New Big LED sign powered by Raspberry Pi

I have made another big LED sign, but this time it is powered by a Raspberry Pi.  At first I used the Adafruit Hat ,but I have upgraded to the three HUB75 Hat from ElectroDragon! This enalbes three chains of LED arrays. So far I have 5 32x32 panels in each chain but I will likely expand that.

This is a view of the back of the assembled panel. I am using metal brackets to hold the panels together as they have on inch spacing. 24mm is ideal as the one inch spacing leaves about a two mm space between the panels. I have a 3D printed version of the brackets on thingiverse and have used them in other designs.

Here is a couple of pictures of the panel being lit up. The text demo is limited to one line of panels.

There are several demo programs to check out the proper operation of the Raspbery Pi adapter.

Here is a link to the video of the demos;

https://youtu.be/44ykJb_ZB7A?si=ylKY5zBix4FU4i2X

Testing LED panels for bad LED's

I have written two programs to test LED panels after someone sold me a pile of them with many bad LED's.  Some panels had over 30 LED's that were not working.  He also shipped them with no padding between the LED's!  This resulted in smashed LED's and some of the alignment nubs were broken off.  Fortunatly with some soldering I was able to reduce the number of bad LED's to 3 or 4 per panel.  Some LED's had broken runs but most of them just needed to be resoldered.

The first program tests the colors and leaves the panel white for quickly testing if the LED's just soldered are working.  This does not work on 16S panels for some reason.

// RGBcolors test for Adafruit RGBmatrixPanel library.

// For testeing LED arrays for bad bits.

#include <RGBmatrixPanel.h>

#define CLK  8   // USE THIS ON ARDUINO UNO, ADAFRUIT METRO M0, etc.

#define OE   9

#define LAT 10

#define A   A0

#define B   A1

#define C   A2

#define D   A3

// Does not work with 16S panels if you add "D" nothing happens!

RGBmatrixPanel matrix(A, B, C, CLK, LAT, OE, false);

void setup() {

  matrix.begin();

   // fill the screen with colors

  matrix.fillRect(0, 0, 32, 32, matrix.Color333(0, 7, 0));

  delay(1000);

  matrix.fillRect(0, 0, 32, 32, matrix.Color333(7, 0, 0));

  delay(1000);

  matrix.fillRect(0, 0, 32, 32, matrix.Color333(0, 0, 7));

  delay(1000);

  matrix.fillRect(0, 0, 32, 32, matrix.Color333(7, 7, 7));

  delay(1000);

}

void loop() {

}

The next program is for sorting LED panels by how they are internally wired.  There are 16S, 8S (There are many varieties of 8S) and 4S panels.  It scans all LED's one at a time.

I could not get this to work with the normal drivers so I wrote my own using "bit banging".  Its slow but works great!

// RGB bitbang test bits by scanning

#define CLK  8  

#define OE   9

#define LAT 10

#define A   A0

#define B   A1

#define C   A2

#define D   A3

#define R1  2

#define G1  3

#define BL1  4

#define R2  5

#define G2  6

#define B2  7

int tbit;

int row;

int col;

void setup() {

  pinMode(A, OUTPUT);

  pinMode(B, OUTPUT);

  pinMode(C, OUTPUT);

  pinMode(D, OUTPUT);

  pinMode(CLK, OUTPUT);

  pinMode(OE, OUTPUT);

  pinMode(LAT, OUTPUT);

  pinMode(R1, OUTPUT);

  pinMode(G1, OUTPUT);

  pinMode(BL1, OUTPUT);

  pinMode(R2, OUTPUT);

  pinMode(G2, OUTPUT);

  pinMode(B2, OUTPUT);

  }

void loop() {

  // Set sequential bits

  for (col=0; col<16; col++){

    for (row=0; row<32; row++){

      for (tbit=0; tbit<32; tbit++){

        digitalWrite(R1, LOW);  

        digitalWrite(G1, LOW);  

        digitalWrite(BL1, LOW);  

        if (tbit == row){

          digitalWrite(R1, HIGH); 

          digitalWrite(G1, HIGH); 

          digitalWrite(BL1, HIGH); 

        }

      digitalWrite(CLK, LOW);  //Clock data in

      digitalWrite(CLK, HIGH);  

