[FOR SALE] expanded dmg button pcb (i2c version) [WORLDWIDE]

[kitsch-bent]

got these tested and in the shop today. they are essentially like the other button breakouts I've got in the shop, except they cut the required wires down to 4 instead of one for each button (plus the ground). useful if you want to free up some of the pins on your pi, or cut down on the amount of wires inside your shell

http://store.kitsch-bent.com/product/ex ... 2c-version





http://store.kitsch-bent.com/product/ex ... 2c-version

http://store.kitsch-bent.com/product/ex ... 2c-version

[Akina86]

hey Kitch, i ordered the current version board last night. i was wondering if this one works like a teensy built on to the board already. since it has four solder points i just figured it must work like a usb gamepad or something. keep up the awesome work, can't wait to see whats next.

[kitsch-bent]

hey Kitch, i ordered the current version board last night. i was wondering if this one works like a teensy built on to the board already. since it has four solder points i just figured it must work like a usb gamepad or something. keep up the awesome work, can't wait to see whats next.

not quite, the I2C protocol is generally used to cut down on the required number of wires to a part of a circuit, but its not a microcontroller. you can communicate to it through a microcontroller or similar (like the Pi itself). a microcontroller just to control a button matrix would be overkill, something like this is cheaper and just as effective, although perhaps less modifiable than a microcontroller but you don't need it to do very much. just read the button presses, and for doing that a microcontroller is really too much for so simple a task.

check out the datasheet for MCP23017, it will walk you through how to use this. the arduino code on the product page is a simple way to test it, and you can reference for how to address the IC (like how to turn on the pull-ups, for example)

[Akina86]

even better! thanks, i can't wait to give it a go!

[Akina86]

hey, just got the board today! thanks, that was fast! i wired it up and now my confusion begins. i am THE definition of a noob when it comes to the pi and i think i misunderstood your explanation of how this board works. i was hoping that maybe you could make a small tutorial on how to get this board set up.

just for clarification i wired up ground to the GND, 5v to VIN, GPIO pin 3 to SDA and finally GPIO pin 5 to SCL. i figured there was more to it on the pi side than simply hooking this up, but i tried it and yep, i need to do some kind of configuring and i'm kinda stuck. any help would be awesome and i am sure i wouldn't be the only one in need of your guidance. thanks in advance.

[kitsch-bent]

hey, just got the board today! thanks, that was fast! i wired it up and now my confusion begins. i am THE definition of a noob when it comes to the pi and i think i misunderstood your explanation of how this board works. i was hoping that maybe you could make a small tutorial on how to get this board set up.

just for clarification i wired up ground to the GND, 5v to VIN, GPIO pin 3 to SDA and finally GPIO pin 5 to SCL. i figured there was more to it on the pi side than simply hooking this up, but i tried it and yep, i need to do some kind of configuring and i'm kinda stuck. any help would be awesome and i am sure i wouldn't be the only one in need of your guidance. thanks in advance.

yep, some configuring is required. take a look on the product page, and you'll find some code for arduino there. this at least has all the addresses you need to get this thing going.

if you are using it like it was shipped, the IC is set to be 0x20.
you'll also notice in the code there are addresses mentioned for port A and port B, and in the setup part of the code it shows how to turn on the internal pull-ups.

and, of course, read all the ins/outs as inputs (for the button presses).

if for some reason you are using another device on address 0x20, you can remove the resistor and bridge the other one, and get it set to 0x21.

but some configuration is required. you are correct. but, a lot of the difficult work is done in that example code, you will just need to apply that general logic to your device and how you need to confirgure it on your Pi.

[kitsch-bent]

make sure you set the internal pull-ups, on both ports, to 0xFF. otherwise your readings will be very messy. this IC is nice in that they are available and it helps avoid needing other components on the PCB (like a bunch of resistors or whatnot)

[Akina86]

hmmm, crap. i got the file or script from the description on the product page, but i don't know where to put it or what to do with it. i think i'm in over my head on this one. i think maybe ill try to sort out the solder points on the previous board i got from you.

this is how i am feeling at this point ----v

[Akina86]

unfortunately for me, this is just how ignorant i am in this area. i have made it this far because wermy was nice enough to hold our hands step by step to this point, i'm just kind of forced in this direction because i didn't have an old gameboy to use for parts, i bought a repro case and been building from the ground up. i know how to ssh into the pi and add and remove and edit files, but i don't know where to put this script and if i need to edit it, i will be lost. i understand if you don't have the time to lay it out in simple terms, but i am sure i am not alone here and potential buyers might find a tutorial beneficial to make their choice as to what board is right for them.

[kitsch-bent]

unfortunately for me, this is just how ignorant i am in this area. i have made it this far because wermy was nice enough to hold our hands step by step to this point, i'm just kind of forced in this direction because i didn't have an old gameboy to use for parts, i bought a repro case and been building from the ground up. i know how to ssh into the pi and add and remove and edit files, but i don't know where to put this script and if i need to edit it, i will be lost. i understand if you don't have the time to lay it out in simple terms, but i am sure i am not alone here and potential buyers might find a tutorial beneficial to make their choice as to what board is right for them.

the code you are getting from the product page is for arduino, it is not the correct format for the Pi. unfortunately...

i'm a little hesitant to do a walk-through for this project, as its meant as a DIY addition, but mainly because wermy isn't using this in his guides and it will create a huge amount of confusion if there are multiple configs floating around and not a standard approach.

so, let me contact him later today and see if he'd be open to doing a more standardized install of this board that perhaps he could work into his guide as an option. i think that might be the best bet to avoid later confusion and keeping the project somewhat consolidated...