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Making PCB


PCB design

Please read this page: Kicad for more information on KiCAD, there are more tutorials in Internet like [1] [2], also please read the README of fped about how to create a footprint for the chip you using. since we are making the board at home. try to using more width track and bigger via, if you plan to drill the vias manually, try to using more bigger vias, like > 0.5mm. if you are going to create a double-sided PCB, try to include some reference points that match on both sides. a '1-PIN' is a better choose.


Printer issues

  • If you try to print >240g photo paper. it may stuck in laser printer;
  • DO NOT USE photo paper that have glue-stuff at back. mostly >260g photo paper have that layer at back;
  • 600x600DPI: same width track on X/Y dimensions give different width;
  • 600x600DPI: somewhere got short

Paper details

Order by best --> better --> bad

Brand type Status Transferring Etching Memo


PRODUCT: B604200

A4 200g

Works fine

  • Toner looks very good
  • PCB thick: 0.8mm
L200g.JPG Etching-pcb-1.JPG shop

Photo Paper High Gloss

PRODUCT: CAT 5740-308

A4 180g 230microns 9.1mil

Works fine

  • Without toothbrush give pretty good result;
  • PCB thick: 0.8mm
K180g.JPG Etching-pcb-2.JPG shop

Photo Paper High Gloss

PRODUCT: CAT 5740-333

A4 200g 255microns 10mil

Works fine

  • PCB thick: 1.6mm
K200g.JPG Etching-pcb-3.JPG shop

Golden Professional Photo Paper

A4 240g

Works fine

  • PCB thick: 0.8mm
JD240g.JPG Etching-pcb-4.JPG shop



A4 240g

Works fine

  • PCB thick: 1.6mm
Lgg240g.JPG Etching-pcb-5.JPG shop


A4 200g

Not working

  • Toner removed when clean the glossy layer
D200g.JPG shop



A4 180g

Not working:

  • glossy layer hard to remove

Photo Paper

A4 190g 0.234mm

Not working

  • glossy layer hard to remove

Premium Photo Paper RC Gloss

PRODUCT: CAT 5740-329

A4 270g 273microns 10.8mil

Not working:

  • There are glue-stuff on back;
  • Clothes iron will melt the back;
  • Water can not remove the paper-layer;
  • Glossy-layer very thick and strong;
K270g.JPG shop


A4 260g

Not working:

  • There are glue-stuff on back;
  • Clothes iron will melt the back;
  • Water can not remove the paper-layer;
  • Glossy-layer very thick and strong;
L260g.JPG shop
3M Transparency Film A4 PP2910 100sheets

Not working:

  • Toner transfer not happen at all
Moverhead.JPG shop
OAego Professional transparency

for photocopy and laser print

A4 XC2910 100sheets

Not working:

  • Toner transfer not happen at all
Same as 3M film shop
Impression of the mood


A4 230g

Not working:

  • This is double-side photo paper
Impression of the mood

TransMax thermal transfer paper

A4 light-colored (浅色)

Not working:

  • Laser printer will melt the glue;
  • It may break your laser printer;
Impression of the mood

TransMax thermal transfer paper

A4 dark-colored (深色)

Not working:

  • Laser printer will melt the glue;
  • It may break your laser printer;

Photo Paper High Gloss

PRODUCT: CAT 5740-323

A3 230g 300microns 11.9mil

Not test yet shop

Plot KiCAD design out

After you finish your design, we need plot the top/bottom layer out. remember always using PLOT. we need mirrored output for sure. I am making a 2-layer board. the whole bottom layer is GND. so I only need to plot the top layer, it will be named in KiCAD.

Connect your printer, don't put photo paper in the printer tray, we have to use the manul feed. make sure you print the design on the glossy side of the photo paper, remember the output MUST BE MIRRORED, you will get your design on photo paper by using this command:

pcbnew --plot=ps --plot-fill-all-zones --layers=Front --plot-mirror PROJECTNAME.brd #requires our Qi KiCAD patches

Now we have the paper with a design and a bare copper board. now it's time for toner transfer.

Toner transferring

Clean the copper board

Using the steel wool remove the oxide layer that builds on the entire surface, the fine steal the better. make sure it is shiny. then clean the surface with a cloth. scrub the copper side until the copper is shiny and clean. DO NOT TOUCH the surface once the cleaning is done.

Start toner transferring

Cut out the design from photo paper, cut the copper board base on your design, set the clothes iron to its highest, (no water inside, no need stream)

  1. Preheating the copper board, place a white paper between the copper board and iron. this is for iron don't dirty the copper.
  2. Place the photo paper design to the copper board. alignning it properly, with the toner facing down. it will immediately stick to the copper board. so make sure it is alignning right. you cannot move the photo paper as long as it sticks to the copper board.
  3. Put the clothes iron on top of photo paper for ~1 min, then using the iron tip, applying a bit of pressure, carefully move the iron tips on the paper for 3 - 4 minutes. (you can watch some toner transferring video/documents online before DIY, like [3] [4])
  4. Removing the paper
    1. Soaking it in water can be very counter-productive, many papers come off cleanly just by pulling. what water does it that it breaks teh bond between the layers of the paper and you have to remove each layer separately. hot water(40C ~ 60C degree) is better, keep it there for ~10mins. cold water need much more time; using finger and keep the board wet when you remove the papers. DO NOT use nail, it will scratch the toner;
    2. After paper removal, you still want to clean the board, because there are some residues from whatever the "glossy" stuff is. just holding it under the water tap and rubbing it with a finger usually does the strick. a toothbrush is probably better.