      } 

    // latch and display results

    digitalWrite(OE, HIGH);  // disable output while latching data.

    digitalWrite(LAT, LOW);  

    // select next column if it has changed

    digitalWrite(A, LOW);

    digitalWrite(B, LOW);

    digitalWrite(C, LOW);

    digitalWrite(D, LOW);

    // update row selection

    if ((col & 0x0001)>0)digitalWrite(A, HIGH);  

    if ((col & 0x0002)>0)digitalWrite(B, HIGH);  

    if ((col & 0x0004)>0)digitalWrite(C, HIGH);  

    if ((col & 0x0008)>0)digitalWrite(D, HIGH);  

    digitalWrite(LAT, HIGH);  

    digitalWrite(OE, LOW);  

    delay(20);

    }

  }

}

Explaining the different types of LED Arrays

Not all LED arrays are the same, there are many varieties within a set size and set amount of LED's.  There are the P numbers.  P10 means 10mm LED spacing.  P6 is 6mm spacing.  P3 is 3mm spacing.

Then there are the S or scan or row select numbers.  Typical S numbers are S4, S8, and S16.  But they even vary within these numbers!  Lets start with a 16S arrangement.  In a 32 by 32 LED array there are two 32 bit shift registers one for the top half and one for the bottom (As well as one for each color).  Then there are 16 row selectors that select what two rows are currently lit up.

Next there is an 8S LED array.  Withing a 32x32 array there are four 32 bit shift registers.  The top two and the bottom two are sequential. (This is for each of the three colors) Then there are 8 row selectons.  These select what four rows are currently lit up.

Now things get tricky.  Some arrays do not follow the normal pattern.  For instance the modified 8S panel depicted below.  These are not compatable with some controllers.  There are two 16 bit shift registers and a 32 bit shift register for the top half and the same for the bottom.  (This is for each of the three colors)  The shift register sequence is the top 16, then the middle 32, then the other top 16 bits.

So not only are you dealing with color differences between different batches you are dealing with scanning differences.  You cannot mix an 8S and a modified 8S in the same chain of LED arrays.

Big LED sign with 6x4 of 32x32 P6 LED panels

My latest LED sign is by far my biggest LED sign yet!  I purchased a pile of P6 32x32 LED panels on eBay for about $10 each.  The seller even included the cables needed to get it to work!

Here is a picture of it with a TF-QS3N Controller.  It uses PowerLED to set it up from a computer over a newwork.

This is the back side of the sign as I was assembling it.  The sign is now over twice the size shown in this picture.

Here is a newer picture at 4 by 7 panels.  It is now 5 by 7 panels in size and growing!  I hope to get to 5 by 8 panels but the model numbers of the next panels do not match and the color balance might be too far off to intermix them.

One option to connect the panels together is these metal brackets available at most hardware stores at four for $5.00.  Thes have a hole spacing of one inch (24.5mm) and the panel mounting holes are 24 mm so there is a 1.5 mm gap between the panels if you uses these brackets. 

I have 3D printed my own brackets for connecting the panels.  They were designed on TinkerCad.  The STL files are available on thingiverse. 

Here is a video of when I first got them working.

Expanding my sign with 16x16 addressable LED arrays.

 I am expanding my sign with 16x16 WS2812B Addressable LED arrays.  Currently I am at 3x5 of these arrays but am working on adding three more for a 3x6 or 48 by 96 sign.

This is the built in demo with a T8000 controller.  I had more luck with the SP801E controller.

Here I am starting to add the grids to make the pixels square.  The grids are on thingiverse.  I drilled too many holes in the luan because I confused the orientation.  They need to connet from top to bottom.

This is another picture of assembling the arrays.  I am using E-6000 glue to hold them in place.  I glue two or three at a time just in the corners then put something on them to hold them in place till the glue dries.

Here is the first video with the T8000 controller

https://www.youtube.com/watch?v=STn5s0Ipr-M

This is a demo with an SP801E controller

https://www.youtube.com/shorts/VzCqLekaI-U

Here it is with WLED on an ESP32 processor

https://youtu.be/ZxGXOkgYxrg

Here are some pictures from the WLED demo.

