I'm looking at doing a portable (battery powered) Tinyduino with 4x MAX7219's LED arrays cascaded. I'm new to all of this, and haven't done the math on the current draw of the 4x MAX7219 w/LED's yet. But I would like to know the best way to supply the power to them? I'd like to use the lithium ion that you can buy from Tinycircuits. But I don't think the 5V or Vcc from the Tinyduino supplies enough power for this. I assume I would need to have some sort of boost converter circuit to get to 5VDC. Can someone direct me on this?
Also, are the Tinydiuno I/O lines 5VDC or 3.3VDC? i.e. will I need some sort of voltage level converter to drive the I/O lines to the MAX7219?
If there is something better out there than the Tinydiuno and how I'm trying to do that, I'm open to suggestions.
Thanks in advance for the help.
ok. so did some digging, thinking of using the lithium battery that i can get from tinycircuits, for reference here is a link:
and use this wye connector:
and this boost board:
this allows me to supply power directly to the MAX boards and to the tinydiuno.
The only question (unless someone tells me the above plan is a bad idea or they have a better one, which I'm really open to) I have left is, if I supply the tinyduino with the 3.7V lithium battery, what is the voltage level of the I/O lines from the tinydiuno, i.e. do I need a voltage level converter like this:
voltage level converter board
I dont know anything about this 'Tinyduino' you refer too.. and you didnt provide any links for anyone.. so you can figure out the working voltage..etc.
I also think some research on the MAX chips will really help you understand some of your other questions as well..
The MAX chips multi-plex.. so that means the leds are not all on at the same time (even though your eyes cant tell the difference).. it basically turns on/off the led(s) so fast you think the leds are all on at the same time.
Each MAX chip will need a current limiting resistor.. which is the set current the led will get.
The max chips are great and easy to work with.. they do NOT support any PWM in a true sense.. but I do believe there are a handful of 'brightness' levels you can set (not individually though of course)..
Each MAX chip can control up to 64 leds.. and can be daisy chained together to control more.
Is there a reason you are wanting to use this Tinyduino? And at +3.3v? Grab a $2.00 USD Pro-Mini..
Tinyduino. I was kind of hoping someone here had experience with it:
And kind of looking at a MAX7219 array that is already preassembled:
LED array assembly
Where do I find a pro-mini for $2?
I though the tinyduino may be easier for my kids, since this is something we were going to do this together (I didn’t mention that before), and I don’t want 3.3V if possible, I’d like 5V…at least I think I want 5V since the assembly is 5V.
IMHO.. I would stay away form the Tinyduino stuff for now..
Its nice, if you need 'that'. Its basically set up to use proprietary shields that fit its dimensions.
I dont currently see any benefit from it in your project.
+5v, 16MHZ too..
I dont think anything would be easier than a Pro-Mini with headers on a breadboard.
The LED array looks fine to me.. (basically everything I explained but in an already made PCB)..
There is a pretty easy to use library for the MAX chips too.. LedControl lib I think its called?
There is a nice tutorial in the playground for using MAX chips too.. very informative.
One thing to keep in mind...
I'm not sure HOW you program the Tinyduinos.. but for the Pro-Mini's.. they USB port and the chip are removed.
So you need to use an FTDI/TTL to Serial type of programmer (its not a big deal.. they only cost another $2.00 if that.. and just connects to the 6 serial programming pins/header on the board.. and everything else is the same process in the IDE..etc)