MDB to UART: hooking up a vending machine to an Arduino

[swmmrmn]

I was hoping this forum might be able to give me some perspective on how easy/difficult it would be to hook-up a vending machine to an Arduino. I have a pretty solid background in programming (e.g. C, Java, etc), but basically no understanding of basic circuits and the different serial interfaces.

Based on the little bit of research I've done so far, it sounds like Arduinos use UART while most modern vending machines use a MDB-based protocol (the official vending machine standard can be found here: http://www.vending.org/technology/MDB_Version_4.pdf). It'd be great if the solution was as simple as connecting the proper pins from the MDB connector (see section 4, page 7 of the MDB PDF) to the appropriate pins on the Arduino, but I'm guessing there's probably more to it than that. Any suggestions or pointers to similar projects would be greatly appreciated. Thanks!

[Franklin97355]

4.4 example on page 56 seems to imply it will work with the addition of a transistor between the MDB and the Arduino.

[opossum]

Do want to do master or slave? The circuit is different for each.

[len17]

As to the data protocol, according to the MDB spec every byte has an extra "mode" bit so I don't think you can use the Arduino's Serial library to send & receive the data.

I think the Arduino's UART can actually handle 9 data bits but you'd have to program it directly, basically duplicating the Serial lib.

Alternatively you could use the digital I/O functions, like the SoftwareSerial library.

[swmmrmn]

Do want to do master or slave? The circuit is different for each.

I'd like to setup the Arduino as a slave.

[betocom77]

Did anyone happen to finish this project?