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Week 5 Electronics Production
This week is a start of electronics. I am very excited about it. Circuit is brain of the systems. I know it will takes years to master.
Weekly Assignment
- group assignment:characterize the design rules for your PCB production process
- individual assignment:make an in-circuit programmer by milling and stuffing the PCB, test it, then optionally try other PCB processes
Group assignment:
Shayas did the group assignment link.
PCB fabrication:
Etching is traditionally the process of using strong acid or mordant to cut into the unprotected parts of a metal surface to create a design in intaglio (incised) in the metal.[
Lithography is a method of printing originally based on the immiscibility of oil and water.
SDS are materiel safetysheet.
Chemical way of PCB fabrication will waste a lot of water.
What is FabISP?
In-System programming (ISP), also known as in-circuit programming (ICP), it allows programming and reprogramming of microcontrollers, serial EEPROMs and flash memories already soldered on a target PCB.
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1 Obtain the files: Find a Circuit Board
Export/save your board design as .png, You should have two or three images, depending on your PCB:
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2 Set machine paths by Fabmudules:
Fabmodules is a online program to calculate the machine paths and set input and output to milling the board.
** 0.4mm Tolerance of Circuit Design: Circuit should have a gap of at least 0.4mm between each path/element on the board.
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3 Milling the board
Use double side tape for fixturing the board on underlay. Turn on Roland Modela and the computer and open VPanel for SRM-20,A nice tip is to warm the spindle for 10 min at mid Rpm before using it.
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Use“sacrificial board” so you don’t mill the own machine.Make sure it’s steady and flat.
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Change mill: 1/32 inch bit is for cutting out board,1/64 inch bit for milling trace; Set the X/Y/Z zeros; Send the traces and send the outcut/holes.Set XY ,and Z for end mill.
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4 Soldering the board
Use tweezers and brush to clean and remove glitch.Then soder components below:
- 1x ATtiny45
- 2x 1kΩ resistors
- 2x 499Ω resistors
- 2x 49Ω resistors
- 2x 3.3v zener diodes
- 1x red LED
- 1x green LED
- 1x 100nF capacitor
- 1x 2x3 pin header
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However, my first FAB ISP doesn't work somehow. Proberbly because my bad soldering.
First one: failed.
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Second one: I use a wider soldering iron which works better to solder chip. I also use solder paster that could help soldering tin stick to copper lines.I also use a multimeter to check for shorts between VCC and GND.
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4 Software Installation
- Set up development environment for my laptop. Download CrossPack CrossPack is a development environment for Atmel’s AVR® microcontrollers running on Apple’s Mac OS X, similar to AVR Studio on Windows. It consists of the GNU compiler suite, a C library for the AVR, the AVRDUDE uploader and several other useful tools.
- Download thefirmware source code
5 Get and build the Firmware
Download the firmware source code and extract the zip file
Connect ISP to laptop:
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