Introduction: DIY PCB Fabrication
I was impressed by bjkayani's instructable Beeduino ,the tutorial is well detailed and also Thomas Fischl's USBASP.I decided to make both these circuits on one board.Not by soldering a perfboard or on breadboard but on our very own built PCB!! Yes we can make it at home!! I will show two ways of etching PCBs and also tell which one would be better. Enjoy!!
Step 1: How It Works??
- The atmega 8 converts the usb to serial,part of usbasp.
- Usbasp can be of two types 6-pin or 10-pin nothing different!
- Here an external simple MCU circuit has been made.
- Most arduinos operate at 5v of usb but using a voltage regulator i.e 7805 we regulate any voltage upto 12 volts.
- We had used 16 Mhz crystal oscillator,internally the IC contains 8 Mhz clock but needs external one for faster processing.
- The push-button changes from 5V to 0V (or vice-versa) only when it is being pressed down, which is for a few milliseconds usually.
This is a little introduction of what we are making.
Step 2: Things We Need
For PCB etching :-
- Ferric chloride/HCl and hydrogen peroxide (Ferric chloride from school lab and HCl from hardware store,Hydrogen peroxide from medicine store)
- Single-sided copper clad board
- Photo laser sheets
- Electric Iron
- Laser Printer
- Rotary tool with needle like usually 0.8 mm drill bit
- Plastic container
- Safety for eyes
General tools :-
- Soldering iron
- USB cable from B-type to Ordinary
Step 3: Printing Circuit
Here are some eagle and express pcb files.Print them on Glossy paper side and cut out the printed portion.The MCU circuit itself was desined by bjkayani.I used the same.Here is the cirucit of USBASP as well as MCU. Here is a video complete video of pcb etching tutorial by Make.
Step 4: Sanding
Using scrubber or sand paper rub the whole copper clad board to remove any oxidization or stains.
Step 5: Printing
Set the iron to maximum heat and then place the sheet on glossy paper and iron the sheet smoothly for about 15 minutes,then you will get proper print.In the picture this one is failed print,if this happens scrub it again using scrubber or sand paper.Try again!!Cut off the extra copper clad board.If you are using ferric chloride as etchant then no need to retry the toner transferring,shade the left lines using permanent marker.
Step 6: Safety!!
Safety is must while doing etching HCl and ferric chloride both can stain anything that comes in its way and also choose a well ventilated place for etching the PCB.
Step 7: For HCl
If you choose HCl and hydrogen peroxide then it would be safe to apply a coating over the print like that of marker or polish.Dip it into 50-50 solution of hydrogen peroxide and HCl the solution would turn green the green salt is copper chloride which can be used again for etching PCb by dissolving it in HCl !! It would take about 1 hour if you are using HCl with 30% concentration.
Step 8: Ferric Chloride
Ferric chloride is better choice because it etches faster and more perfectly than the previous method.Take about 40 grams of ferric chloride and dissolve it in about 100 ml water.The solution must appear brown without board and when we dip it appears somewhat yellowish in color.Not a chemical reaction only reflection of copper!! Dip in it for about 15-20 minutes till the full PCB etches!!
Step 9: Congratulations!!
Take out the copper clad board from the solution and then wash it under water and pour some acetone on board removing the toner,you would see a beautifully etched PCB.
Step 10: Drilling
Use a needle like drill bit between 0.8 mm to 1.2 mm and you would require 3 mm drill for drilling the holes for dc jack and dc ports as well as voltage regulator.Drill carefully a small mistake can break lines of your hand-crafted PCB.
Step 11: Start Soldering
Switch on your soldering iron and solder all the components as directed in schematics and PCB layouts.First of all solder resistors and then other components.
Step 12: Soldering Tips
Don't apply too much solder all little quantity enough to make the pin and line in contact would be enough!!
Step 13: Soldering Other Components
Bend the voltage regulator IC and also check the stability of every component.Check again if any component is left to be soldered.
Step 14: Done Soldering!!
Cut off extra pins of components and insert the ICs now and it is the time to test our device!!
Step 15: Checking
It is always a good idea to check everything before powering it on. I would suggest checking the continuity of each trace using a multimeter.
Step 16: Done!!
Thanks for seeing my instructable!! This is a very cheap and homemade solution for those costly arduinos. I have 2-3 Arduino but I love this one as it has been made by me! I hope you like it!! You can ask if you have any questions!!
Please vote if you like this!!