MAX7219 to run 7 segments displays

[patogn20]

Hi all!!

 

I'm THIS close to finish my Huey cockpit. It runs completely on DCS Bios. The only thing that is missing are the comms displays. The idea is to give the cockpit a more modern look by using green 7 segments displays.

 

I bought this from hispapanels https://hispapanels.com/tienda/es/leds-displays-lcd/61-soporte-5-displays.html

 

and i'm trying to run it with a 7219, with not so much success. Tried connecting everything acording to the 7219 datasheet and load some scketchs ment to work with this setup, but it's not working at all...

 

Any idea how can i use it? Any better ideas on how to run the displays?

 

Thanks!

[lesthegrngo]

Just been through this with my A10 cockpit. I used an 8 digit seven segment LED display running off a Max7219 board, and this is the sketch that I used for the UHF radio repeated on the dash. It's essentially a rewrite of Craig's sketch for just one module, try swapping in the DSC Bios part you need for the particular unit

 

/*
Tell DCS-BIOS to use a serial connection and use interrupt-driven
communication. The main program will be interrupted to prioritize
processing incoming data.

This should work on any Arduino that has an ATMega328 controller
(Uno, Pro Mini, many others).
*/

#define DCSBIOS_IRQ_SERIAL
#include <LedControl.h>
#include <DcsBios.h>


// 8 DIGIT 7 SEGMENT DISPLAY - UHF RADIO
//pin 3 is connected to the DataIn 
//pin 5 is connected to the CLK 
//pin 4 is connected to LOAD / CS

LedControl lc=LedControl(3,5,4,1); //This creates an instance of a single controller named "lc"

// GENERAL REF NOTE BELOW
/*
The sequence of pins used above are in the following order... LedControl(DIN,CLK,LOAD,# OF IC's) 
pin X is connected to the DataIn 
pin X is connected to the CLK 
pin X is connected to LOAD
the last number...(1) is for how many MAX7219 we have daisy chained. (8 STATED, HOWEVER 4 ACTUALLY PRESENT)
*/

void onUhfFrequencyChange(char* newValue) {
lc.setChar(0,7,newValue[0],false);
lc.setChar(0,6,newValue[1],false);
lc.setChar(0,5,newValue[2],false);
lc.setChar(0,4,newValue[3],false);
lc.setChar(0,3,newValue[4],false);
lc.setChar(0,2,newValue[5],false);
lc.setChar(0,1,newValue[6],false);
 
}
DcsBios::StringBuffer<7> uhfFrequencyBuffer(0x1180, onUhfFrequencyChange);


void setup() {
DcsBios::setup();

// MAX7219 INITIALISATION
//This initializes the MAX7219 and gets it ready for use:

//FIRST - 8 DIGIT 7 SEGMENT DISPLAY - VHF-AM RADIO (CODE) MAX7219 INITIALISATION
lc.shutdown(0,false); //turn on the display
lc.setIntensity(0,8);//set the brightness 
lc.clearDisplay(0); //clear the display 

//FIRST - 8 DIGIT 7 SEGMENT DISPLAY - VHF-AM RADIO (CODE) MAX7219 BOOT CODE WHILST AWAITING SOCAT DATA STREAM
// 
lc.setChar(0,7,'A',false);
lc.setChar(0,6,'1',false);
lc.setChar(0,4,'0',false);
lc.setChar(0,3,'c',false);





}

void loop() {
DcsBios::loop();
} 

 

Hope this helps, I know other have helped me so want to pass on their help

 

Cheers

 

Les

[patogn20]

Just been through this with my A10 cockpit. I used an 8 digit seven segment LED display running off a Max7219 board, and this is the sketch that I used for the UHF radio repeated on the dash. It's essentially a rewrite of Craig's sketch for just one module, try swapping in the DSC Bios part you need for the particular unit

 

/*
Tell DCS-BIOS to use a serial connection and use interrupt-driven
communication. The main program will be interrupted to prioritize
processing incoming data.

