This project is a digital thermometer that uses a microcontroller with analog-to-digital capability, an analog temperature sensor, and some seven-segment displays. The circuit is pretty simple and it can be powered by a 9-volt battery which makes it very portable.
Please continue to read as I go a bit deeper to the details of what builds this easy project.
The Microcontroller
This project features ATtiny26L microcontroller. This microcontroller is from the AVR family of microcontrollers manufactured by Atmel. It has 2Kbytes of flash memory and 128 bytes of SRAM which is enough for this project. It also has several 10-bit ADC channels, more than enough for the analog temperature sensor, and it has enough digital I/O pins for the seven-segment displays.
The Temperature Display
To display the temperature, I used four common anode seven-segment displays. The seven-segment displays are driven by PNP transistors and a special technique called “multiplexing” is used to effectively control the displays using only a few digital I/O pins.
Notice how I mounted the fourth seven-segment display by reversing it to display the °C sign.
The Sensor
The sensor used in this project is LM35. LM35 is an analog temperature sensor and it has a sensitivity of + 10.0 mV/°C. It is accurate enough and it is suitable for different applications. It is rated for full -55° to +150°C range.
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Reversing the 7-segment is a good idea.
I think there is an IC that converts an analog signal into 7-segment data directly but I don’t remember its number, but I think it would be cheaper than a microcontroller
^^^
There is. It is ICL7107CPL
However, it costs 12 dollars compared to ATtiny26L which is just 2 dollars.
Hi, what component did you use for IC1?
Regards
Tom