LED Matrix Kit

Hi, ALL I buought 8x8 LED Matrix kit and found an article about how to do it. http://linksprite.com/wiki/index.php5?title=LED_Matrix_Kit I installed all into LED matrix module, pluged with arudino uno, copied the code and upload. Nothing happened.

I found there are Jumper Wires in the article. I wonder if I really can't power LED matrix module by connecting Arduino 5v and GND pin?? As the article described, "Use independent power supply for the 8x8 LED Matrix Shield, and the supply voltage is 5V/2A." and "The 8x8 LED Matrix must be common-grounded with the Arduino module;" I don't know what is " common=grounded with Arduino module". I also can't find independent power supply for LED Matrix. As the picture showed, LED Maxtrix seems to be powered by Arduino 5V and GND pins. Is there something I mess up?? Thanks.

slinbody: I wonder if I really can't power LED matrix module by connecting Arduino 5v and GND pin??

Yes, you can.

Hi,

Are you using the exact same kit as shown in the wiki? What model of Arduino are you using and how are you powering it? Have you managed to run the blink sketch ok? Have you made any changes to the sketch from the wiki?

Please post a close-up well focussed picture of your circuit and how you are connecting it to the arduino.

Common grounded means that when you have two power supplies in the same curcuit, you must have a wire connecting the ground (0V) connections of the two power sources.

For a power supply, you could use any mains adaptor that is rated at 5V and 2A, but it must be regulated. Often you cannot tell if a power supply is regulated by reading the label. Use your dmm to check the voltage of the power adaptor when it is plugged in but not connected to anything. If it reads 5V it is probably regulated. An unregulated 5V adaptor will read several volts more than 5 with nothing attached. If you don't have a dmm, get a dmm!

Paul

slinbody - just in case you are not aware a dmm is a digital multimeter - for checking voltage, current and resistance in electrical circuits and like Paul says

PaulRB: If you don't have a dmm, get a dmm!

You can use the power from the Arduino. With both similar kits I got on eBay and my own Parola hardware (link below if you are interested) I have had quite a few (up to 20) units connected to the Arduino power supply and they work fine.

Common grounded means that you need to connect the ground signal of the Arduino, Power Supply and the LED module together.

marco_c: You can use the power from the Arduino. With both similar kits I got on eBay and my own Parola hardware (link below if you are interested) I have had quite a few (up to 20) units connected to the Arduino power supply and they work fine.

A single matrix plus MAX7219 should draw under 200mA, easily powered from the Arduino 5V pin.

20 of them? I'm not sure I believe that.

Thanks for replies. I buy the same one as the article. I tried to install all on the breadboard except the PCB board today. The LED started to light. I think I didn't know how to install all on the PCB perfectly. (I also have changed another PCB. )

Just to be sure, so that we are covering the obvious things.

  1. The kit parts need to be soldered to the PCB that was supplied. You cannot just place the components on the board, like a breadboard.
  2. You need to connect the Arduino pins to the IN side of the PCB connector once it is in place (one of the signals is called DIN or Data IN). The out side has DOUT.

The kit parts need to be soldered to the PCB that was supplied. You cannot just place the components on the board, like a breadboard.

No, REALLY ?

Awesome project Marco !!!
We need to find a school to undertake some kind of Guinness Book of World Records for the longest PAROLA display .

Robert

No, REALLY ?

It is always worth covering the very basics and assuming nothing, especially when people are just learning how to do things. You would be surprised how many time a question like "Is the power on?" is the right question to ask.

