Expanding TONS of Switches/LEDs with Arduino (Teensy + ATtiny) and Controlling over MIDI! 

100.000 follower ! congratulation

Since you splurged for the Attiny carrier board.....could you have also just used Teensy LC boards at $11.65...? You could have then set up an 8 pin address on an 8 pin Dip Switch. So you would have 4 ins and 4 outs, 8 bit address for 256 units, I2C bus at 2 pins. That is 18 pins and the LC has 27 pins of I/O. Then you could just program them all the same....and use the Dip Switch to tell the chip what unit it is and what MIDI to use. Just another thought. Another possibility would be to use an Attiny84....or possibly an Attiny4313(maybe). Absolutely love your channel...and the Trigboard! Congrats on the 100k!

Huge scalability potential here! Nice. A thought: * I can't remember for sure, but I think most AVRs have a unique ID burned into them somewhere. * If that's the case, you could load the ATTiny boards with the same code at some default I2C address (perhaps the top end of your range). * The Teensy would then call out to that universal address, send the UID, and send the desired address for that UID. * ATTiny compares UIDs; if matched, set the specified address. * That way, any changes can be done from the Teensy code, which could simplify the management & maybe aid repair-ability later (should a board need swapping). * If you're really feeling fancy, you could have the ATTiny briefly display its assigned address once it's set for debugging (in four-bit increments of course). 😁

As the number of ATtiny's increase the latency of the button presses will increase. You could try and arrange the ATtiny’s in to blocks. Each block sends an interrupt on a key press, so you only need to process a block where there is button is pressed, this will reduce the number of reads to devices that have nothing to report.

Interesting! I have always considered i2c to be fairly slow but it looks like you got great performance. My initial thought for design would be to use a parallel bus to a bunch of io registers

Kind of crazy you can get a microcontroller for under a dollar which is as capable as the ATtiny1614.

I'd use a standard port expander as they're readily available. For large installations, an RS485 based bus like DMX (unidirectional) , CAN or MODBUS (bidirectional, used in industry) would be appropriate as it is very resilient to EMI. 4 in/4 out reminds me strongly of AS-i bus which transmits power and data on the same two lines, but is kinda slow and proprietary.

Interesting as always... An I2C booster chip close to the Teensy will help...like the LTC4311. For long distances rs485 is an alternative solution...

Nice. Have you checked the i2c on a scope? Perhaps you need a lower pullup resistor when you scale up. It could also be nice to have exactly the same sw on each node. Perhaps the node address could be kept in eeprom.

Dude fire. keep it up!

Have you heard about charlieplexing? You can use it for driving LEDS and even input with the original GPIO pluse few diodes. For large matrices, the design gets complicated layout-wise, but its worth checking as an alternative

Hey I really need some help with a project with leds. So i have this small replica of sky tree and it only got 3 color blue, red and pink. I want to change it up and make it connect to the razer argb controller so i can use it with the razer synapse app and make it work with the rest of my gaming setup. And i have no idea on how to make it work

Have you measured the power at all? I imagine that constantly looping means the idle power would be a little higher. What changes would you make in order to turn this into an interrupt-driven design rather than a polling design for the purposes of reducing overall power consumption?

I possibly missed it. Did you debounce the switches?

Nice solution. Was a simple matrix for both led and switches not an option? Wiring I guess would be more dense with a matrix and perhaps response time would be slower too. What was your thinking for not choosing a matrix arrangement?

great walkthrough. thanks for sharing. couple of questions. You walked through the NoteOff case... for NoteOn, is it the exact same code but with a "1" in the writeLED statements? If so, couldn't you just set a bool from NoteOff or NoteOn case and then run the same code? Also, do the buttons not need any debouncing? If not, i'm wondering why they don't. Awesome build!

Nice.

Comment at 3:00 I²C?? Daisy chain type of thing Edit: I was right!!

I knew it when you sleep you dream machine code LOL

Have you decided to use the Teensy instead an Arduino usb compliance ( like micro ) for the board price or of the libraries?

Did you took in concideration to use a simple MCP23017 ? Thats a great 16 bit I/O chip and rather cheap! It has interrupts on the pins too. It has an I2C and SPI verison as well! And if 16 pins arent needed you could have easily used an PCF8574 which is an 8bit I/o with I2c as well. I wouldnt go with your solution simply because it is too expensive for everyone who is not living in a rich country. There are much cheaper solutions. Of course if you can spare the money thats alright... I wouldnt go that path Edit: Ok I see you want to have a lot of separated button arrays. Most of the I2C chips are limited to 8 chips on a bus...

Look like Wintergatan machine

They call you the "Switchman"

20:17 have you heard of shifting bits? >>