Amazing Home automation system with STM32F103 microcontroller Part 1

Amazing Home automation system with STM32F103 microcontroller

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This is ongoing project of building Home automation system ( smart home system ), which will for the start have measurement of temperature and humidity.

It will consist of number of parts ( number of blog posts ).

It is planed to work with micro controller STM32F103C8T6

 and 3.5" TFT LCD.

Next step will be to control relays for ceiling fan, etc.

Next will be to add ESP8266 to have connection to the internet, so the system can be controlled remotely.

Till now I have managed to make a printed circuit board.

Home automation board bottom

Home automation board top

Not really nice to look at, but it is working, and working from the first attempt :-)

The PCB is designed in EasyEDA, and made with toner transfer method 

Except headers for STM32 and TFT LCD, I have also added 3.3V and 5.0V linear regulators.

Beside this, there is also part with MC34063 as a buck converter, which is in front of small linear regulators.

This part is made with intention to connect this device to external power source of 12V.

Of course, everything is programmed using Arduino IDE and STM32duino board.

For measuring temperature and humidity we use DHT11 sensor, which measures temperature and also humidity and uses just three wires, plus, ground and signal.

 

DIY method of making PCB using toner transfer method

 

This is a DIY method of making PCB using toner transfer method. 

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The most important thing is to have good print , done with good quality toner. 
Here we use some dangerous chemicals so be very careful if you going to do this at home.
Please check following video for details, and I will show you also few steps in following points.

As a first step we use sandpaper to remove any oxidation from copper plate, than clean it with paper tissue.

Than we use contact cleaner or acetone to clean any grease.

Then we secure the paper with printed circuit with adhesive tape.

Then  we use nail polish remover ( or acetone - nail polish remover is actually acetone ), take small amount and spread it evenly on the surface of the copper plate.

Ten minutes after we can start to remove paper very slowly.

After we removed first layer of paper we put board into the water, and slowly rubbing we remove the rest of the paper.

This rubbing should be done VERY carefully, so we do not damage toner traces.

And in the end , the result is very satisfactory.

Next step will be to do the etching, which could be done with HCL and hydrogen peroxide.

Etching PCB with HCL and hydrogen peroxide

This is a DIY method of making PCB using HCL  and hydrogen peroxide .

Visit my Youtube channnels :  Electro_Magic ; Practical Tips  ; Delphi practical school             

The most important thing is to have good print , done with good quality toner. 
 Here we use some dangerous chemicals so be very careful if you going to do this at home.
Please check following video for details, and I will show you also few steps in following points.

First you must have good print, done with good quality toner.

      Then we put prepared PCB in plastic box.

For etching we use HCL and Hydrogen peroxide.We pour in HCL just enough to cover PCB, then we add a little of peroxide.

We immediately see how reactions with copper occur.

Here we see bubbles in the reaction of acid with copper.

After few minutes we can see full reaction .

After etching is done, we rinse pcb with water.

Use a steel sponge to remove any toner residue.

The PCB looks almost perfect.

It is very important to have a well-done print at the very beginning, with quality toner.

LAB power supply with current control (Tip for 10 )

LAB power supply with current control from 0 to 1.5 Ampere (Tip for 10 )

This is simpler version of variable power supply shown in this post.

Voltage is variable from 0 to 30 Volts and current from 0 to 1.5 Ampere.

LM317T is mostly in standard setup.

Potentiometer for voltage control is connected to ADJ pin of LM317T and negative voltage via trim pot, with which you can adjust minimum voltage.

Current control is done using  LM393 comparator and shunt resistror.

Output of LM393 is connected to ADJ pin of LM317T and regulates amperage, sensed over shunt resistor.

LM317 Variable power supply with current control (Tip for 10 )

In this post I will show you easy to construct variable power supply using LM317 with some other components.

Final result is usable variable lab power supply with current control.

Current control is done using  LM393 comparator and shunt resistror.

Since I used one panel meter for voltage and current reading , I added LM358 OP amp to read current used by attached loads.

LM358 amplifies voltage detected on shunt resistor and amplify it to appropriate value which is set by variable trim pot.