# How do I connect this piece of electronics to show the digit display? (from satellite decoder)

I have the following piece of board/electronics:

Now, I recently bought an arduino, so I want to connect the digit display to show digits,

I already have blown out an IR receiver so that's the reason I disassembled an old satellite decoder, and I pulled the IR receiver out from this.

But now I am curious, I cannot find any datasheets for this (maybe they are closed source?).

I am wondering how I can connect this to work with an Arduino?

• Interesting. The display has its own dedicated ATTINY2313 MCU, but the buttons have direct wires back to the main board. Given the SCL and SDA test points, it would seem that the main board communicates with the display via I2C, which actually complicates matters. Directly driving the display would be easier to explain. Mar 7, 2014 at 21:39
• In the vein of what @DaveTweed said. The 7-segment characters are driven from that μC and commands are sent to it via I2C. The communication protocol is unknown, because the board is salvaged from a piece of consumer electronics. Mar 7, 2014 at 22:16
• OTOH, you could probably reprogram it with this code after making some changes to it. Mar 7, 2014 at 23:09

In my experience, the pinout for LED displays of a given configuration and number of pins almost always conforms to defacto industry standards. Here is a similar display available through distribution that I expect would have the same pinout.

Edit: David Tweed has noted the display is Common Anode, so the below schematic should be correct. The digit-drive transistors appear to be NPN emitter followers. You could retain those and the segment resistors to drive the display from another micro (total 11 lines required).

This assumes you're going to strip out the display and drive it directly. If you want to continue to use the micro on the board, the protocol is probably not going to be easy to reverse engineer, even if both halves were working.

• Oh, it's clearly common-anode, since the digit-drive transistors on the back are tied to +5V. Mar 7, 2014 at 21:44
• @SpehroPefhany I disagree that the pinout of 7-segment characters is "pretty much standardized". Look at Avago HDSP-523E. Besides, posting a link to a single product by a single vendor is not enough to demonstrate that there is a de fact standard. Come one, step up your game. Mar 7, 2014 at 22:29
• Your Avago display has 18 pins not 16 pins, obviously it's a different "industry standard". Mar 7, 2014 at 22:41
• @NickAlexeev On reflection, I was too economical with words and it may have appeared the link was to justify the statement about industry standards. It was not intended as such, and I've restated it as an experience-based statement and a separate link. Mar 7, 2014 at 23:05
• reverse engineering is indeed a big pain, I do have the main board,so wouldn't it be maybe possible to connect te arduino for a man-in-the-middle reverse engineer attack?:P Mar 8, 2014 at 11:22