Vender is free open source VMC (Vending Machine Controller). (fork https://github.com/temoto/vender) This software has been working since 2019 (small network of coffee machines.) equipment used: VMC: eVend8 (bill validators: JCM300 and ICT7, Coin validators: CoinCo Global2 and Coges Aeterna) Main Board: OrangePi Lite, additional display: 320x240 controller st7789v additional sound card: noname USB sound card

Status:

• MDB adapter hardware module - works
• VMC - works

Required for VMC:

• Works on RaspberryPI, OrangePi Lite (H3) OrangePi PC2(H5). Possibly anything with GPIO that runs Go/Linux.
• MDB signal current limiter - required, see files in hardware/schematic (https://namanow.org/wp-content/uploads/Multi-Drop-Bus-and-Internal-Communication-Protocol.pdf)
• MDB adapter, takes care of 9bit and timing, we use ATMega328p (168) with hardware/mega-firmware. (software option is available: https://github.com/temoto/iodin . in a similar solution, another author made measurements. delay may be up to 10ms. in the specification MDB the maximum delay is 5ms )

Supported peripherals:

• MDB coin acceptor, bill validator
• Evend MDB drink devices
• any MDB device via configuration scenarios (work in progress)
• MT16S2R HD44780-like text display
• TWI(I2C) numpad keyboard
• graphic display (anyone registered in the system.)

VMC overall structure:

• engine (see internal/engine packages) executes actions, handles concurrency and errors
• device/feature drivers provide actions to engine
• configuration scenario specifies action groups and when to execute them

• Install latest Go from https://golang.org/dl/ (now worked on 1.23)
• Set target environment, default is GOARCH=arm GOOS=linux
• Run script/build
• Deploy file build/vender to your hardware