Asked
— Edited
I'm really sort on digital ports on my rad project. I don't have any more digital ports left. I don't want to spend +$10 on a tip circuit because that wont allow me to turn individual leds on and off. Is there an alternate way I could power them?
Second EZ-B.
Multiplexer circuits.
A second EZ-B is the ideal choice. It's simple and supported by ARC's built in controls.
I2C Expander is next best but you will need to use scripts and you will need to find an expander that is well documented with all of the I2C commands you'll need to use to enable outputs.
Multiplexer is not really recommended, they cost a lot of ports to increase by few. They have been discussed and the conclusion was they are not really a good solution for increasing digital outputs.
Look around for parts for the TIP circuit too, $10 is a lot for the few items it needs. You should easily be able to pick up what you need to make one for $3 (plus any shipping if applicable).
@rich, already out of money in my budget so a second ez-b is out of the question. i2c scares me. I've looked at the commands and examples and it seems overly complicated.
I guess i'll wait until I've got the rad torn apart until I ask the questions.
I2C is pretty simple once you get past the initial "wow, what in God's name do I do with this" part. I was planning to use I2C extenders on Melvin's eyes before his head change to power and sequence rows of LEDs to simulate eye lids opening/closing (I've since found out that Loki has something very similar).
Besides, even if I2C does scare you, there's a community here waiting to help if you need it.
Let us know what you had in mind.
I've doubled up LED's connected to the EZB just to keep simple, but it all depends on your plan.
Kris
Or like myself, always said to my two daughters , if the request was valid(in our opinion) to provide half of the financing and the young person provide the other half. That means finding 40 dollars from cutting grass or....raiding you Uncles empty bottle stash and returning them for deposit values.......Thats just a few creative financing ideas.
Did I ask......when is your birthday coming up?
@Kudo's method of multiplexing could work but it would be a lot of data being passed from PC to EZ-B. Considering you have a limit of how much you can send and receive in one second fast switching of ports to enable multiple LEDs would be a real strain on that and has a very high possibility of bottlenecking the communications (after all, a 5 x 5 matrix would have 25 very fast port switches required, best case scenario is 250ms timings which is 100 commands per second, benchmark shows it's capable of 40-50). As I said originally, multiplexing was mentioned before and concluded as being a bad idea. I may knock up a test at some point with a 3 x 3 matrix, 4 x 4 matrix and 5 x 5 matrix and test to see if it provides acceptable results - it's another thing added to the ever growing list
And there's also that 2 pin plug above D14.
The +5 and Ground of the digital track should also work if you really wanted to use them.