New "Bubble" display!

Member LarryD turned me on to these little displays from Sparkfun, little bubble display 4 7-segments displays.
He uses them in a pulse counter box he makes.
Taking 2 and mating them with a MAX7219 from Tayda electronics, and a couple parts makes up this little board.
I bought material for 50 cards, LarryD is buying 30 35 already!
So 2015 are available, $12.85 each plus shipping; I think a kit in padded envelope shouldn’t be too much, will find out next week.
If there’s interest, I can get more until Sparkrun runs out of displays.
The 10uF can be mounted flatter, or on the back.
The holes for the display have double rows to accommodate a right angle socket, 2 of mouser 575-2994331211,
and put the display at right angle to mount the board behind a panel. Pricey tho, $7.61 for a pair when purchased in 10-lots.
Wirewrap socket can be bent up also, I’ll leave that to the user.

"Description: This is the HP QDSP-6064 bubble display, a tiny, 4-digit, 7-segment numerical indicator. This little guy is perfect if you need some user feedback from your system, but don’t want to fiddle with LCDs or other display options. The Bubble Display comes in an easy-to-use 12-pin DIP package and can be used in breadboards, protoboards, or PCBs.

These bubble displays have a peak forward current per segment of 5mA at a peak forward voltage of 2V. Thanks to a neat magnification technique used by the QDSP-6064 (giving it the “bubble” name), the luminosity is intensified making lower power consumption possible."
I’m running with a 10K Iset resistor and intensity set to 6, seems to work pretty well.

//Bubblelicious  test
#include <SPI.h>

byte ssPin = 10;

byte fontArray[] = {
  // dp-a-b-c-d-e-f-g
  0b01111110, // 0
  0b00110000, // 1
  0b01101101, // 2
  0b01111001, // 3
  0b00110011, // 4
  0b01101101, // 5
  0b01101111, // 6
  0b01110000, // 7
  0b01111111, // 8
  0b01111011, // 9
  0b01110111, // 10 A
  0b00111101, // 11 d
  0b01001111, // 12 E
  0b00110111, // 13 H
  0b00010000, // 14 i
  0b00001110, // 15 L
  0b00010101, // 16 n
  0b00000101, // 17 r
  0b00011100, // 18 u
  0b00011101, // 19 o
  0b00000000, // 20 blank

byte messageArray[] = {
  13,12,15,15, 0,20, 4,20, // HELLO 4
  10,17,11,18,14,16,19,20, // Arduino

byte Noop = 0x00;
byte decodeReg = 0x09; 
byte normalReg = 0x0c;
byte displayReg = 0x0f; 
byte scanReg = 0x0b;
byte intensityReg = 0x0a;

byte digits[] = {
0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08,};

byte x;

void setup(){
  digitalWrite (ssPin, LOW);
  SPI.transfer (intensityReg);
  SPI.transfer (0x06);
  digitalWrite (ssPin, HIGH);
  digitalWrite (ssPin, LOW);
  SPI.transfer (decodeReg);
  SPI.transfer (0x00); // no decode for all digits
  digitalWrite (ssPin, HIGH);
  digitalWrite (ssPin, LOW);
  SPI.transfer (scanReg);
  SPI.transfer (0x07); // all 7 digits
  digitalWrite (ssPin, HIGH);

  digitalWrite (ssPin, LOW);
  SPI.transfer (displayReg);
  SPI.transfer (0x00); // normal operation
  digitalWrite (ssPin, HIGH);  
    digitalWrite (ssPin, LOW);
  SPI.transfer (normalReg);
  SPI.transfer (0x01); // normal mode
  digitalWrite (ssPin, HIGH);
void loop(){
  for (x=0; x<8; x=x+1){
    digitalWrite (ssPin, LOW);
    //SPI.transfer (0x01);
    SPI.transfer (fontArray[messageArray[x]]);
    digitalWrite (ssPin, HIGH);
  delay (750);
  for (x=0; x<8; x=x+1){
    digitalWrite (ssPin, LOW);
    SPI.transfer (fontArray[messageArray[x+8]]);
    digitalWrite (ssPin, HIGH);
  delay (750);  

And daisychain-able 8)

How's that No-op thing work to send multiple groups of 8 out?

