Introduction: Automatic Water Heating System 1.0
This is a poor man's geyser. It also saves electricity. The temperature is controlled by a microcontroller i.e., Digispark Attiny85.
Please do watch my 2nd version
https://www.instructables.com/id/Temperature-Controlled-Water-Heater-20/
Step 1: Parts Needed
- Plastic enclosure
- 12v 500ma step down transformer
- Relay board
- Digispark Attiny85
- Switches
- Buzzer
- Led
- Temperature sensor
- Mains cord
- 3pin Mains Socket
- 4.7k resistor
Step 2: Cutting the Enclosure
Cut and fit the switches and socket as shown in the pictures.
Step 3: Code
I took onewire temperature example and modified so that the heater turns OFF at 46 degrees and 44 degrees centigrade and beeps. Slide switch is used to change the temperature mode. It starts again if temperature drops.
Attachments
Step 4: Assembly and Wiring
- Upload the sketch to the digispark.
- Solder 4.7k resistor between p0 and +5v pin in the digispark board.
- Now assemble and wire according to the pictures.
Note: Use same wire guage for the relay as heater's wire because it draws more power.

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8 Comments
4 years ago
Hi! i just saw your vid. and i'd like to ask what is the rated volts of the water heater? is if it 220V or 5V.
coz im interested to do this as project.
i would be glad for your response.
THANKS!
Reply 4 years ago
It is 220v 1500w
4 years ago
i need the code for arduino nano 328p pls
Reply 4 years ago
Watch my 2nd version...
https://www.instructables.com/id/Temperature-Controlled-Water-Heater-20/
4 years ago
but ......when the temperature drops again ,,,,will it turn the relay on ?
Reply 4 years ago
Yes...
6 years ago
Thanks for the instructable, I intend to use a lot of what you've done. Incase you haven't already thought about it, you should beware of legionaire's bacteria growing the water at temperatures up to 48 degrees. You'd need to periodically get the water to 60-odd degrees to kill off the bacteria that have already grown.
6 years ago
Thanks for the instructable, I intend to use a lot of what you've done. Incase you haven't already thought about it, you should beware of legionaire's bacteria growing the water at temperatures up to 48 degrees. You'd need to periodically get the water to 60-odd degrees to kill off the bacteria that have already grown.