Summary of Temperature Indicator Using attiny2313 micrcontroller
This article describes a temperature monitoring and control circuit using a DS1621 sensor and an ATtiny2313 microcontroller. It measures temperatures from -55°C to +125°C, features three LEDs for range indication, and includes user-definable high/low thermostat settings. The system controls a relay to switch heaters or fans based on thermal conditions, powered by 4.5–5.5V DC.
Parts used in the Temperature Indicator Project:
- DS1621 temperature sensor
- ATMEL 90S2313 (ATtiny2313) microcontroller
- Three LED's
- One relay
- BC557 PNP transistor
- Resistors
- Printed circuit board
Description
Features:
- Measures temperatures from -55°C to +125°C
- Three LED’s to indicate in what range the temparature is.
- User definable thermostat with high and low settings
- Output via a relay to control a heater element or a blower fan (or something else)
- Power supply ………………….4.5 to 5.5 VDC
- Power consumption ………..15mA
This circuit uses a Dallas DS1621 temperature sensor which indicates the temparature of the device. The temperature sensor has an termal alarm output, which becomes high when the temperature of the device exceeds a user defined value. When the temperature drops below a user defined value, the alarm output becomes low. In this way any amonut of hysteresis can be programmed. The values are stored in a special register of the device that is nonvolatile. The signal of the alarm output is amplified by a BC557 PNP transistor, that drives a relay that can switch a heater element or a blower on or off. The temperature settings and readings are communicated to/from the device over a simple 2-wire serial interface. An ATMEL 90S2313 microcontroller controls the serial communication to/from the DS1621.The microcontroller also controls three LED, only one of the LED’s is on when the temparature is within a certain range. The range of the temperature in which the LED’s are on can be set by the user in the program code. The circuit needs to be powered by a 5V power supply, which can be obtained from a wall-wart.
Hardware
It contains only a few parts, a DS1621 temperature sensor, a attiny2313 micrcontroller,three LED‘s one relay and some resitors. I have made a little printed circuit board for it.
Software
The software for this projects is made with the AVR Bascom compiler.
For more details, click: Temperature Indicator Using attiny2313 micrcontroller
- What is the temperature measurement range of this circuit?
The circuit measures temperatures from -55°C to +125°C. - How does the device indicate the current temperature range?
It uses three LED's where only one LED is on depending on the temperature range. - Can the thermostat settings be changed by the user?
Yes, the user can define high and low thermostat settings which are stored in a nonvolatile register. - What component drives the relay to control external devices?
A BC557 PNP transistor amplifies the alarm signal to drive the relay. - Does the system use a serial interface for communication?
Yes, it communicates with the device over a simple 2-wire serial interface. - What power supply voltage is required for this project?
The circuit needs a 5V power supply, specifically between 4.5 to 5.5 VDC. - Which compiler was used to create the software for this project?
The software was made with the AVR Bascom compiler. - How does the thermal alarm output behave when temperature drops?
The alarm output becomes low when the temperature drops below the user-defined value.
