Repurposing Virgin Media STB

[hippy]

This is the Virgin Media "V Box", a cable TV unit which finds its way onto the UK second hand market in quite a few places. With 7-seg displays ( decimal points plus colon ), 3 x LED's above 7-seg, Red/Green LED 'power switch', IR receiver, 6 push buttons, plus nice looking IMO, it may be of interest to others who want to hack-a-box to put PICAXE projects in.

Not finished reverse engineering but here's the details so far, and it's looking good ...

Officially the Samsung 2110c.

Lightweight aluminium with plastic front panel. All relatively easy to drill. Raised base should let PCB / vero-board mount nicely without bolt tops scratching surfaces..

Disconnect power, leave to stand to drain capacitors. Take care, don't open the box if not competent. All at your own risk.

The three security screws on the back are a pain to drill out ( not my finest dismantling but no visible damage when on the shelf ). Recommend finding a correct 'screwdriver'. They are Allen key style but with a raised central dimple.

The PSU connects via flying wire 'ribbon cable' can be cut and soldered. Seems to be always on, the "NOT" connection being "not connected" rather than a standby or other signal. So that's likely a nice 3V3, 5V, 5V7 and 12V source. Not sure of current rating though. 0V connects direct to the chassis. Figure-8 two-wire mains input, no earth. There are a number of PSU variants apparently.

Re-use the power supply entirely at your own risk

Front panel connects via 20-way ribbon cable, pull to detach. Socket on front panel PCB looks easy enough to solder flying leads to. Uses 0V and 5V.

The front panel 7-segments controlled by an I2C SAA1064T so that's easy. The LED's driven by transistors, equally easy hopefully - still to find the standby connections. IR receiver across 0V/5V with separate signal connection, again easy. The switches seem to use 74HC164D / 74HC1640 (?) and the circuit there's a bit weird so more work to do. Also a mysterious and minuscule SMT "U4" with no idea what that it is or for.

For rear panel connections, I'd go with screwing some thickish plastic on, mount to that, tin-snip holes where the chassis gets in the way.

More info, pinouts and software examples as it evolves. The aim is to get the whole front panel usable without anything beyond replacing the ribbon cable.

 

[Dippy]

When you say "repurposing" do you mean chopping the guts around and using for something else? Love it.

I just leeerrrv the cool jargon
I'm working in a headsdown office this week. Puke!

What, what , what? Potential mains hazard and no risk assessment? Lordy hipster are you getting daring in your old age? You'll be suggesting 1mW laser projects next

 

[1968neil]

@Hippy,

The PSU connects via flying wire 'ribbon cable' can be cut and soldered.

The PCB connector comes off the board and has the correct pitch for veroboard, quite handy !

1) The remote control is programmable, So the PICAXE Sony IRC can be used.
2) The front LED bezel isnt coloured so the LED displays could be changed to another colour ?
3) The motherboard has two 7805 smt regs on it which could be re-used
4) Regarding the psu, it's a known issue that the capacitors are not of the best quality, so re-capping the psu would be a good idea if to be used with the Picaxe.
5) The smart card socket could be used for a smartcard style programming cable, ie: make a serial prog lead from and old wafer card etc.

Will see if i can scrounge a circuit diagram and then well be able to see what U4 is ?
It's good to recycle ! Maybe you've found a useful purpose for the box ! lol,

Good Luck
Regards
Neil

 

[hippy]

The PCB connector is staggered pitch (0.05") though so not so good with veroboard. Unsoldering the cable socket on the front panel was easyish. Did have one pad fall off later due to too much moving things around but the rest are okay.

The mystery of "U4" is solved, I think. The red/green LED is always one or the other, single control line, so I'd guess it's an inverter.

The display filter is red tinted so replacing the green LED's with yellow, orange or red should work. Will be trying that, and also trying blue.

I still haven't completely worked out how the 74HC164D button multiplex works but have got it working along with everything else. Notes just written and will post them later. A circuit diagram would be handy.

The motherboard is a pain to unsolder. Multi-layer so acts as a heat sinker and probably needs a thermo-nuclear device to loosen things up

The only thing I have managed to recycle from the motherboard is the top half of the SCART by snipping legs and snapping it off. Watch out in removing the aluminium cover as that's sharp and you don't want to slice a thumb and spurt blood everywhere. That would be unprofessional ;-)

 

[hippy]

Front Panel Connector

     .------.                                    O  0V
     |     _|                         (0V)  O
     |    |_                                     O  SDA 7-Seg
     |  __  |                               O
     | |  | |                                    O  SCL 7-Seg
     | |__| |                               O
     |      |                                    O  Btn Common
     |  _   |                               O
     | |_|  |                                    O  Btn Clk
     |      |                               O
   ==| .:   |                                    O  (0V)
   ==| ::   |                      Btn Dat  O
   ==| ::   |                                    O  Right LED
   ==| ::   |                      IR Rcvr  O
     |      |                                    O  Left LED
     `------'                               O
                                                 O  Red/Grn LED
    Viewed from                 Centre LED  O
    solder side                                  O  +5V
                                     (+5V)  O

 

[hippy]

Connector

Remove the flat strip ribbon cable and unsolder the connector. Insert stranded wire ribbon cable or individual core hook-up wire inserted from the component side.