Sunrise Systems LED Sign revisited

 I was asked to convert another Sunrise Systems LED sign to Arduino control and wireless updates via bluetooth.  This time I wanted to make the conversion simpler by reusing the driver IC's and Transistors.  To do that I cut the board in half just to the right of the processor.  Then I tapped into signals on the 74HC04 and 74HC138.  The following picture shows the location for the cut and where to tap into the signals:

Here is a picture of the prototypeing of this new setup.  Everything worked but some of the signals were inverted so it took some playing with the code to get it to work.

I spliced in a bare board to add the arduino processor. 

Here is the revised code for a basic version of this arrangement;

// Sunrise 7x96 Uno LED Array driver

// Easier to read code

// 4/4/2024 by Bob Davis

#define Data 7// Data pin

#define CLK 8 // Port B assignments 

#define OE  9 // 74138 pins 4 and 5

#define LAT 10// Latch

#define A0 11 // 74138 pin1

#define A1 12 // 74138 pin2

#define A2 13 // 74138 pin3

String text="ARDUINO+SUNRISE  ";

// This font from http://sunge.awardspace.com/glcd-sd/node4.html

byte font[][7] = {

0x00,0x00,0x00,0x00,0x00,0x00,0x00, // ascii 32

0x00,0x00,0xfa,0x00,0x00,0x00,0x00, // !

0x00,0xe0,0x00,0xe0,0x00,0x00,0x00, // "

0x28,0xfe,0x28,0xfe,0x28,0x00,0x00, // #

0x00,0x34,0xfe,0x58,0x00,0x00,0x00, // $

0xc4,0xc8,0x10,0x26,0x46,0x00,0x00, // %

0x6c,0x92,0xaa,0x44,0x0a,0x00,0x00, // &

0x00,0xa0,0xc0,0x00,0x00,0x00,0x00, // '

0x00,0x38,0x44,0x82,0x00,0x00,0x00, // (

0x00,0x82,0x44,0x38,0x00,0x00,0x00, // )

0x10,0x54,0x38,0x54,0x10,0x00,0x00, // *

0x10,0x10,0x7c,0x10,0x10,0x00,0x00, // +

0x00,0x0a,0x0c,0x00,0x00,0x00,0x00, // ,

0x10,0x10,0x10,0x10,0x10,0x00,0x00, // -

0x00,0x06,0x06,0x00,0x00,0x00,0x00, // .

0x04,0x08,0x10,0x20,0x40,0x00,0x00, // /

0x7c,0x8a,0x92,0xa2,0x7c,0x00,0x00, // 0

0x00,0x42,0xfe,0x02,0x00,0x00,0x00, // 1

0x42,0x86,0x8a,0x92,0x62,0x00,0x00, // 2

0x84,0x82,0xa2,0xd2,0x8c,0x00,0x00, // 3

0x18,0x28,0x48,0xfe,0x08,0x00,0x00, // 4

0xe4,0xa2,0xa2,0xa2,0x9c,0x00,0x00, // 5

0x3c,0x52,0x92,0x92,0x0c,0x00,0x00, // 6

0x80,0x8e,0x90,0xa0,0xc0,0x00,0x00, // 7

0x6c,0x92,0x92,0x92,0x6c,0x00,0x00, // 8

0x60,0x92,0x92,0x94,0x78,0x00,0x00, // 9

0x00,0x6c,0x6c,0x00,0x00,0x00,0x00, // :

0x00,0x6a,0x6c,0x00,0x00,0x00,0x00, // ;

0x00,0x10,0x28,0x44,0x82,0x00,0x00, // <

0x28,0x28,0x28,0x28,0x28,0x00,0x00, // =

0x82,0x44,0x28,0x10,0x00,0x00,0x00, // >

0x40,0x80,0x8a,0x90,0x60,0x00,0x00, // ?