Checking and repairing

We can repair some track by using a permanent marker.



  • Soft brush;
  • An etchant, I am using APS, bought here(it's 95% APS + 5% Copper(II) sulfate), the traditional etchant for copper is Ferric Chloride, someone also use the Hydrogen Peroxide;
    • AnotherHydrogen Peroxide (H2O2) with muriatic acid (HCl). advantages: works at room temperature, the etchant is a clear solution, the ingredients are very easy to find and cheap, and it's fast. disadvantage: releases small amounts of clorine gas, so you don't want anything metallic near it and good ventilation is important.
  • A etching box (a video about this etching box)for APS(no Ferric Chloride/Hydrogen Peroxide in such box) is much better, it have heater and pumper in the box;
  • Safety gloves;


For APS, the etchant:water ratio is 1:4, the etching box I am using needs as least 620g etchant and 2.5liter water, 2.5liter liquid to make the pumper works fine. after mixing up the liquid became light-blue.

The etching box has a heater and a pumper. power on the heater and pumper. put the board into etchant liquid, put something on the board coners. make sure the liquid doesn't flow the board up. after ~8 mins. when the fine tracks are clearly visible and the unwanted copper removed, take the board out and clean it in water. magical chemical!

We can use those 620g + 2.5liter etchant in ~3 month. depends on how much board etching and how you keep the liquid. when the liquid became dark blue we have to replace with a new one. after etching. get the pumper and heater out of the liquid. we better seal the box after using.


Removing toner from board

  • Acetone, the acetone will get rid of everything. if you have problems getting acetone (its sale is regulated at some places since it's also used for some processes in the production of illegal drugs), you can try paint thinner/remover/nail polish remover. pure acetone is better for your health, though.


Before do any soldering. please read this document about solder, alloys commonly used for electrical soldering are:

  • 60/40 Tin/lead (Sn/Pb)
melts at  188 °C or 370 °F
  • 63/37 Sn/Pb used principally in electrical/electronic work. the 63/37 is a eutectic alloy, which:
has the lowest melting point (183 °C or 361.4 °F) of all the tin/lead alloys; and
the melting point is truly a point — not a range.
  • Pb-free solder SAC305(Sn96.5Ag3.0Cu0.5)
SnAgCu alloy has a much higher melting temperature 217°C or  422.6°F


  • Toaster oven
  • Multimeter (with thermometer featture)
  • SMD rework station
  • Iron tips and solder
  • Solder paste(the alloy)
  • Soldering flux
  • PCB clean liquid

Components soldering

I use the oven do those components soldering. first put the solder paste to all footprints(except the BGA footprint), I cannot buy the solder paste in syringe. so I use a toothpick print the solder past on those footprint. then put those components on top of footprint. after align the bga chip. we can put them to oven. see below.

BGA chip

Setup oven + thermometer

BGA soldering by using the oven

First put a very thin solder paste(the flux) on bga footprint. align the bga chip to it's footprint. then put the board to oven, we better use the same solder(the alloy) as the bga ball. so I am using the SAC305(Sn96.5Ag3.0Cu0.5), same as xc6slx9-ftg256 balls(here is the document about solder reflow guidelines). then we can watch the components solder paste(the alloy) changed from gray to shiny. then the bga balls also reflow. below is the temperature setup with my oven:

  • Set to 100C for 3 minutes to preheat.
  • Set to 200C for 1 minute for thermal soak.
  • Set to 250C for ~1 minute for reflow.
  • Turn off oven, open door, and cool to ambient with room air
Note that these numbers are not intended to describe the actual temperatures reached by the board.

The thermometer give a higher terperature compare to the SAC305 document(because the thermometer was under the PCB). it reached 260C when sodler(alloy) start to reflow.

BGA tester

  • Website:
  • The BGA tester uses the pogo pin;
  • It needs some holes in your PCB design for mount tester or they can make a daughter board for your board;
  • Delivery time 5 ~ 7 days.
  • Price: 9 ~ 18 RMB/PIN, depends on BGA chip bitch, ball size, and your chip frequency;
  • Earnest money: 30%
  • Holes for BGA tester (TODO)


  • BGA reballing station;
  • A metal mask for you chip, there are 2 types on metal mask. direct-heat, non-direct-heat;
  • BGA solder balls;
  • Remove balls
  • Place soldering paster
  • Finish

QFP chip

I am using ~270°C for solder the chip to the pcb. before soldering I have to put this liquid flux to all pins make the solder flow easily.


  • Whatever the flux, you should clean the board afterwards. the chemicals in the flux can be quite conductive (< 100 kOhm/mm) and your circuit may act in very strange ways if there's flux on the board, particularly when still wet.



For configure, FPGA only starts to configure after all VCCO's have reached some level. all the GND/VCCAUX/VCCINT all internally connected. each set of VCCO_X pins are internally connected.


For using our JTAG-serial board. we have to connect 6 wires. the right picture shows pin layout, the connection and jtag command:
M1 JTAGserialpod Pins.JPG
Vref -- 3.3v
TMS -- P107
TCK -- P109
TDO -- P106
TDI -- P110
$ cat > t
cable milkymist
$ jtag t
Connected to libftdi driver.
IR length: 6
Chain length: 1
Device Id: 00100100000000000001000010010011 (0x24001093)
 Manufacturer: Xilinx (0x093)
 Part(0):      xc6slx9 (0x4001)
 Stepping:     3
 Filename:     /usr/local/share/urjtag/xilinx/xc6slx9/xc6slx9

Bluetooth modular


  • Convert 1xAA to 5V link
  • Convert 2xAA to 5V link
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