hi all, this is my very 1st post here..
i been into electronics since i was a kid.. much that i have learned as a kid and much is self taught.. i have no formal electronics training.. i been repairing TV's / amps ( mostly consumer electronics ) i been in the arcade field for many years also repairing. rebuilding games / pinball repair etc. and now i work for the city traffic signal system for over 14 yrs now..
ok, enough about me.. i just wanted to show i am not a newbie in electronics.. but i am a noob when it comes to programming.
almost clueless, no night time classes around here for such stuff ( sad )
anyway i have saved / salvaged some of the pedestrian signal modules that have the count down timers in them.
typically 8" tall digits. i want to use these large digits and build me a large GPS controlled clock that can flash the time and date.
i have seen smaller ones here, but they do not fit my purpose.. so with me doing some research , i have come up with what i think may work for hardware, but i need guidance and suggestions.. i'll defiantly need code help.
here is what i was thinking to use for hardware..
a gps unit + arduino ( mini or nano ) + Maxim MAX7219 ( display driver ) total of 6-digits will be used.
i think this might be as simple as i can get. any better suggestions ?
the displays i have require about 9V per segment, and draw about 40-60ma .. some segments have a few more leds than others. The displays are also common anode.. i do have some other displays,, same size, but they require about 12V and are common cathode, but i do not have enough displays yet.
thanks for reading, and i appreciate any help that is offered,, i am dead set on making this, and i'll share it to all when i am finished, and give credit to those that help me
thanks :o)
This card uses TPIC6B595 shift registers, which are high current/high voltage parts.
http://www.crossroadsfencing.com/BobuinoRev17/
Wire each shift register to a digit, shift in a 1 for each segment you want turned on.
No MAX7219 needed.
Has Arduino functionality built in, so you only need to connect to GSP to get the time, then shift out the data to make it display on the common anode digits.
You'll need a current limit resistor per segment if they are not part of the digits already.
thanks for the tip.. i am looking at the board, and i see that it will drive 12 digits,,i will only be needing 6 digits..
i do not see a price for the board,,do you know it ?
also do you know if the board has the option to use either common cathode or common anode displays ?
thanks...
Fully populated, assembled board is ($100, +5.25 shipping) + 2.39% paypal fee.
With just 6 shift registers, $95 + shipping + fee.
TPIC6B595 sinks current only, so common anode displays. Current limit resistor per segment will be needed if not built into the segment/display already (not very common tho).
do you know if the board is available as a kit ?
Yes, I also sell it as a kit. $50 plus shipping & paypal fee.
oh great..did not know it was you selling them.. cool..
how do i go about ordering the kit for the 6 digit unit ( kit )
i do have paypal.
Send money, I'll pull one together, could probably mail it tomorrow afternoon.
(50 + 5.25) + 2.39% = $56.35 to cardinalflyer at comcast dot net
thanks, i just sent you the payment..
one more question.. i saw on the schematic for this that there is a jumper selector for the display power 5V and ??V
i am guessing it is what ever power from power supply before it goes into the 5V regulator ?
the displays i have use 9V.. is this what the jumper is for? select between input power and regulated power (5V)
The jumper lets you select which voltage goes to the V+ pin on the 9-pin header for the common anode display; Vin or +5 from the regulator. Or you can leave off and connect the common anodes together at the display and connect right to your 9V source.
Did you want a barrel jack, or a 2-screw terminal for the power connector?
Will put together a kit when I get home, send out tomorrow. MrsCrossRoads (the wife) indicated yesteray we were getting low on 24 pin sockets, so I ordered more. Worst case you might have to wait a few days until they come in.
barrel jack will be fine 
i am going to get started on getting my displays mounted and wire prepped..your board will help speed things along for me a lot faster..
i tried to find the board that "sparksfun" used on his Giant Green Clock" but it seems to be out of production. the site says it is not available any more.
i started / finished assembling the board last night.. i think i have it ready to start implementing things..
get everything mocked up and how i plan to wire things up etc.. i'll post my progress here..
curious about the board..as far as the way the IC locations are labeled the numbers are not in any order..
i wonder the logic behind it..
Numbers came from how the schematic was created, nothing more.
Last byte shifted out ends up at lower left, then across to the right,, across the middle right to left, then across the top left to right.
If you send out bytes 0 to 11 in order with 0 first, they go to:
3-2-1-0
4-5-6-7
11-10-9-8
Makes data flow nice, while SCK, SS, and OE. get fanned out to all chips.
If you're not going to use PWM, be sure to make Pin 9 low.
ok, i got a question.. i think i have the digits wired up to the driver board ok,,in the right order i hope..
the question is..
how difficult would it be to whip up a simple test to make sure i have all the digits wired up correctly (in the right order) ?
right now i have the digits wired up as....
( 10hr on IC 2 & 1hr on IC 3 ) - (10 Min on IC 6 & 1 Min on IC 8) - (10 sec on IC 5 & 1 sec on IC 10)
as for the Colons i will probably drive them from pin 17 - DP from IC 2
does this sound right so far ?
thanks.
Write simple SPI.transfer loop,
for (x=0; x<12; x=x+1){
SPI.transfer(dataArray[x]);
}
byte dataArray[] = {0b01000000,0,0,0,0,0,0,0,0,0,0,0,}; // turn on G of 1 digit
0b00100000 F
0b00010000 E
0b00001000 D
0b00000100 C
0b00000010 B
0b00000001 A
Manipulate data to track what you want.
ok, thanks.. now i have something to play with and learn..
right now i started wiring up the led digits..i had to modify them.
i'll keep you posted.. thanks..
hi there..
i been working on my clock as i have had time ..
i got another question.. on the board the FTDI connection has the pins TX , RX
( do i connect RX to RX and TX to TX, or do they cross over ? )
is this the same pins i should use to connect my GPS to ? or should it be connected elsewhere ?
my assumption is use the FTDI port to load the program on. then disconnect the FTDI and connect the GPS.
i have my 1st display 10hr digit connected to IC 2 and the last digit 1's second connected to IC 10.
everything is mocked up, and wired up for testing..
oh ya, other question. as far as loading programs , do i use the arduino program or something else ?
thanks for your patience with me :o)
hi there, sorry it's been so long since i got back on here,, life you know...
anyway i wanted to finally share some pics of the GPS clock project.
it's finally done, works well. may have some different features later on like dimming.
i tried the PWM dimming, but the leds were singing and that annoyed me, so i'll probable
use a regulator and foto cell circuit to change voltage that controls the display.
anyway see attached pic.. ( i hope i can remember how to post them. )