0x4c,0x92,0x9e,0x82,0x7c,0x00,0x00, // @

0x7e,0x90,0x90,0x90,0x7e,0x00,0x00, // A

0xfe,0x92,0x92,0x92,0x6c,0x00,0x00, // B

0x7c,0x82,0x82,0x82,0x44,0x00,0x00, // C

0xfe,0x82,0x82,0x82,0x7c,0x00,0x00, // D

0xfe,0x92,0x92,0x92,0x82,0x00,0x00, // E

0xfe,0x90,0x90,0x80,0x80,0x00,0x00, // F

0x7c,0x82,0x82,0x8a,0x4c,0x00,0x00, // G

0xfe,0x10,0x10,0x10,0xfe,0x00,0x00, // H

0x00,0x82,0xfe,0x82,0x00,0x00,0x00, // I

0x04,0x02,0x82,0xfc,0x80,0x00,0x00, // J

0xfe,0x10,0x28,0x44,0x82,0x00,0x00, // K

0xfe,0x02,0x02,0x02,0x02,0x00,0x00, // L

0xfe,0x40,0x20,0x40,0xfe,0x00,0x00, // M

0xfe,0x20,0x10,0x08,0xfe,0x00,0x00, // N

0x7c,0x82,0x82,0x82,0x7c,0x00,0x00, // O

0xfe,0x90,0x90,0x90,0x60,0x00,0x00, // P

0x7c,0x82,0x8a,0x84,0x7a,0x00,0x00, // Q

0xfe,0x90,0x98,0x94,0x62,0x00,0x00, // R

0x62,0x92,0x92,0x92,0x8c,0x00,0x00, // S

0x80,0x80,0xfe,0x80,0x80,0x00,0x00, // T

0xfc,0x02,0x02,0x02,0xfc,0x00,0x00, // U

0xf8,0x04,0x02,0x04,0xf8,0x00,0x00, // V

0xfe,0x04,0x18,0x04,0xfe,0x00,0x00, // W

0xc6,0x28,0x10,0x28,0xc6,0x00,0x00, // X

0xc0,0x20,0x1e,0x20,0xc0,0x00,0x00, // Y

0x86,0x8a,0x92,0xa2,0xc2,0x00,0x00, // Z

};

void setup() {

  Serial.begin(9600);

  Serial.println("Arduino is ready");

  pinMode (Data, OUTPUT); // Data pin to output

  pinMode (CLK, OUTPUT);  // Clock pin to output

  pinMode (OE, OUTPUT);   // Out Enable pin to output

  pinMode (LAT, OUTPUT);  // Latch pin to output

  pinMode (A0, OUTPUT);   // Address pin to output

  pinMode (A1, OUTPUT);   // Address pin to output

  pinMode (A2, OUTPUT);   // Address pin to output

}

     

void loop() {

    if (Serial.available() > 0){

      text=Serial.readString();

      text.toUpperCase();

      Serial.print(text);

      }

    // Select the Row

    for (int r=0; r<8; r++){

      // select the character

      for (int ch=17; ch>-1; ch--){

        // select the column within character

        for (int c=5; c>-1; c--){

          digitalWrite(Data, HIGH); // Data is inverted!

          if ((font[text[ch]-32][c] >> r+1) & 0x01==1) digitalWrite(Data, LOW);

          digitalWrite(CLK, LOW);  // Toggle Clock

          digitalWrite(CLK, HIGH);

        }

      }

      // This row is done so display it

      digitalWrite(OE, HIGH);  // Turn off display

      digitalWrite(LAT, HIGH); // Latch  data

      digitalWrite(LAT, LOW); // Ready for next latch

      digitalWrite(A0, LOW);  // Update Row 

      digitalWrite(A1, LOW);

      digitalWrite(A2, LOW);

      if ((r & 0X01)==1) digitalWrite(A0, HIGH);

      if ((r & 0X02)==2) digitalWrite(A1, HIGH);

      if (r > 3) digitalWrite(A2, HIGH);

      digitalWrite(OE, LOW);  // Display back on

      }

    }

Here is a picture of the wiring from the back side.

InMoov Compatible Hand Design Upgrade

I am working on a InMoov Compatible Hand Design Upgrade.  The main goal is to put all the servos in the hand.  Years ago I printed out a hand only to discover that all the servos are in the forearm.  Recently I though I could do better.  So far I am on my third hand.

This is what it looks like so far.  I used the one piece finger segments and printed them laying down with supports to plate only.  The servo arms will need to be two sided or 3D printed.

Onthe left are the first three attempts to print the improved hand.  In the latest version the servos are indented 6mm so they stick out the back side of the hand slightly.

