Summary of Automatic Water Heating System 1.0
This article describes a low-cost, electricity-saving water heater controlled by a Digispark Attiny85 microcontroller. The system maintains water temperature between 44°C and 46°C using a relay and sensor, automatically turning the heater off or on as needed. It features a buzzer alarm, LED indicator, and switchable modes via a slide switch.
Parts used in Automatic Water Heating System 1.0:
- Plastic enclosure
- 12v 500ma step down transformer
- Relay board
- Digispark Attiny85
- Switches
- Buzzer
- Led
- Temperature sensor
- Mains cord
- 3pin Mains Socket
- 4.7k resistor
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.
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.
Source: Automatic Water Heating System 1.0
- How does the system control water temperature?
The microcontroller turns the heater OFF at 46 degrees and restarts it if the temperature drops. - Can I change the temperature mode?
Yes, a slide switch is used to change the temperature mode. - What happens when the target temperature is reached?
The heater turns off and the buzzer beeps. - Which microcontroller is used for this project?
A Digispark Attiny85 is used to control the temperature. - Why must the same wire gauge be used for the relay?
The relay draws more power, requiring the same wire gauge as the heater's wire. - How is the temperature sensor connected to the Digispark?
A 4.7k resistor is soldered between p0 and +5v pin in the Digispark board. - Does the device save electricity?
Yes, the article states that this poor man's geyser saves electricity. - Is there an audio alert in the system?
Yes, a buzzer is included to beep when the temperature reaches the set limit.
