ccc-basel/matemat
6
0
Fork 0
Code Issues Pull requests Releases Activity

Overhauled readme and added protocol and wiring information

Browse source
This commit is contained in:
Gregor Riepl 2021-01-13 22:10:50 +01:00
parent 7fbd464daa
commit 2f7f80a885
1 changed files with 76 additions and 40 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

116
README.md
View file

@ -2,37 +2,33 @@
The Matemat is a vending machine for carbonated soft drinks. The Matemat is a vending machine for carbonated soft drinks.
It is based on an old vending machine with all its It is based on an old vending machine with all its electronics replaced by new
electronics replaced by new custom-build circuit boards. custom-build circuit boards.
All hardware and software was designed by members of All hardware and software was designed by members of
[CCC Basel](http://www.ccc-basel.ch) and released in the [CCC Basel](http://www.ccc-basel.ch) and released in the form of circuit
form of circuit diagrams, printed circuit board layouts diagrams, printed circuit board layouts and source code for anyone to use and
and source code for anyone to use and modify. Refer to modify. Refer to the LICENSE file for details.
the LICENSE file for details.
The name "Matemat" is a portmanteau of "mate" (as in mate The name "Matemat" is a portmanteau of "mate" (as in mate tea) and "automat"
tea) and "automat" (the German word for vending machine). (the German word for vending machine). The device is mainly intended to dispense
The device is mainly intended to dispense mate tea based mate tea based soft drinks, but may be used for other types of beverages too.
soft drinks, but may be used for other types of beverages
too.
## Structure ## Structure
The heart of the vending machine is a Raspberry Pi The heart of the vending machine is a Raspberry Pi model 3 or zero or later,
model 3 or later, witch a custom CAN interface board with a custom CAN interface board on its GPIO header.
on its GPIO header.
See [CAN Hat](https://github.com/onitake/canhat) for See [CAN Hat](https://github.com/onitake/canhat) for more information.
more information.
## Firmware ## Firmware
Some of the modules require firmware. There is a makefile in Some of the modules require firmware. There is a makefile in each module's
each module to build and flash it to its microcontroller. firmware directory to build and flash the firmware to the integrated
microcontroller
Before building, you need to check out the CAN driver Before building, you need to check out the CAN driver source code, which is
source code, which is referenced as a Git submodule. referenced as a Git submodule.
Run the following commands in the checked out repository: Run the following commands in the checked out repository:
@ -43,24 +39,22 @@ git submodule update
## Modules ## Modules
The Matemat components are highly modular. Individual The Matemat components are highly modular. Individual circuits are connected by
circuits are connected by CAN bus, and can be extended CAN bus, and can be extended as needed.
as needed.
### drive ### drive
Single-motor driver. Single-motor driver.
Attached directly to each bottle release mechanism. Attached directly to each bottle release mechanism. Requires only power supply
Requires only power supply wires for the motor and the wires for the motor and the CAN bus line.
CAN bus line.
### power ### power
Motor driver board and power supply. Motor driver board and power supply.
Alternative to the drive board. Uses the existing machine Alternative to the drive board. Uses the existing machine wiring instead of
wiring instead of power + CAN. power + CAN.
### control ### control
@ -70,23 +64,14 @@ Old central control board. Obsolete.
End switch feedback interface. End switch feedback interface.
Senses the status of the end switches and sends CAN bus Senses the status of the end switches and sends CAN bus messages on changes.
messages on changes.
### poweriface ### poweriface
Interface between CAN bus and power board. Interface between CAN bus and power board.
This module requires firmware. Switch into the firmware This module requires firmware. Connect an Atmel programmer to the ISP header,
directory `poweriface/firmware/` and run change into the firmware directory `poweriface/firmware/` and run:
```shell
make
```
To flash the firmware, attach a programmer to the ISP
header on the PCB, then run:
```shell ```shell
make flash make flash
@ -99,3 +84,54 @@ Environment sensor interface.
### wiring ### wiring
Wring schema of the old vending machine. Wring schema of the old vending machine.
## Bus
### Topology
All modules are connected via a CAN bus. It is highly recommended to wire them
by means of shielded twisted-pair cable with a nominal impedance of 120Ω.
At the very least, you need a cable with three wires to ensure a good ground
connection between all modules.
To allow for easy wiring, six-pole screw terminals are mounted to the PCBs.
Two poles are intended for the positive CAN bus line, two for the negative line
and two for the shield. They are internally connected together.
### Wiring
To achieve a continuous bus topology, connect only two cables to each module.
Make sure CAN H is connected to CAN H and CAN L to CAN L. Crossover is not
supported on the CAN bus. When wiring is complete, you should end up with a
continuous bus that is tapped at each module. Attach 120Ω resistors (preferably
1% or better) to the ends of the bus.
The final wiring should look like this:
```
┌───────────┐ ┌───────────┐ ┌───────────┐
│ module1 │ │ module2 │ │ module3 │
│ │ │ │ │ │
│H L ⏚ H L ⏚│ │H L ⏚ H L ⏚│ │H L ⏚ H L ⏚│
└╥─╥─╥─╥─╥─╥┘ └╥─╥─╥─╥─╥─╥┘ └╥─╥─╥─╥─╥─╥┘
╰━╯ └╥┘╱ └╥┘╱ └╥┘╱ └╥┘╱ ╰━╯
120Ω ║╱ ║╱ ║╱ ║╱ 120Ω
╚═════════╝ ╚═════════╝
```
### Protocol
Bus communication only makes use of basic CAN features. No higher-level
protocols such as CiA, EtherCAN, VSCP or similar are required.
Extended 29-bit CAN adressing mode is used.
This is the list of supported message IDs:
| Message ID | Sender | Receiver | Data Length | Data Format | Description |
|------------|------------|------------|-------------|-------------------------|-------------|
| 0x1000 | controller | poweriface | 1 | 0b00000MMM | Start dispensing from slot M (0-5) |
| 0x100 | any | poweriface | 0 | | Send power board status report |
| 0x100 | any | sensor | 0 | | Send sensor board status report |
| 0x10 | poweriface | controller | 2 | 0xLL 0xHH | Power board status report (0xHHLL are the contents of the 16-bit shift register) |
| 0x1 | sensor | controller | 2 | 0bABCDEFGH 0b00000IJK | Sensor board status report (ABCDEFGHIJK are the states of the end switches, dispenser empty switches and the rest switch) |