Friendly chat about vending projects

[mhaqs]

I stumbled upon this repository in search of open source firmwares for vending machines. I've skimemd through the source code a bit but cannot put a finger on what hardware this firmware is for. It'd be a good addition to the repo, to have a supported hardware profile or readme that explains, how to use this.

[endes0]

Its all made in go, so I think is for a Raspberry pi or similar.

[temoto]

@mhaqs we run on RaspberryPi. It could be virtually any machine supported by Go. Readme is a must, of course. I understand it's a bad reason, but didn't put much effort into documentation because it's early development stage. Hold on, I am committed to make this work publicly useful.

Dependencies:

• Go supported arch
• MDB requires soldering even with software choice below or we can talk about manufacturing
• • Custom hardware device (with ATMega328) -- best option so far, both schematics and code is available in this repo.
• • GPIO bit-banging -- works, thanks to pigpio library, MDB latency is half of maximum (5ms) per spec, maybe latency can be fixed with kernel scheduler settings.
• • With Linux kernel 4.9+ it's possible to do 9bit serial using termios -- easiest, but least reliable option. MDB latency is 4ms, close to max per spec (5ms). I've seen good report on stackoverflow about USB-serial hardware module with async_low_latency flag. That flag did not affect built-in UART in Raspberry1.
• 4 GPIO pins for MT16S2R like display driver (as of 2018-09 in development)
• TWI (I2C) for a numpad keyboard

Updated 2019-02: MDB external hardware module is our best choice again.

[mhaqs]

@temoto It's good to know the project's active and you're maintaining it. May be this project could help: http://eliverse.com/wiki/index.php?title=Programming_Vendiverse_VMC_Board?

I know it differs in many respects but I've been meaning to work on a generic firmware myself. I'll go through the repo and see if I can contribute something. This is one of the primary reasons why I wanted to know the project's goal or architecture.

[temoto]

@mhaqs do you know how to see their sources? I couldn't find it with a quick look.

[mhaqs]

I was able to scrape the following files:

http://eliverse.com/downloads/vendiverse/software/ENV/ENV.ino
http://eliverse.com/downloads/vendiverse/software/MDB/MDB_STABLE.ino

The last one found here: http://eliverse.com/wiki/index.php?title=Vendiverse_MDB_Module

[temoto]

Thank you.

[mhaqs]

Just so if it helps you @temoto , I looked into the armbian image on the vendiverse website, and it has the python source code. I'm attaching it here, so you don't need to download the whole image.

https://drive.google.com/file/d/1Heywm-dtGibz40IBfigaMmpYiOhnLkyE/view

[temoto]

Thank you. What was interesting to me is references to hardware they used, NFC reader MFRC522 in particular.

[mhaqs]

I think the differences come from using I2C as preferred communication method with the other hardware. The choice of RFC522 might also be because of that.

[azonicdh2000]

@mhaqs Have you tried making the Vendiverse vmc board?

[mhaqs]

@azonicdh2000 I haven't. I have instead been working on a pi3/udoo equivalent with arduinos instead. It was a bit hard to copy everything vendiverse offers.

This is why I like the approach vender takes. The vmc software should be able to cope with the hardware at offer. However, a configuration of the hardware would be great to start with. I've seen some hardware schematics posted on this repo by @AlexTransit. I will contribute some hardware and software knowledge as well in the near future.

What are you looking for @azonicdh2000? We can move the discussion else where as well.

[temoto]

The key takeaway from Alex schematics is UART-MDB converter. It is optoisolated logic level 3.3-5V switch with level inverter on one line, as per MDB spec. It works, use it. Huge thanks to this person http://blog.bouni.de/2012/the-mdb-protocol-part-1.html

As of 2018-11-22 vender has (maybe alpha-beta) support for MDB coin changer and bill validator. Right now we work on drink preparing devices, and overall "kitchen" codebase, like recipes. Next step is user interface after which we'll have something to show and talk about.

[azonicdh2000]

@mhaqs I’m trying to create the Vendiverse vmc board. So which part of the vendiverse was a bit hard to copy? Was it the main vmc board or tray board?

Yes maybe we should move to another discussion for vendiverse.

But I will try to look at vender.

[azonicdh2000]

@mhaqs were you able to obtain all of the files of vendiverse? If so can you share it with me? Thank you. My email add is azonicdh2000@yahoo.com

[mhaqs]

@azonicdh2000 The vendiverse website is now down, but I've hosted the contents here: https://github.com/mhaqs/vendiverse. You may move this discussion over there as well.

The vendiverse project does not talk about the motor control matrix. So, to answer your question, and to help with this project, I found this:

https://github.com/CCHS-Melbourne/vend-matrix

It shows, how you can use continuous motors in a matrix and to sense a low current to finish a vend. cc @AlexTransit , if that helps.