LAOS I2C Panel v03 » History » Revision 19
Revision 18 (jaap, 2012-11-09 08:23) → Revision 19/24 (KalleP, 2012-11-22 23:00)
h1. LAOS I2C Panel v0.3
{{>toc}}
!>Panel-rev0.3.jpg!
%{color:red}This page needs to be cleaned up!%
h2. Basics
We designed a panel with a 2x16 LCD, 4 buttons and a joystick. The heart of the panel is a ATMEGA168-20PU running a small Arduino program. The panel uses I2C communication to the MBED board, but there is also a connection for a standard USB->TTL cable. You can use such a cable to upgrade the program in the Arduino chip.
All the source files of this project are available in the i2c panel project on Github: https://github.com/LaosLaser/AddOns
h2. Functionality
The user interface _The functionality is not implemented in this board, but in the program on the MBED. The on board ATMEGA with Arduino code only receives data for displaying on the screen and sends key press codes keys via I2C, basically this works as a tiny terminal. I2C. The functionality as is stated here is just to show what the main LaOS controller board uses it for. will do_
While no job is running:
* Manual manual focus, using up and down buttons (for some machines this will mean that the Z-axis is moving, others will move the lens-holder up and down)
* Moving moving the head to a specific location (jog in the X and Y (X-Y axis)
* Select select the current location and make that the origin (x=0, y=0, z=0)
* Select select print job
While a while job is printing:
* Pause current job
* Resume paused job
* Cancel current job pause printing / continue / cancel
h2. Electronics
We designed our own board and software (Arduino (arduino based) to connect the display board to the mainboard (via I2C interface). I2C). The schematics (in KiCAD) are located ["here":https://github.com/LaosLaser/AddOns].
Most important parts:
"Full part list is available in GIT":https://github.com/LaosLaser/AddOns/raw/master/i2c-panel/pcb/bom.ods
* 16x2 "16x2 LCD Display, RS stocknummer 532-6408
* ATMega168P-20PU, RS stocknummer 696-2430
* 4 Pushbuttons pushbuttons
* 1 Joystick joystick button
* and of course, the PCB board
!173px-Panel-rev0.3front.jpg!
h3. Bill of Materials
|_.Number|_.Component|_.RS Part No.|_.RS Price|_.Farnell Part No.|_.Farnell Price|_.Comment|
|1|LCD display, 16x2 characters|532-6408|€ 4,62| | ||
|1|ATMega168P-20PU|738-0375|€ 5,22|1636933|€ 4,81||
|4|Thru hole tactileswitch12x12x7.3mm|378-6763|€ 0,46| | ||
|1|PCB Stick switch, 4 dir + centre push|516-316|€ 2,46|1435775|€ 2,47||
|1|Ceramic resonator THT CSTLS 16.00MHz|526-6154|€ 0,56|1448129|€ 0,46||
|1|28way low profile DIL socket,0.3in pitch|801-768|€ 0,24| | ||
|1|100uF capacitor|711-0703|€ 0,03| | ||
|2|100nF capacitor|721-5240|€ 0,07| | ||
|1|680R resistor|707-7656|€ 0,02| | ||
|1|10K resistor|707-7745|€ 0,02| | ||
|1|36 way straight header,7mm top 3mm below|251-8632|€ 0,31| | ||
|1|NPN transistor,BC547C|545-2248|€ 0,07| | ||
|3|plastic buttoncap black|378-6943|€ 0,11| | ||
|1|plastic buttoncap red|378-6937|€ 0,11| | ||
|1|Eurocircuits PCB E412106| |€ 7,50| | |Available from LaOS (see [[WebShop]])|
h2. Mechanical construction
* PCB printboard is positioned directly under the display
* I2C communication is i2c through a 4-pin flatcable with pin-header
* A 6-pin (USB->TTL) USB->TTL connector is available for easy updates of on the Arduino
* 4 standard pushbuttons
* 1 Joystick 3D-printed joystick button (with 3D printed key cap)
The design files for a the frontpanel and buttons can be found here: ["Frontplates":https://github.com/LaosLaser/AddOns/tree/master/i2c-panel/frontplates]
h2. Implementation
The Arduino software on the ATMEGA arduino chip is "available on github":https://github.com/LaosLaser/AddOns/raw/master/i2c-panel/firmware/lasercutterpanelv0_3.pde. in GIT":https://github.com/LaosLaser/AddOns/raw/master/i2c-panel/firmware/lasercutterpanelv0_3.pde.
The electronics are based on "John Crouchley's ATTiny2313":http://john.crouchley.com/blog/archives/612 implementation. The Arduino (or Ottantotto) electronics come from "Edwin Dertien":http://wiki.edwindertien.nl/doku.php?id=boards:ottantotto:start#pin_description.
Relevant Arduino libraries:
* LCD driver: "http://www.arduino.cc/en/Reference/LiquidCrystal":http://www.arduino.cc/en/Reference/LiquidCrystal
* i2c: "http://www.arduino.cc/en/Reference/Wire":http://www.arduino.cc/en/Reference/Wire
* Keypad: "http://www.arduino.cc/playground/Code/Keypad":http://www.arduino.cc/playground/Code/Keypad
I2C on the Mbed: "http://mbed.org/handbook/I2C":http://mbed.org/handbook/I2C <em>"Have a look at this very enlightning drawing!":http://mbed.org/media/uploads/ColonelPewter/i2c_001004.gif</em>
For debugging, you can use any PC with a home-made I2C adapter:
p(((. http://www.instructables.com/id/Worlds-Cheapest-I2C-I-Squared-C-Adapter/
http://www.paintyourdragon.com/?p=43
h2. Building your own
To make life easier, we sell premade PCB's and this panel as a kit. See the "WebShop":/index.php/WebShop.
