The brain of this project is an AT90S2313 that controls the LED Display thus showing the temperature read from a DS182 temperature sensor. The temperature sensor chip, DS1820 is connected to PD1 with a 4.7k pull-up resistor. The circuit presented here uses only one sensor, but you may tie multiple sensors on the same line and modify the program to read it with the help of internal chip ID.
ATtiny2313 Thermometer: [Link]
There are plenty of digital thermometer schematics out-there but as i said in an earlier post, its nice to have where to chose from. Being based on a tutorial about Analog to Digital conversion, it is very easy to understand the functioning of the device, and you can build it with any micro controller even if it doesn’t have a builtin ADC.
The temperature sensor used in this project is thermistor which is very suitable for measuring ambient atmospheric temperatures, but you could replace it with any other type of temperature sensor, that would function in a range that is more adequate to your application.
Digital Thermometer: [Link] – [Via]
The following project its a basic thermometer that can measure data from 2 sensors, for example you place one sensor inside the house and another one outside. The schematic is plain simple DS1621 or DS1631 digital temperature sensor and a bunch of resistors and diodes. You can use smd parts or trough-hole, it doesn’t really matter but if you want to keep things small and cool, i suggest you use smd. Also on the pcb you will solder a DB9 connector so you can stick the small pcb directly into your COM port. The measurement is than showed on the windows taskbar.
DS1621 pc thermometer: [Link]
As shown in the schematic, temperature sensor of our electronic thermometer is LM35DZ. There are some kinds of LM35 IC, since it is cheap and easy to find we used LM35DZ in our project. It measures from 0°C to 100°C with a very linear output graph.For one degree change, it increases its output 10mV. On the Electronic Thermometer Schematic other hand, this circuit measures temperature values only between +10°C and +39°C. [Via]
To get full info and schematics follow the link to authors page
I found this project on Kifo’s electronic website and I consider it very accessible to beginners. Although it’s really easy to build, it can be impressive to you and to your friends. Nokia 3310 has a LCD with 84*84 dots, that isn’t that hard to get and can be very useful in DIY (do it yourself) electronics. The LCD supports two modes of operation (normal and inverse); the jumper placed on the back of the device is used for changing modes.Negative temperatures are given a “minus”, the bar shows temperatures normally but with an added minus.
The first thing you need to do is to get yourself a Nokia 3310 and start extracting the LCD. You should be very careful and patient during this process, because as you know the display is just a thin piece of glass that is very sensitive. There is an 8 pin connector on the back of the display, in our case it’s glued to the glass (Nokia 3210 has “rubber” connectors so this one is much easier to use). This is a Phillips PCD8544 display, it can be easily found on the net if you want more information about it.
The next step is making the board which is small and easy to build. You should place some plastic edges on the board so the display rests on them and not on the solder points.
Next step is to assemble the board, and it should look like in this picture. Notice the sensor is in a socket, it is also possible to connect it at distance by wire.For more detailed instructions and downloads of needed files go to Kifo electronic.
Here is a list of technical characteristics:
- Voltage ………………….. 3 – 3.3 V
- Range………………..-55 to 125 C
- Min. temp. step ………… 0,1 ‘ C
- Max. error ………………. +/- 0,5 ‘ C
- Max. resolution …………. 0,0625 ‘ C
- Temp. refreshed every…. 1,2 sec.
- Dimensions ………………. 40 * 38 mm
- 2 modes of display ………normal/inverse
- LCD………………………. 84*48pixela
- Amperage…………….. 0,2 mA – 0,8 mA