SparkFun Serial 7-Segment Serial Display

Ron Czapala · 2011-03-25 18:21

I just got a couple of these four digit, 7-segment LED display modules from SparkFun.

They can be driven by TTL Serial or SPI and come in several colors.

I am using a BS2 at 9600 baud in the video. The characters look whitish in the video, but are actually bright blue. There are commands to set the brightness, change the baud rate and control individual segments and decimal points/colon.

I am really pleased with them!

w4fej · 2011-03-27 08:06

You get 5 stars for entertainment value alone!! PERFECT music for the video!!

Well done!

Mike B.

kwinn · 2011-03-27 10:59

Have to agree with w4fej. 5 stars from me as well.

Ron Czapala · 2011-03-27 18:56

Thanks w4fej & kwinn!

I didn't record any audio so I used the YouTube AudioSwap feature and stumbled on this background music - I don't even recall the name, but it does almost appear like it is synched to the display's "animation"...

CalMariner · 2011-12-09 17:17

Is there any demo code for this?

Ron Czapala · 2011-12-09 18:04

Here is the Basic Stamp code I used in the video - pretty straightforward...

' {$STAMP BS2}
' {$PBASIC 2.5}
DecPts      CON    $77   ' "w" Decimal point command
Brightness  CON    $7A   ' "z" Brightness command 0(bright) - 254(dim)
setBaud     CON    $7F   ' DEL 0=2400, 1=4800, 2=9600, 3=1440, 4=19200, 5=38400, 6=57600
ClearScr    CON    $76   ' "v" clear display and set position to 1st digit
Digit1      CON    $7B   ' "{" set individual segments for digit one
Digit2      CON    $7C   ' "|" set individual segments for digit two
Digit3      CON    $7D   ' "}" set individual segments for digit three
Digit4      CON    $7E   ' "~" set individual segments for digit four
#SELECT $STAMP                          ' Select Baud constants
  #CASE BS2, BS2E, BS2PE
    T1200       CON     813
    T2400       CON     396
    T4800       CON     188
    T9600       CON     84
    T19K2       CON     32
  #CASE BS2SX, BS2P
    T1200       CON     2063
    T2400       CON     1021
    T4800       CON     500
    T9600       CON     240
    T19K2       CON     110
  #CASE BS2PX
    T1200       CON     3313
    T2400       CON     1646
    T4800       CON     813
    T9600       CON     396
    T19K2       CON     188
#ENDSELECT
Inverted        CON     $4000           'Value for inverted serial format
Baud            CON     T9600      '+ Inverted 8,N,1 inverted
LED7 CON 0
'msg DATA "0123456789AbCcDEeFGHhIJLnOoPqrStUuy-'_"
msg DATA "    Scroll test - ABCDEF_0123456789    "
msgend DATA 0
msglen  VAR Byte
msgAddr VAR Word
disp VAR Byte(4)
i    VAR Byte
j    VAR Byte
k    VAR Byte
patt VAR Byte
nxt  VAR Byte
Main:
  msglen = msgend - msg    'calc length of data string
'  DEBUG CLS
  SEROUT LED7,Baud,[ClearScr]
  PAUSE 100
  SEROUT LED7,Baud,[Brightness, 16]   '0]
  PAUSE 100
  patt = 0
  SEROUT LED7,Baud,[Decpts, patt]
DO
  SEROUT LED7,Baud,[ClearScr]
  FOR j= 0 TO 5
    GOSUB Chase
  NEXT
  GOSUB AllChars
  PAUSE 500
  FOR j = 0 TO 3
    GOSUB DecPoints
  NEXT
  PAUSE 500
LOOP
STOP
AllChars:
  msgAddr = msg              'set to start of scroll string
  k = 0
  DO
    FOR i = 0 TO 3
      READ k, nxt
      IF nxt = 0 THEN
        disp(i) = " "
      ELSE
        disp(i) = nxt
        k = k + 1
      ENDIF
    NEXT
    SEROUT LED7,Baud,[disp(0), disp(1), disp(2), disp(3)]
'    DEBUG disp(0), disp(1), disp(2), disp(3), " ", DEC k, CR
    IF k >= msgend THEN
      EXIT
    ELSE
      k = k - 3
      PAUSE 200
    ENDIF
  LOOP
  RETURN
Chase:
  patt = %00000001
  FOR i=0 TO 5
    SEROUT LED7,Baud,[Digit1, patt]
    SEROUT LED7,Baud,[Digit2, patt]
    SEROUT LED7,Baud,[Digit3, patt]
    SEROUT LED7,Baud,[Digit4, patt]
    patt = patt << 1
    PAUSE 80
  NEXT
  RETURN
DecPoints:
  SEROUT LED7,Baud,[Digit1, %01001001]
  SEROUT LED7,Baud,[Digit2, %01000110]
  SEROUT LED7,Baud,[Digit3, %01110000]
  SEROUT LED7,Baud,[Digit4, %01100100]
  patt = %00000001
  FOR i=0 TO 6
    SEROUT LED7,Baud,[Decpts, patt]
'    SEROUT LED7,Baud,[Brightness, (i * 20)]
    patt = patt << 1
    PAUSE 150
  NEXT
  RETURN

Duane Degn · 2011-12-09 18:55

I also like these displays. They're an easy way to add a numeric display to a project.

I modified the object that comes with the Parallax Laser Range Finder to take continuous readings and display the distance (in mm) to the display.

Here's the modified display method:

PRI LRFDisplayRange(range, type)      ' Print the range result
  {
  if (type == cam#ResultBinary)  ' Send 4-byte long in binary corresponding to the actual range value
    ser.Tx(range.BYTE[3])
    ser.Tx(range.BYTE[2])
    ser.Tx(range.BYTE[1])
    ser.Tx(range.BYTE[0])
  else  }                         ' Default to printable ASCII output
    'ser.Tx(NL)
    'ser.Str(String("D = "))
  [B]  if range <> oldRange
      ser.Tx("v")
      ser.Tx("0" + range / 1000)                ' Add leading zeros so we always send a 4-character value
      ser.Tx("0" + (range // 1000) / 100)
      ser.Tx("0" + (range // 100)  / 10)
      ser.Tx("0" + (range // 10))
[/B]   'ser.Str(String(" mm "))
      [B]oldRange := range
[/B]

I had make a couple other modifications to the code. I'm attaching the modified archive.

SparkFun Serial 7-Segment Serial Display

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