using both in size and quality. Now I can watch TV from my armchair and bed.

Toshiba D-TR1 now supported by Sling Media

Sling Media has added loads of remotes for the new Japanese market.  Now Toshiba D-TR1 is officially supported but the skin is a generic one with a lot of tiny unused buttons and some buttons are missing.  I will keep using my skin.

Sling Media's Toshiba remote skin (left), my D-TR1 skin (middle), my shorter D-TR1 skin (right)

The skin I made is a bit too big, but shrinking the size takes a quite a bit of work so I rather live with this one.

WebSlingPlayer picture quality in regular SlingPlayer

WebSlingPlayer renders much smoother pictures than the regular SlingPlayer.  The difference is particularly apparent for sharp features as shown below (click on the image to see the pixel-by-pixel image).

I tried copying some files from the WebSlingPlayer program directory to the SlingPlayer directory to see if it is possible to have the WebSlingPlayer picture quality in the regular SlingPlayer since I do not like the WebSlingPlayer.  It turned out that copying SBDS.ax and H264DecoderDLL.ax works.  Here are the versions of the players I tried:

SlingPlayer: 2.0.4.522
WebSlingPlayer (IE8): 1.4.0.111
OS: Windows 7 Professional

I tried the same with my netbook running Windows XP, but the method above didn't work for some reasons.