Internet of thing Digital Thermometer DS18B20

I purchased this ic a long time ago. Never had any chance of using it. But now the this small itsy bitsy integrated circuit is sending data on the internet.

You can check the link at

It is connected on a custom gateway device.

The ds18b20 can take power in two ways. The circuit that i made is using the parasite power.

This time i used clear nail pail paint over the copper trace.

ds182b20 interface schematic
ds182b20 interface schematic

printed circuit board is designed in KiCad open source EDA tool.


UPDATE : 14 September 2018

Using nail paint as a substitute for PCB lacquer is a cheap solution. It should be avoided when making a rugged PCB. If their is a lot a mechanical vibrations and stress, then the nail paint will chip away leading to oxidation.

5V voltage regulator using 7805 | Complete Process

While making circuit a power source is the essential component. Power source can be made by different circuit. Here i used the most popular integrated circuit 7805. Which is a 5v voltage regulator.


I made this schematic in KiCAD software.

PCB layout in Kicad pcbnew
3d rendering of pcb
3d rendering of pcb

After this i made some print out. Drilled a few holes. As i do not have a laser printer i am unable to make a photoresist mask. So i use old school permanent marker for masking wire trace.

7805 PCB in ferric chloride solution
7805 PCB in ferric chloride solution
7805 pcb final output
7805 pcb final output
Component Placement on board
Component Placement on board
Solder Component
Solder Component

It is not the best job of solder that i have done. But it is not worst i did and definitely not the best.

Nail Paint as Solder Mask
Nail Paint as Solder Mask

I did not have paint or the PCB lacquer. But in my home i found this used nail paint. It barely works.

Testing of PCB
Testing of PCB

Final output.


PCB Fabrication

Well after you have built your circuit. You need to realize that circuit to test or deploy. 

Single Layer Non-Commercial PCB Fabrication Process Sequence

  • Make Your Schematic in any EDA tool like KiCad, Eagle, Express PCB, Proteous.
    Note: These EDA tools are not inter compatible with each other so make sure to use the appropriate tools
  • Make the PCB Layout using EDA tools.
  • Now there are two type of output
    1. Graphic output (PDF, JPEG, BMP, SVG)
    2. CNC text output file or Gerber files
  • After you made you PCB layout. The base file consist of copper layer and silk layer.
    Copper Layer: This where all your traces (connecting wires) reside.
    Silk layer: This layer consist of the graphic layout. It for the accessibility of the user for easy insertion and Post production annotations. You can avoid this if want.
  • Two methods of etching
    1. Tonner transfer : In this method the plastic tonner of the laser printer is transfered to the PCB by the application of heat. 
    Heat can be applied by using the Laminator or the cloth iron.

    2. Photoresist method : This is an old method. It produce neat result but it takes a lot of step for understanding. 
    Three steps of photo resist development.
    a. Apply photoresist film
    b. Apply Mask
    c. expose the film under UV light : This can be done by placing the copper clad board into bright sunlight for a brief period of about 10 minute(try a test pcb for the correct exposure time) or you can place the board under a UV LAMP
    d. develop the photoresit by submerging the board into a solution of a sodium carbonate (1 gm of sodium carbonate into 500ml of water)
    e. etch the board by submerging the board into any one of the following solution.
     1. ferric chloride (dissolve ferric chloride into 200ml-300ml water till it becomes saturated)
    2. Muriactic Acid Solution (muriatic acid solution)
        (Old name for HCL)
    3. Copper sulfate + sulfuric acid
    4. Nitric Acid
    5. Hydrochloric acid + hydrogen peroxide
    f. rinse the board in water.
    g. photoresist removal : submerge in sodium hydroxide solution
    h. rinse the board in water.