DREAM-PI

DREAM-PI is a device that provides PubNub interfaces https://www.pubnub.com/ to barcode reader, balances, and NFC reader/writer.

Description

DREAM-PI is a device that provides PubNub interfaces https://www.pubnub.com/ to barcode reader, balances, and NFC reader/writer. As of January 25, 2018, we use computer (Raspberry Pi) as an infrastructure.

As an example of applications of DREAM-PI, we develop a web interface named Imoko. He transfers quantity of a specimen weighted in balance into Medusa using DREAM-PI.

As of January 19, 2018, one computer (Raspberry Pi) can communicate with two balances and one barcode reader at once.

Principle

Specimen-ID is delivered from barcode reader to Imoko (web interface) and Medusa via following path.

• CR 3500 (barcode reader) [bluetooth] DREAM-PI (pub_rfcomm.js)
• DREAM-PI (pub_rfcomm.js) [PubNub] Imoko (web interface)
• DREAM-PI (pub_rfcomm.js) [TCP/IP] Medusa

Quantity of the specimen is delivered from balance to Imoko (web interface) and Medusa via following path.

• MS 16002S (balance) [RS232C/USB] DREAM-PI
• DREAM-PI (weigh.js) [PubNub] Imoko (web interface)
• DREAM-PI (weigh.js) [TCP/IP] Medusa

To ensure reliable connection between DREAM-PI and Bluetooth, we encourage an user to restart DREAM-PI before operation.

Operation

1. Open Imoko (web interface) http://devel.misasa.okayama-u.ac.jp/io/.
2. Click Start to reboot DREAM-PI.
3. Scan connection code to hear beep twice.
4. Scan specimen-ID.
5. Put a specimen on a balance.
6. Push Weigh button. Confirm if quantity was updated.

Barcode reader

As of May 24, 2017, Code CR 2500, CR 3500 and CR 2600 are supported. Note that before for the first connection, authorization is required for each device.

Balance (METTLER TOLEDO MS1602S)

Enable HOST mode to communicate using RS-232C.

Balance (AND FG-30KBM)

Enable COMMAND mode to communicate using RS-232C.

Computer (Raspberry Pi)

Overview

Computer (Raspberry Pi) talks to barcode reader and balances via device files of Bluetooth and USB, to channels by PubNub, and to Medusa via TCP/IP.

• Barcode reader: Via device file /dev/rfcomm0, computer (Raspberry Pi) receives specimen-ID from barcode reader through Bluetooth and publishes it to PubNub channel-a. Via TCP/IP, computer asks Medusa to solve specimen-ID.
• Balances: Via device files /dev/ttyUSB?, computer (Raspberry Pi) receives weight from balances (METTLER TOLEDO MS1602S or/and AND FG-30KBM) through RS232C and publishes it to PubNub channel-b. Via TCP/IP, computer updates quantity of a specimen with the specimen-ID on Medusa.

Configure services

Install and activate services as shown below. Revise configuration file (/srv/nodejs/config/default.yaml) when necessary.

$ lsb_release -a
Distributor ID: Raspbian
Description:    Raspbian GNU/Linux 8.0 (jessie)
Release:        8.0
Codename:       jessie
$ git clone https://github.com/misasa/dream_io
$ cd dream_io
$ sudo cp -r ./nodejs /srv/
$ sudo cp /srv/nodejs/config/default.yaml.example /srv/nodejs/config/default.yaml
$ sudo cp ./udev/rules.d/rfcomm.rules /etc/udev/rurles.d/
$ sudo apt-get install nodejs npm
$ sudo npm cache clean
$ sudo npm install n -g
$ sudo n stable
$ sudo ln -sf /usr/local/bin/node /usr/bin/node
$ node -v
v9.2.1
$ sudo apt-get install libbluetooth-dev
$ cd /srv/nodejs
$ sudo npm install
$ sudo cp ./systemd/system/nodejs_rfcomm.service /etc/systemd/system/
$ sudo cp ./systemd/system/weigh.service /etc/systemd/system/
$ sudo cp ./systemd/system/weigh_console.service /etc/systemd/system/
$ sudo systemctl daemon-reload
$ sudo systemctl enable nodejs_rfcomm.service
$ sudo systemctl enable weigh.service
$ sudo systemctl enable weigh_console.service
$ sudo systemctl start nodejs_rfcomm.service
$ sudo systemctl start weigh.service
$ sudo systemctl start weigh_console.service

Configure USB-RS232C connection

The balances should talk to the computer by USB via RS232C. A RS232C-USB converter (REX-USB60F) should be installed.

Name of the USB device file is temporal and fragile. To talk to the balances, make a symbolic link to the device file dynamically, and refer to the link instead of the device file from application.

$ sudo vi /etc/udev/rules.d/99-usb-serial.rules
$ cat /etc/udev/rules.d/99-usb-serial.rules
SUBSYSTEM=="tty", ATTRS{idVendor}=="067b", ATTRS{idProduct}=="2303", SYMLINK+="balance0"
SUBSYSTEM=="tty", ATTRS{idVendor}=="0584", ATTRS{idProduct}=="b020", SYMLINK+="balance1"

Example of configuration file

$ cat nodejs/config/default.yaml
config:
  pubnub:
    publishKey: "demo"
    subscribeKey: "demo"
  medusa:
    url: "http://dream.misasa.okayama-u.ac.jp/demo/"
    auth:
      user: "admin"
      password: "admin"
  tepra:
    url: "http://172.24.1.121:8889/"
    printer: "KING JIM SR5900P"
    template: "18x18"
  balance:
    - name: "METTLER TOLEDO MS1602S"
      port: "/dev/balance1"
      options:
        baudRate: 9600
      delimiter: "\r\n"
      command: "S\r\n"
    - name: "AND FG-30KBM"
      port: "/dev/balance0"
      options:
        baudRate: 2400
        dataBits: 7
        parity: 'even'
      delimiter: "\r\n"
      command: "Q\r\n"

Imoko (web interface)

Imoko (web interface) monitors a specimen message via TCP/IP on PubNub channel a, that consists of ID and name, and shows the specimen ID and the name.

Imoko (web interface) reads a weight message via TCP/IP on PubNub channel b when Weight button is pressed, and shows the weight.

Then Imoko (web page) asks computer (Raspberry Pi) to update the weight of the specimen on Medusa.