Arduino to MDB Interface as cashless device

Using Arduino General Electronics
1

Hello Guys,
I don't know why I cannot find enough result about Arduino with MDB (Multidrop bus) interface.
I just want a simple code to send a credit to a vending machine using Arduino Uno.
Is it very complicated?
There is no completed schematic/ wiring diagram also no coding enough.
Please if anyone can help.
Just a simple code to send credit to a vending machine using MDB interface.

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@malekses, your topic has been moved to a more suitable location on the forum. Installation and Troubleshooting is not for problems with (nor for advise on) your project :wink: See About the Installation & Troubleshooting category.

3

Which Arduino? There are several different versions.
Please post a link to the datasheet of the other hardware used.
Often the IDE examples contain code for starting. If not, try Google on "Arduino + 'Your hardware'".

4

Arduino Uno V3.
And I said that I'm new with Arduino, all what I need is a simple schematic diagram and a line of codes to send credit to a vending machine.
I tried to find something in google but I don't know why I cannot find any clear project or result.
any help can be appreciated.

5

Have You got any bus interface device already?

Explain what the communication will look like. One multidrop is Ethernet. I2C is another standard. What is the communication on the bus supposed to look like? Pen, paper and a logic block description might help us.

6

It MDB (multidrop bus) protocol for vending machine.

7

https://lmgtfy.app/?q=MDB+vending+machine+arduino&iie=1

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I know how to search in google, and I'm sure there is no result.
if you have anything to provide me like schematic or coding you are welcome.

1 Like
9

There was for me:

GitHub - LanguidSmartass/mdb-arduino-cashless: MDB Cashless Device implementation based on Arduino Uno and GPRS Shield. (References this protocol spec: https://www.ccv.eu/wp-content/uploads/2018/05/mdb_interface_specification.pdf )

Interface electronics:

https://256.makerslocal.org/wiki/Soda_Machine/Cashless_Device

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Thanks for your rich results, unfortunately all of them missing the diagram or code or both.
most of them not tested as per feedback especially the projects in Github.

11

Diagram:

Code:

The code uses the Serial hardware directly to allow the use of the 9-bit communication feature. I would recommend using an Arduino Leonardo (or Micro) so the Arduino can communicate with a PC via USB (Serial) while using the hardware serial (Serial1) to talk to the interface hardware to MDB.

NOTE: In this project, SoftwareSerial, is used to send the 9 bits of each received character to a second sketch on a second Arduino:

This sketch receives the 9-th bit as one 8-bit character and the other 8 bits as a second 8-bit character. It goes on to interpret the message. If you use an Arduino Leonardo or Micro, this sketch would be merged into the same sketch that receives the 9-bit characters.

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