I guess you have a point. Have you ever considered the fact that in a way this "silent radio" concept if considered on a one character basis is equivalent to visual morse code, in the sense that if you built a single 8x8 matrix large enough it could be seen from quite a distance away, possibly beyond the range of ordinary cheap walky-talkies (approx 1/2 to 1 mile in normal surroundings) yet is not affected by the constraints of radio transmission, (interference, cross-talk, regulatory pwr limits , etc..) If you take the anode to cathode voltage of every one of the 64 leds in a single 1588BS MATRIX , common anode or common cathode, the voltage to turn any led on is still going to be the correct voltage to turn on a solid state device, whether it's an N-Channel Mosfet , or a solid state relay. That means that if you "super-sized" a single 8x8 matrix and used incandescent, halogen, led or other source of round light sources in an 8x8 matrix , ranging in size from 1 foot square to 8 foot square, and cycled your message one letter at a time it would be faster than morse code and would have the advantage that anyone could read it. Beyond a certain range, morse code works better because it is binary (ON/OFF) and you don't have to be able to read anything . Either you see the light or you don't, whereas the matrix has to be close enough to make out the letter. Where I see this concept fitting in is that because you don't have the constraints of radio (channel interference), it would be convenient for anyone to communicate with anyone anywhere outdoors that is beyond human voice range , like in a hiking , camping , (or desert) scenario. I think the limitation is the power capacity of an automobile alternator & battery with the engine running. If you wanted to make something for use between campsites where there is no cell coverage it would probably sell at camping supply stores because if you provided a keyboard with the whole alphabet then anyone of any nationality or language could use it. I don't know if you've ever been camping but when you apply for your campsite permit , sometimes there is super long waiting list and you can't always get the site you want. I just think it might be a usefull tool If someone had an accident or got sick and there is no cell coverage and you are out of voice range what are you going to do ? I guess most people would opt for the age old SOS with a flashlight but maybe a one-foot square bright led matrix would be better because you could send a message that someone just got bit by a snake and send anti venom or something like that. Just a thought ...

That was a very common practice in the 1700’s to the late 1800’s… then came Marconi…
Power efficiencies and a lack of a detector except the branley coherer (Ref: http://en.wikipedia.org/wiki/Coherer which was sevral orders of efficiency lower than the human eye… But it worked at night and through fog, rain and, Yes… even snow. or over the horizon… made the device somewhat inefficient But Radio was born… and for the most part eliminated semaphores as a viable all weather method of communication…
Now what used to take several thousands of watts of input power housed in a small room can be held in the hand and draw less than 5 watts of power… Oh Yes, the Antenna… An antenna that is at all efficient in the 50 to 200 kilocycle range is a rather large and imposing structure so equipment that operated in the 1 to 10 Million cycles per second range soon replaced the old Spark Gap transmitter and could be mounted in a movable device…, All this nearly 120 years ago… What will science think of next?

DocEdison…
—> WA7EMS <—

That's great. Only there's no cell phone signal where most people go camping and not everyone has walky talkies and usually only the emergency services have a VHF radio so yeah, a VHF radio is the only reliable radio communication in the mountains. There's no question , that's the best way to communicate with emergency services, hands down. The question is , does that leave any application left for the semiphore (alphnumeric) now ? If not , then forget it. The point is that a VHF radio is probably going to cost about $100 . Believe it or not, some people can't afford that. Yet a one-foot 8x8 alphanumeric led matrix that runs off a car battery could probably sell for under $25. Will that help anyone ? Who knows ? It's not breaking news that semiphores are ancient technology. Everyone knows that. The question is "Is there any place for a new-technology version of an ancient device ? If not , then fine. I'm not trying to sell them or anything. It was just thought. If you think that's a waste of time to consider the idea that's fine. It doesn't bother me that you point out that it is old technology. I sort of expected someone to be skeptical. It doesn't hurt to consider ideas that are unusual. It's possible that the market for such a device is not emergency related at all , but rather social networking in the wild . Who knows ?

marco_c: Just to be sure, so that we are covering the obvious things.

  1. The kit parts need to be soldered to the PCB that was supplied. You cannot just place the components on the board, like a breadboard.
  2. You need to connect the Arduino pins to the IN side of the PCB connector once it is in place (one of the signals is called DIN or Data IN). The out side has DOUT.

Well just for the record I connected three grids and 3 max 7219 all on a bread board using jumper wires, with little to no difficulty (aside from a slight program error, which I might add, not even the masters out there noticed). I did however use the pins I got and put them on the grids, to lift it up, so I could get wires underneath.