The kit contains:
* PCB
* ATMEGA168-20PU, pre-programmed with the Arduino bootloader and this I2C program (so you can install it even if you do not own a USB->TTL cable).
* LCD
* other electronic parts
* Buttons
* I2C wire to motherboard
Parts it does not contain:
* Laser laser cut panel. You can make one on your laser, maybe? Probably you want one to fit into your machine, anyway. See below for the panel the MiniFabLab made for its HPC LS3020
* 3D Printed printed joystick button. When I design one I'm really proud of, I might include it.
Feel free to make the user interface panel yourself if you prefer. No need to buy stuff if you have an Arduino lying around with LCD and some buttons!
h2. Soldering
* Solder the socket foot for the Atmel IC Arduino first, making sure the notch is on the same side as the one on the silkscreen legend. print.
* Place the two resistors. The print says 680 (Ohm) for R1. Resistor 1, which means 680 ohm. Put the other another one of 10k Ohm in the place marked R2.
* Solder the two 100nF capacitors
* Solder the 100uF electrolytic capacitor with the plus (longer) wire in the square hole with square solder pad
* Bend the wires of the BC547C so it lies it's flat on the print and solder in place
* Solder Place the 3 pin ceramic resonator filter
* Place a 2-pin header in P7, a 4-pin header for I2C and a 6-pin header in P1 (TTL).
* Now take a 16-pin header and push it with the longer pin ends long side in the PCB board from the bottom (solder) side back of the board. The long pins will stick out on the top side of the board. The On the back is the black plastic of the header in now on the bottom of the PCB. header. Measure with the display module to see if the pins are long enough to go just through the module. Solder the 16-pin header to the board on the TOP (component) side. side of the board (where the rest of the components is).
* Place a strong piece of tape on the bottom back side of the board, covering the part of the board that will be under the display module, so that there cannot be any shortcircuit shortcut between the board and the display module. You can use electric shielding tape or gaffer tape.
* Solder the display module on the back side board, with the black strip blocks of the 16-pin header in between.
* Solder the 4 buttons to in the board (not the joystick yet!) with the buttons on the side of the display (solder side). display. This is confusing: the buttons go on the side where it does NOT say button! See photos.
* The joystick has a very small dent in the top metal layer. If you put the joystick in, this dent should be on the right side. Solder it in.
* The holes you have left are for making wire-bridges on a single sided board. You don't need them.
Back panel
!I2CPanelBack-rev0.3.JPG!
Front Panel showing dent in joystick
!I2CPanelFront-rev0.3.JPG!
Showing connection on the I2C Panel side
!I2CPanelBankConnector-rev0.3.JPG!
Showing connection on the Main Board side
!IC2PanelConnectedToMainBoard-rev0.3.jpg!
h2. Software installation
h3. Installing a bootloader
These instructions are for ATMEGA168P-PU only!
cd arduino-1.0.1/hardware/arduino/bootloaders/atmega
avrdude -p m168p -c usbasp -F -U flash:w:ATmegaBOOT_168_diecimila.hex -U hfuse:w:0xdd:m -U lfuse:w:0xff:m -U efuse:w:0xf8:m
Note that the Debian version of avrdude does not support m168p yet, you can use the avrdude version shipped with Arduino.
Error message while installing:
avrdude: safemode: efuse changed! Was f8, and is now 0
Would you like this fuse to be changed back? [y/n]
Answer n !
h3. Arduino Sketch
Use a USB=>TTL cable to connect the board to your computer. Install "Arduino":http://www.arduino.cc software. Get "lasercutterpanelv0_3.pde from GIT": https://github.com/LaosLaser/AddOns/raw/master/i2c-panel/firmware/lasercutterpanelv0_3.pde
To test your panel, change:
#define DEBUG 0
to
#define DEBUG 1
Arduino settings: Board: Arduino NG or older with Atmega168
Upload the file to the board. This will give you a welcome text. After the text has disappeared, all buttons should show a number on the screen. The joystick should show 5 different values for each direction and middle push.
If it works, upload the code again with *DEBUG 0*. The panel is now ready to be connected to the mainboard.
h2. Control Panel on the HPC LS3020
To accomodate the display you can cut a replacement for the control panel.
!greenpanel-bart.jpg!
The button laser switch was replaced by a toggle for better on/off reference. So the right serial test button could be omitted. Also the lighting switch was removed, now the light is always on. No modifications are required for the cabletree, just connect the wires from the removed switches. The air pump switch was kept as a compressor can be noisy. It is advised to use a shielded cable between the I2C panel and the board. A cutting file (.svg) of this panel is available on "miniFabLab":http://minifablab.nl/uploads/LaOS3020panel.svg.
h2. Design competition
I couldn't find a fitting existing joystick button for the joystick in this design, so I made one on the 3D printer. But I'm not entirely happy with it yet. If you design a better one, please upload it here!
h2. Enhancements
Possible enhancements to the display:
* Make (I2C) connector holes slightly larger to be able to mount JST connector (also, some more clearance to micro controller is required)
* Larger larger holes also for USB->TTL cable, cable and display and switches
* Move move capacitor U4 to a safer place, near micro controller
* Holes holes for R2 are too big and texts for resistors are strange
* Mark mark clearly on the board that the buttons go on the back side!
* Add status LED(s)
* Buzzer? buzzer?
* Rotary encoder for (power) settings
* Graphical touch-screen display?
h2. More
For links on previous versions and to get started on designing your own display, see the [[Display-alternatives]] page.