# Tag Info

6

These panels inherently need A LOT of refreshing, due to their design. It's going to kill the Arduino if you want to do a lot of colors, especially if you'd like to chain these panels. I wrote up a fairly generic explanation on how the 16x32 display works, and you can extrapolate that to the 32x32 panel, which basically just adds another address line. ...

4

Apart from the reed relay driver, you need a 2 position switch on each dot terminal that toggles between Ground and +24V, and another switch on the common terminal (5,9,10) that also connects to +24V or Ground. The circuit should look something like this:- When S1 is switched to Ground and K1 is closed, any dot which is switched to +24V will be flipped to ...

3

Whether you use a microcontroller, FPGA or wired logic the principle is the same. You scan through the LEDs (typically with a 5x7 characters say 20 across you might have 100 sink drivers, one for each column and 5 source row drivers. You scan the display by turning on the desired sink drivers for each row and turn on the appropriate row driver. The cycle ...

3

What reasons might have made this mapping of memory to display a good idea? This layout makes it extremely easy to display 8 lines of text on the display -- an 8-pixel-high character font can be stored as a sequence of 8-bit values to be written to the display. This display mode has the advantage of making it easy to draw text at any horizontal position, ...

3

For running two of the matrices with identical display information, the control lines (address and data) can be hooked up to both panels in parallel, identical pin for pin, since the inputs to the panel are high impedance i.e. they will draw very little current from the Arduino. GPIO pin count on the Arduino will also thus remain the same. Thus, simply ...

3

I just simulated the character you added to your question, and it looks OK to me. For reference, I wrote this code: unsigned char cha[] = {0x00, 0x0C, 0x00, 0x03, 0xC0, 0x01, 0x30, 0x01, 0x0C, 0x01, 0x30, 0x01, 0xC0, 0x01, 0x00, 0x03, 0x00, 0x0C, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}; void main(void) { int i; int j; for (i=0; i<...

2

You don't say which display you are working with and you don't show any font data in your question, so I can't say for sure, but usually these types of LCD's, if they are black-and-white, are written to one byte at the time. The byte will set the values of one vertical column of 1x8 pixels. For a 13 wide, 16 pixels high font, you'd need to first write the ...

2

You are using i2c to communicate with the GPIO expander. I2C is relatively slow with the result that there will be hundreds of microseconds between the commands to write to device 0x12 and 0x13. During that time the output of the GPIO expander output at 0x12 will be set to the new data but 0x13 will still be from the the previous data - this can result in ...

2

Page 3 of the MAX7129 datasheet specifies a minimum logic-high input voltage $\mathrm{V_{IH}}$ of 3.5V. So if your ESP32 is a 3.3V device then it cannot provide a high enough voltage to reliably operate the MAX7129. So yes, voltage levels / logic levels are probably the culprit here.

2

It is probably this rebranded Winstar display. The controller is WS0010. It is HD44780 compatible, but additionally has graphics mode.

2

I wasn't able to find a 12+ driver with a quick google search, but a fairly easy(although larger) implementation would be to just use two LM3914's. There's an example in this spark fun tutorial Just hook up LEDs 1-10 to the first one, then feed the RLO output to the RHE of the next driver and connect the last 2 LEDs to it. Edit: Information added as ...

1

With that expander, it requires 2 I2C bus transactions to change both of the A and B banks. Assuming the I2C is running at 100kHz, each write is going to take at least 26 mS (8 bit address, 8 bits data, 2 ACK bits, start and stop). Add code overhead from running Python, I’m going to guess you’re closer to 50 mS per write. It looks like you have a 1000 mS ...

1

There is any number of led or segment driver that can handle this. Just cause each LED has it's own anode pin does not mean you have to use it like that. Simply tie the anodes together and drive them like that. Suddenly you have gone from 64 individual lines to drive, to 16. In the same exact 8x8 matrix configuration. Of course now you have to deal with ...

1

I doubt there is an IC out there just for controlling 64 lines in a grid pattern. Now, since you mentioned things like the Mux Shield, Arduino, and Pi in your question and comments, would 8 shift registers be sufficient? I know that this would work because I actually built a non-multiplexed LED array using 8 74HC595 shift registers and 64 individual wires ...

1

This type of display memory layout is actually more common on small display controllers than you might think. In all the different LCD / OLED graphics display controllers that I have programmed to over the years this layout is the most common. Horizontal byte layouts exist for sure but are less common. The display controller designer works out the ...

1

I think that you should consider a detailed functional study of the product at the operator level first. Then you can understand the operational behaviors of the components of the system. As far as buttons and selectors: These are so easy to understand in terms of function that there is little to "reverse engineer" with them. Simple momentary push switches ...

1

Futaba doesn't grant open access to product information for some arcane reason, so you have to register on their site just to search for what is available. You probably have to submit an inquiry to get the datasheet proper, and I'd bet that you have to do so as a business to get a reply. Not very good marketing if you ask me, but they don't care. ...

1

It's usually impossible to answer something asking for "best" or "optimal", but it's safe to say that 35 relays is not optimal. You have omitted crucial data - holding current for the coil. If I'm not completely mistaken here, it seems to me that you can simply connect NPN transistors to the coil, one per dot, and drive them directly from shift registers. ...

1

As per datasheet the IC can regulate the current through the LEDs by using a single resistor on the Iset pin. So you don't need resistors for each of the LEDs but you do have to take care to select one.

1

Daniel suggested This page which looks very similar to yours but not mechanically identical, and there are others like it on the net (as you note). The rear view shows rows of many probably identical ICS and a few others near the input connectors. If you had one of these 'in your hand' trhe IC types would tell you quite a lot. However, Daniels page has the ...

1

You will need to know the pinout of the display. The physical wiring of any device may be completely different from the logical wiring of the device. This is for reasons of manufacturing simplicicty, amongst others. That's why we call them "schematics". As the commenters have said, look up the data sheet of the device, and that will reveal the pinout. Be ...

1

Why do you need to use a ROM or EPROM/EEPROM? How are you planning on using that to drive these LEDs? What you're trying to do is easy to accomplish with any microcontroller. You'll need to multiplex the LEDs (so you don't have to drive each individually) and connect at least one side of the LEDs (rows or columns) to a driver like the ULN2803. There is tons ...

Only top voted, non community-wiki answers of a minimum length are eligible