This should work on any Arduino that has an ATMega328 controller
(Uno, Pro Mini, many others).
*/

#define DCSBIOS_IRQ_SERIAL
#include <LedControl.h>
#include <DcsBios.h>


// 8 DIGIT 7 SEGMENT DISPLAY - UHF RADIO
//pin 3 is connected to the DataIn 
//pin 5 is connected to the CLK 
//pin 4 is connected to LOAD / CS

LedControl lc=LedControl(3,5,4,1); //This creates an instance of a single controller named "lc"

// GENERAL REF NOTE BELOW
/*
The sequence of pins used above are in the following order... LedControl(DIN,CLK,LOAD,# OF IC's) 
pin X is connected to the DataIn 
pin X is connected to the CLK 
pin X is connected to LOAD
the last number...(1) is for how many MAX7219 we have daisy chained. (8 STATED, HOWEVER 4 ACTUALLY PRESENT)
*/

void onUhfFrequencyChange(char* newValue) {
lc.setChar(0,7,newValue[0],false);
lc.setChar(0,6,newValue[1],false);
lc.setChar(0,5,newValue[2],false);
lc.setChar(0,4,newValue[3],false);
lc.setChar(0,3,newValue[4],false);
lc.setChar(0,2,newValue[5],false);
lc.setChar(0,1,newValue[6],false);
 
}
DcsBios::StringBuffer<7> uhfFrequencyBuffer(0x1180, onUhfFrequencyChange);


void setup() {
DcsBios::setup();

// MAX7219 INITIALISATION
//This initializes the MAX7219 and gets it ready for use:

//FIRST - 8 DIGIT 7 SEGMENT DISPLAY - VHF-AM RADIO (CODE) MAX7219 INITIALISATION
lc.shutdown(0,false); //turn on the display
lc.setIntensity(0,8);//set the brightness 
lc.clearDisplay(0); //clear the display 

//FIRST - 8 DIGIT 7 SEGMENT DISPLAY - VHF-AM RADIO (CODE) MAX7219 BOOT CODE WHILST AWAITING SOCAT DATA STREAM
// 
lc.setChar(0,7,'A',false);
lc.setChar(0,6,'1',false);
lc.setChar(0,4,'0',false);
lc.setChar(0,3,'c',false);





}

void loop() {
DcsBios::loop();
} 

 

Hope this helps, I know other have helped me so want to pass on their help

 

Cheers

 

Les

 

Awesome! Thanks for the help.

 

Question: are you using a display module like this one?

 

https://www.ebay.com/itm/MAX7219-8-Bit-7-Segment-Digital-Tube-Blue-Display-Control-Module-for-Arduino/192851608735?hash=item2ce6da049f:g:0BgAAOSwa2tcg20a

 

Or did you make one from scratch?

 

Thanks!

[lesthegrngo]

I used one of those type. Make sure you don't get the polarity (VCC / GND) the wrong way round, I bricked one by doing that by accident. After that every segment was on and stayed on

 

Cheers

 

Les

Edited January 18, 2020 by lesthegrngo

[BULLITT83]

@lesthegrngo

 

I'm trying also to send COM FQ at a MAX7219, i've a question : do you use your arduino for the 5 volts to "feed" the MAX7219

 

I've problems, testing my sketch with only th eMAX7219 works perfectly, when i have it working with others items ( flaps indicator, gear position leds...) my MAX7219 doesn't works correctly , looks like it has not enough current.

 

 

Regards

 

guillaume

[lesthegrngo]

Yes, the 5v feed from my arduino Nano is the power source for the LED's. On my A10C central warning panel which runs off a Max 7219 driven by a nano, I have 144 green 0805 SMD LED's and the setup is capable of lighting them all. I think it multiplexes the LED's so they are not all lit at the same time, but flash so rapidly it looks like it

 

On my undercarriage indicator lights I drive three 'pirahna' type LED's direct from the nano (obviously no Max7219 for that) so the arduinos are capable.

 

However you could always try and use a MOSFET module (look up Arduino Mosfet module on fleabay) as that allows you to power the LED's and other devices with a separate power supply with the Arduino using the Mossfet as a switch

 

 

Hope this helps!

 

Les

As far as I am aware

[Vinc_Vega]

You are fully right Les. The MAX7219 uses multiplexing.

Btw. MOSFETs are also capable to switch so fast that they can be used with PWM pins to dim LEDs. I did this for my 12V panel backlighting.

[BULLITT83]

Thanks a lot for your answer LES , it helps me a lot

now i'm sure my probleme comes from elsewhere

 

i'll search a little more !

 

thanks a lot !

 

Guillaume