The top of the slot in the main chassis through which the original cable passed can be cut and filed safe to allow the connection to be soldered to any installed board and removed as a complete unit.


Front Panel Power Supply

Requires 0V and +5V. All respective 0V and 5V connections are joined on the front panel PCB. Only one 0V and one +5V needs connecting; recommend using the end connections.


IR Reciever

Standard TSOP18-style reciever, active low, works with IRIN etc. Only 0V, 5V and IR Rcvr needs to be connected to use the IR receiver.

The front panel PCB seems to have supply smoothing and signal conditioning on-board. It seems to work without requiring any pull-up to be added.


7-Segment Display

Controlled by an SAA1064T I2C 7-Segment Driver. Only 0V, 5V, SDA and SCL need to be connected to use the 7-segment display. I2C Device Address is $70, use "HI2cSlave I2cMaster, $70, I2cSlow, I2cByte". Will not work with 'I2cFast'.

The four digits can be controlled individually. Only the centre 'colon' and lower decimal point of that colon can be controlled. Digit 1 is left, digit 4 is right. Top of colon is msb of digit 2. Bottom of colon is msb of digit 4.


Status LED's

There are three LED's above the 7-segment display - Viewed from the front they are Left, Centre and Right, all green. Only 0V, 5V and LED connections needed to make the LED's work.

LED's are controlled by raising the appropriate input high via a ???K resistor.


Power LED

A bi-colour red / green power LED which fits within the 'power switch'. Similar to other LED's except the red LED is always on when the green LED isn't.

Select the green LED by raising the control input high via a ???K resistor.


Buttons

There are six main buttons plus power. These are scanned by a clocked 74HC164D using Btn Dat and Btn Clk. A pull-up to +5V on Btn Common allows which button and button combinations are pushed to be detected

 

[1968neil]

@Hippy,

I've resprayed mine in black, should be ready to re-letraset once dry enough then for some laquer.
Should look nice with the blue led displays i've ordered.
Have you got any further with yours yet ?

Regards

Neil

 

[hippy]

Not done anything further with mine this week but was also thinking of a black spray painting.

I'll dig out the code I've got which controls the 7-seg and reads the buttons.

 

[1968neil]

I'll dig out the code I've got which controls the 7-seg and reads the buttons

Look forward to it !

Regards
Neil

 

[hippy]

A timely reminder ! Both pulled from disk, not re-checked before posting ( should work ).

7-Segment test. May need to power off then on after first download ...

#Picaxe 20X2                          
HI2cSetup I2cMaster, $70, I2cSlow, I2cByte
Hi2cOut $00, ( %00010111 )  ' Set Control Configuration
Do
  b1 = b1 + 1
  b2 = b1
  b3 = b1
  b4 = b1
  Hi2cOut $01, ( b1, b2, b3, b4 )  ' Four digits of '%.GFEDCBA'
  Pause 1000
Loop

Button reading which uses the Weak Pull-Up function on the 20X2-5V B.x pins so no need of an external resistor on the BTN line. Returns a value $E0 to $E8 for a single button held ( it's what I needed for the rest of my code ). It's also possible to build up a bit mask of which buttons are pressed ...

#Picaxe 20X2
#Terminal 9600

Symbol BTN = pinB.5
Symbol DAT =    B.6
Symbol CLK =    B.7

Pullup on
Do
  b0 = 0
  High DAT
  For b1 = $E0 To $EF
    PulsOut CLK,1
    High DAT
    If b1 <= $E8 Then
      If BTN = 1 Then
        b0 = b1
      End If
      Low DAT
    End If
  Next
  SerTxd( #b0, " " )
  Pause 1000
Loop

 

[MPep]

Hippy,
What exactly are you re-purposing the set-top box for?
MPep.

 

[hippy]

Primarily for the PICAXE + MP3 Module ...

http://www.picaxeforum.co.uk/showthread.php?t=16353

It's not a perfect box but the closest I've found which is reasonably easily attainable with 7-seg and some buttons which is always handy no matter what the project. Well, certainly for any I usually think of. I reckon the 7-seg + button section could also be sawn to fit a VFD or LCD.

 

[1968neil]

@ Hippy,

looking good, tried the code in the simulator, havent got any 20X2 chips, i'll get some on order now.
Have been thinking along the lines of using an LCD, will have a look at that over the weekend.

The I/C U4 is a simple led controller, tried to get a circuit but alas no joy, was told even Virgin aren't privvy to that info and as you can imagine Samsung where of no help, they said "try Virgin".
The power connector on mine fits vero very well, wonder if yours has a different motherboard variation ?


Regards
Neil

 

[hippy]

Yes power connector would fit, 0.1" pitch - thought you meant the front panel ribbon cable !