I'm looking to display information using the Arduino...go figure!
Anyway, I'd like to use a 7-segment display or an LED display. The display needs to be big enough to be seen from across the room. I found this 6.5" 7-segment display, which is awfully big, but it seems like the best option. The best option means something cheap (this one is about $300 if it comes assembled, $175 if not) and easy to use with Arduino.
Any thoughts on what would be a cheap way to go about doing this? The display above has serial and ASCII capabilities, so it should play nice with Arduino right?
I'm not so good at the hardware side of this, trying to work on that. Thanks!
It all depends on what information you want to display? Letters? Numbers?
How many digits or letters? How often will it change?
Are you trying to scroll a message?
The link you provided goes to a funky meter that costs a LOT of money because it has a number of scientific inputs for working with sensors.
If you don't need that, then you have much cheaper options.
You can purchase very large LED displays very cheap. OR you can purchase (or make) an array of discrete LEDS. Which depends on how you answer the first questions.
The good news is that regardless of which LED display you choose, the controls are the same and cheap:
Keep in mind that there is also a "display shield". While not as large a display, you could easily put multiple copies of it around the room and then use Ir to send around the information to be displayed.
Hmmm, thanks for the reply it has some interesting information. I'm looking to display 4 digits, or 5 at the most, and probably just numbers. Scrolling would be a nice feature, because then it could scroll through the two values to display, but it is by no means necessary.
Where would I be able to find a cheap LED display?
This Maxim controller is nice because it only takes 3 of the arudino pins. On the software side, will I be able to control it with Serial.print, or am I going to be writing values to the output pins? Both are obviously manageable, but a serial print would be ideal.
Is there any chance of getting any of this prefabricated? I can certainly wire it up myself, but at this point I'd prefer not to have to wire an LED matrix or solder the controller together.
Well, I am thinking of two options. You could make your own 7 segment displays out of leds and some frosted plexi-glass. The other option is to get 5 of the pre-lade 7 segment displays, and carefully glue them together side-by-side. Then you could make some sort of container / frame. Some ideas for that would be some sort of fancy poster board, or if you are good at woodworking, you could make a nuce wooden frame.
I need to know where you are, or at least what countries your comfortable doing business with to answer that question!
I'm in Canada (set your profile "location" for next time) and have had little trouble with vendors in Australia, Taiwan, Hong Kong, USA, UK and other EU countries.
The MAX chip can drive up to 8 digits or an 8x8 array of LEDs. So your 4-5 digits won't be a problem. If you want to do a scrolling display or any other fancy visual effect, you will want to build the 8x8 array of LEDS. Because that will give you the hardware setup to do scrolling and other effects from within software on the Arduino. Mind you, even if you "wimp out" and use 7-segment displays you can still do some fancy things.
The Arduino uses a special type of serial to talk to the MAX chip. There is sample code with the Arduino IDE software. Pretty easy to use.
You still need to tell the Arduino WHAT to display. There are many ways to accomplish that. What works best depends on some of the questions I asked you earlier: how often will the display change?
And where does the information to be displayed come from?
Don't panic when you look at these links, there is a LOT of choice out there. We need to work through what YOU need to pick out the best choices for you.
These are common cathode displays:
These are common cathode matrix displays:
I have not gone through them, but I suspect these are only parts, no finished product. Much cheaper, but you would have to do some soldering and assembly. If you want something pre-fabricated do a google search. Of course, there is no guarantee anybody has made a display as large as you want! I think there is a good chance your going to have to make it yourself.
But don't decide today. Give others a chance to read this thread and comment.
I have more design issues for you. How far away will the display be from the information source?
This will affect your choice of driver chip. The MAX chips has to be near the display, but the I2C interface can run a long way. But if you use a cheaper chip, like the 74HC4511 (or any BCD driver) it might work better to keep the chip near the Arduino, and run long wires to the display.
I'll take a look at the equipment and see what seems to be best and then get some more input for you all.
I've got flexibility with the equipment. I can run wires between any step when necessary. The three major components are the arduino, the controller, and the display. All three can be bundled close together or in separate locations.
The display only updates every 5 minutes or so and it will be getting information off of the interwebs. I've already written code to do this and currently have a mechanical display. All that is left is to adapt it to an easy to read display...
heh. I should have looked first. If you want "large" your only 7-segment choices are:
3" tall:
5" tall:
These are both ONE digit. So you would want to connect 4 or 5 of these, as shown in the Arduino link I posted before and in the MAX 7221 datasheet.
Hmmm.. Looking at the datasheets for these two displays I think I see a problem. They have wired multiple LEDs in series, which likely means the MAX 7221 chip won't put out enough voltage to drive them.
The data sheet for the 7221 shows how to use an external drive to boost power - more hardware work for you though.
With the 8x8 matrix would it scroll across 4 digits? It would be better if they were static and could see all 4 digits.
The scrolling option would be useful only for displaying 2 values, say temperature and relative humidity (just examples). So it would display the temperature, pause...then scroll and display the humidity, pause, and repeat.
An external power supply probably isn't too much of a problem either.
The 74HC4511 does look to be appropriate, and it is awfully cheap. I can get one and just throw it into a breadboard and play around. I will look into it and get back sometime next week.
The 74HC4511 does look to be appropriate, and it is awfully cheap. I can get one and just throw it into a breadboard and play around. I will look into it and get back sometime next week.
Mowcius: This is half on and half off subject... Do you know of anybody that sells the 74HC4511 chip? I am in the USA, so that would be my preferred region... I can't find anybody that sells them individually...