Converting TV to LED sign with 16x16 Arrays and SP801E

 I have been Converting an  old TV into a LED sign with 16x16 Arrays and SP801E controller.  At first I had 8 of the 16x15 ws2812 LED arrays then I added two of the 8x32 LED arrays to better fill in the screen area.

Here are two demo pictures.  One is a built in pattern and the other is a picture of my wifes pineapple upside down cake.

This is a close up picture of the controller.  I am only using 3 of the 4 outputs of the SP801E.  Each output can light up to 1024 LED's.

The screen is still not completely covered with the LED arrays.  But I do not know how to fill inthe last couple of inches of screen area.

Here is the latest video of the LED sign.

https://youtu.be/5pAZimfBC9Q?si=xXcdMZ7I8MxYsIe8

Repair of Suzuki GP-3 Digital Piano

My brother dropped off a Suzuki GP-3 electric digital piano for repairs. Many of the keys were stuck in the down position.  So I googled how to fix it and here is what I found:

Here is a video telling how to take it apart:

https://www.youtube.com/watch?v=KE7A7I0mirg

Then I found this coment on how to fix it at: 

https://www.yamaha-keyboard-guide.com/suzuki-keyboard-repair.html

"I used the orange fibreglass driveway marker from Home Depot. It’s the perfect size. With a rubber mallet I used it to punch out the old rods and replace them at the same time."

The first step was to remove the keys from the piano.

Then I tried to remove some of the individual keys. BTW you do not need to number the keys they are already numbered in the indentation area.  

Eventually I decided to remove every other octave, then remove all of the rods, then carefully push an orange driveway marker through all of the octaves.  I left the angled tip on the rod, and still had to lift some keys slightly to get the rod to go through them.  The commentator above said that he drove the marker through pushing the rods out as he went, but my keyboard was so far gone that that was not a possibility.  I had to use some pliers to twist and pull out the rods, one at a time, as they were really stuck in place.

When I put it back together there were way too many screws left over.  So I took it back apart and put in a lot of missing screws.  Even so I still had about 16 screws left over!!  

Rocker Bogey 6 Wheel Drive Mars Rover

 I had about eight wheels and matching motors around so I decided to make a six wheel drive Arduino controlled rover.  Then I discovered the rocker-bogie design that can handle really fough terrain.  So I 3D printed a design and modified it for a bigger platform for the electronics.

I have not figured out the front suspension yet and I would love to include one of my 3D prited Nerf guns in the design!

I cut a hold to mount a rotating servo in the middel of the platform.  there is not enough room for the arduino, batteries, and motor controller!

Peavey Combo 115 repairs

My brother bought me a Peaver Combo 115 for repair.  They used controls with plastic shafts that broke off. They upgraded the design to use controls with metal shafts but they are out of stock everywhere unless you want to pay a fortune for them.

Here is a picture of the controls with their values and part numbers next to them.  You can see the broken controls in the picture.

This shows what the insides of the amplifier looks like. All of this could be 1/4 the size if it was made today.

The only critical controls that were broken were the 50K linear tone controls. The crossover and compressor can be ignored or bypassed.

Here is a possible source of parts.  The needed parts will cost you over $50 with shipping and may not be in stock.

As a solution I purchased 10 x 50K pots with knobs on eBay.  Short wires have to be run from each control to the circuit board.  I have seen this kind of solution before.

 

WARNING - 5630 LED strip lights are burning out!

I have many 5630 LED strip lights that have burned out after only 2 months of use.  Here is what they look like now that they have been replaced:

I used these LED strips to replace the five foot flouresent light bulbs in a street sign.  Here are the bad LED's as they were starting to burn up.  By the time I replaced them many more had burned out.

Arduino Powered Colloidal Silver Maker with Nokia 5110

I saw that someone had copied my colloidal silver maker design and their design was trending at number one when you search for Arduino Colloidal Silver Maker.  So I thought I would improve my previous design to use a Nokia 5110 LCD in the design instead of the 1602 LCD.  This Nokia display gives five or six lines of display so you can see more information.

I use a computer power AC adapter to power the colloidal silver maker at about 19 VDC. Most people say that 18 to 20 volts is ideal for this application. 

