Hi All,
I just got myself 2 Max7219's with PCB, comps, etc from China very cheap!! But it's the sketch or even any of the sketches in the Arduino IDE that fail to compile or upload. In all three sketches I get MD_MAX72XX does not name a type, and as I am very new to The Arduino and especially C there's lots I can't follow. It seems the code will run for either device (Max7219/21) but think it may need some user input to say which??
Perhaps somewhere I need to alter MAX72XX to MAX7219? Test on the circuit seem to confirm there's no problem there!!
Here's the code but it's straight out of the IDE so you should have it! I think.
Well it seems the code is too long and I can't show it, which might make this all a bit pointless, HELP!!
Hi,
I've been storing chips in Stryrofoam for 30 years, all chip pins are at the same potential, so there's no potential (Danger) if you see what I mean!!
OK hopefully here's the code in the form of a file.
The max72xx library should work with your cheap Chinese type matrix units. It would help me if you can say what the exact error message is? IDE version would also be helpful, as the libraries will only work for v1 onwards.
On the surface it sounds like the libraries are not properly installed.
Sorry for my concussion, found the library and was able to compile all three (3) examples, sounds like your folder (ex. MD_MAX72xx) is not in your Library folder.
The landing page for the libraries at the code repository tells you how to install the library
For the Arduino IDE to be able to find and use them, these libraries should be uncompressed and placed in a libraries subfolder of your sketchbook folder.
1.Download the compressed (zip) file from the Downloads section (above).
2.Find or create the libraries subfolder of your Arduino sketchbook folder.
3.Uncompress the zip file in the libraries folder, keeping each library in its own unique folder.
CrossRoads:
Stryrofoam like that also generates a lot of static electricity, you're lucky that didn't zap the part.
I've gotten several shipments of parts in Styrofoam like that, especially LED matrices. I got several 74LS series chips sent to me that way by ebay sellers also. That never pleases me to see that.
Chips like the 74Ls are TTL chips and are quite safe in styrofoam as is the LED matrix. However the pins are not all at the same potential because the styrofoam is an insulator.
It is not good to store CMOS chips like this.
However there is a form of this packaging that has a conductive coating, it normally has a very smooth plastic feel to it.
Hi Edward,
Yes that kit is just the same as mine, but you have a nice coloured PCB, mines boring green. And again you were right the library was not where it should be!! I suspect this is a mistake I will make again.
But thanks to every one I now have them working, but getting both working together?? Sure one of the sketches does that.
Just to show I also keep some Chips in the right stuff here's a pic, Yes mostly my old TTL stuff is in polystyrene Covered in tinfoil "Styrofoam" what is that??
Thanks again and again, hopefully problem solved...
Yes mostly my old TTL stuff is in polystyrene Covered in tinfoil "Styrofoam" what is that??
As you might have guessed is is what the Americans call "expanded polystyrene". Just as we tend to say simply polystyrene when we actually mean expanded polystyrene.
Polystyrene in it's unexpanded state looks like tiny balls of glass, it is transparent and expands greatly on heating. When I was a kid in the 60s there was a Phillips Plastic set that contained polystyrene and a mould of a motor boat as a two part die-cast metal shell. You put a small amount of polystyrene beads in, clamped them together and put them in the oven.
But thanks to every one I now have them working, but getting both working together?? Sure one of the sketches does that.
In the MAX72xx examples, there is usually a NUMDEVICES define that tells the system how many matrices are joined up. Change that and make sure that the two matrices are joined together properly and you should see something.
Grumpy_Mike:
Polystyrene in it's unexpanded state looks like tiny balls of glass, it is transparent and expands greatly on heating.
Well, strictly, polystyrene does not expand on heating, but the material used to produce "Styrofoam" contains a dissolved volatile hydrocarbon (previously, nasty chlorofluorocarbon as in your example) which when heated, turns to gas and expands or "forms" the molten polystyrene itself.
Hi Mike,
I did'ent really need "Styrofoam" explaining to me, it was my poke at Americanisums!! The foaming part makes sense! Apologies to all our friends in the US, but it seems at times the World defalts to US style.
OK it did pass my mind that it was a bit ironic but on this forum we always try and answer questions at face value because some times people genuinely don't know something especially a cultural thing like that.
As to demurring to Amaricalisims well you have to because the poor people can't actually speak English.
I was writing a book and used the term Blow Torch and got jumped on by my editor who hadn't a clue what it meant.