No he is wrong. I don't want 30, I want 35 (if he lets me).

These will be great as a very small foot print 8 digit panel mount displays. See:


I've had four of these displays sat on my desk for a couple of months just crying out to be used for something! Pretty cool be they.

Here is an image to front panel mounting of the displays.

I wonder what the comparative cost between that method and something like this is:

To me, it comes down to the things I have right now, on hand. I have used both equally well.

I like that the dimensions of the 8 digit display are only 1.25" by 0.3" with only 5 wires !

@Tom Carpenter, Need the 24 pin version.

Best I could come up with was using two 12-pin sockets made by MillMax and sold by mouser. If purchased in 10-lots (five board's worth) could be had for $7.62 a board. I wasn't going to add that to the kit cost. That's more than the displays themselves.

Even though the display pins are relatively long, I like the idea of using Wire Wrap sockets as they can be mounted on the outside of a front panel. Socket pins are long enough to go through the thickest plastic panel. With the female header idea, you can simply unplug the PCB from the socket pins if needed.

CrossRoads: @Tom Carpenter, Need the 24 pin version.

Ahh yes, of course. For a moment there I though each display had 10 pins!

They do seem a bit expensive.

Anyone ever find a display like this, but a 14/16 segment display? Now that would be cool.

I got about 30 of these off of eBay a while back from a guy and I think I paid about a buck a display, a couple of years ago. Now there are none for sale. My date codes are from '99. Are these still being manufactured? What are your date codes?

You can pickup 4 of these displays, make a double board like the one in the attached image, then you can have a 16 digit display with 2 of Bobs Bubble-Licious boards

Actually all you need to do is get two of Crossroads boards as they come with the displays.

1,949 still available

Code is V9908

Yes, 1999 apparently. When gone, will likely be gone.

CrossRoads: Yes, 1999 apparently. When gone, will likely be gone.

Must have been one last manufacturing, a lot of them sat in inventory for a decade, and then got blown out. They are cool little displays.

There is some very interesting history that goes with the "bubble" led's.

They were originally developed by Hewlett-Packard for use in their revolutionary (at that time) scientific pocket calculator, the HP35. The 35 was the first hand held device that could perform transcendental functions and it introduced a unique entry method known as Reverse Polish Notation or RPN as it became known.

HP developed and manufactured their own displays because the available displays of the era consumed too much current for HP's liking, knowing it would significantly reduce battery life. They went even further in the quest to improve battery life by multiplexing the displays and energizing the segments one at a time with relatively high current pulse that was delivered from an inductor connected to each of the seven segments. They used a different value inductor for the decimal point so that it matched the intensity of the other segments as seen by the human eye. This was such a unique approach to controlling the brightness that HP eventually patented it. A copy can be found here:

You can read more about the development of the HP35 at the link below, discussion about the display is on page 7. The narrative was written by the principal developer, David Cochran.

If ever owned an HP calculator, you might want to visit this site as well:

Just got my Bubble-Licious cards.
They look and work great.
Can't wait to get them in some projects.
Sparkfun bubble displays down to 1,727 that is -100 per day.

I finalized the vertical mounting by using two 12 pin right angled female headers ($1.00) and one 24 pin wire wrap socket ($1.00).

I used a piece of old 1/16" PCB material to raise both female headers off the Bubble-Licious surfaces to get the 0.3" spacing needed for the wire wrap socket.

Thanks Crossroads.



LarryD: Sparkfun bubble displays down to 1,727 that is -100 per day.

Rumor has it that Crossroads is trying to corner the market... :grin:

Heh, heh, yes the DisplayMaster 8)

Larry, you've found several clever ways to mount the displays to cards!

I think others have discovered these bubble displays and know they are a one time offer. They are getting them before they are all gone.

The bubble-Licious board makes them almost plug and play.