electronic device

mik3

Joined Feb 4, 2008
4,843
A microcontroller with a relay(s) is the cheapest solution. A means of a graphical user interface (LCD display) which will show when the next activation is going to happen would be a good improvement.
 

mik3

Joined Feb 4, 2008
4,843
First, you need to use a step down regulator from 240V AC to 5V DC to power the microcontroller and the LCD.

Then you need to learn how to program the micro.

Finally, you need to find a 5V relay (coil) which can handle a load of 240V AC and at the desired current. The relay will be controlled by the micro with a transistor.

You can consider solid state relays too.
 

Externet

Joined Nov 29, 2005
2,198
...Yes, these are what i want to build.
How can I build or understand how to build these electronic devices ?
You can build them the same way the ones in the market are. To understand how to; need to study electronics.
Mik3 is explaining how; or; buy one labeled "made in China" and dismantle to find out how you can copy it. The chinese copied it from someone anyway...:rolleyes:
 

Wendy

Joined Mar 24, 2008
23,408
The step down voltage is a requirement. Solid state electronics (which this will have to be for LCD or digital) operates in the range of 5VDC to 12VDC. Most LCD models you buy off the shelf get around it with a battery, but a relay is a power hog, and needs to be powered by the line voltage, not an easy thing to do. A battery by itself simply won't power these units very long.

Many cases it is more practical to buy than to DIY. This is one of them.

If you just want to learn how they work this can be done without actually building them. Start simple and work your way up. Something like this is an advanced intermediate learners project, it is nothing more than a glorified alarm clock. So work your way up to understanding an alarm clock (starting with the clock) and you are there.
 
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