This is a picture of the Nokia display.  I added the ability to see the current setting as it reduces every time the current exceeds 1ma.  What else do you think I should display on the LCD?

Adding the Nokia display is easy as it just plugs into the Arduino Uno except for jumpers to 3.3 volts and ground.  Voltage dropping resistors are not needed as the Nokia chip is 5 volt tolerant.  You can jumper the BL (backlight) to 3.3 volts or add a jumper or resistor right on the LCD.

The top view has not changed from the previous version.  There is a voltage divider so the arduino analog inputs would not be damaged and a L293 motor driver IC module.  The motor driver has its own internal 5 volt regulator.  Use a separate ground for the voltage divider to avoid motor noise.

Here is the code:

#include <Adafruit_GFX.h>

#include <Adafruit_PCD8544.h>

// Software SPI (slower updates, more flexible pin options):

// pin 7 - Serial clock out (SCLK)

// pin 6 - Serial data out (DIN)

// pin 5 - Data/Command select (D/C)

// pin 4 - LCD chip select (CS)

// pin 3 - LCD reset (RST)

Adafruit_PCD8544 display = Adafruit_PCD8544(7, 6, 5, 4, 3);

// Pins for Colloidal silver maker

int CS1=10;

int CS2=11;

// Pins for stirrer

int Stir=9;  // Moved to pin 9!

int Shutdown=0;

// Variables for time

int hours;

int minutes;

int seconds;

long hour = 3600000; // 3600000 milliseconds in an hour

long minute = 60000; // 60000 milliseconds in a minute

long second = 1000; // 1000 milliseconds in a second

float AN1=0.0; // Analog inut 1

float AN2=0.0;

float temp1=0.0;

float temp2=0.0;

float CUR=0.0;  // Current in ma

int CurSet=255; // Current Setting

void setup()   {

  display.begin();

  display.setContrast(60);  // Default is 50

  display.clearDisplay();   // clears the screen and buffer

  pinMode (CS1, OUTPUT);

  pinMode (CS2, OUTPUT);

  pinMode (Stir, OUTPUT);

}

void loop() {

  display.setTextSize(1);

  display.setTextColor(BLACK);

  // Reverse current every 30 minutes

  if (Shutdown==0){

    analogWrite(Stir, 128); // 1/2 supply voltage

    if (minutes<30){

      analogWrite(CS1, 0);

      analogWrite(CS2, CurSet);    }

    else{

      analogWrite(CS2, 0);

      analogWrite(CS1, CurSet);    }

  }

  else{

    analogWrite(CS1, 0);

    analogWrite(CS2, 0); 

    analogWrite(Stir, 0);     }

  temp1=analogRead(A1);

  AN1=((temp1*5.0)/1024.0)*4.0;

  temp2=analogRead(A2);

  AN2=((temp2*5.0)/1024.0)*4.0;

  CUR=abs(AN1-AN2);

  if (CUR > 1.0) {CurSet--;} // Reduce PWM

  display.clearDisplay();

  display.setCursor(0,0);

  display.print("V1:");

  display.print(AN1);  // Analog 1

  display.setCursor(0,10);

  display.print("V2:");

  display.print(AN2);  // Analog 2

  display.setCursor(0,20);

  display.print("Cur:");

  display.print(CUR);  // Current

  display.setCursor(0,30);

  display.print("CurSet:");

  display.print(CurSet);  // Current Setting

  // print the number of seconds since reset:

  long timeNow = millis();

  hours = (timeNow) / hour;             

  minutes = ((timeNow) % hour) / minute ;

  seconds = (((timeNow) % hour) % minute) / second;

  display.setCursor(0, 40);

  display.print("Time:");

  display.print(hours);

  display.print(":");

  display.print(minutes);

  display.print(":");

  display.print(seconds);

  display.display();

  if (hours>3){ // Time under 4 hours

    Shutdown=1;

    }

  if (CUR>2.0){ // Current under 2ma

    Shutdown=1;

    }

  delay(500);

}

There was an error in the connections to the L293 motor driver in my earlier version.  The VIN of 19-20 volts goes to pin 8.  Also the stirrer has been moved to D9 as the Nokia LCD needs D3.