Thermometer using DS1621 and Nokia 3310 LCD interfaced with ATmega8

Hi friends,
in my last post I had discussed Nokia 3310 LCD interfacing with AVR ATmega8. It's really fun to work with this LCD.

Now, here I'm presenting one application with the same LCD: Designing a thermometer using DS1621 temperature sensor IC. DS1621 is 8-pin sensor from Maxim, with temp range of -55 to +125 degree C, which can be interfaced with microcontroller over two-wire serial i2c bus. It has operating voltage range from 2.7 to 5.5v. I'm operating it here at 3.3v, same as the one driving the LCD and ATmega8. DS1621 doesn't require any external components to measure temperature. It has got continuous or one-shot temperature reading capability to save power.
Check out the schematic:


Here is the Proteus ISIS simulation result:



I'm using here LM317 for getting 3.3v supply, any 3.3v rgulator can be used to replace it. The LED is only for checking the health of the circuit incase nothing comes up on display. The circuit is programmed to update temperature appx. every second.

I've taken help of LFG application for generating different sizes of fonts for the LCD, thanks o the author M.Ebrahimy. The application can be downloaded from here:
LCD Font Generator

I've created library functions for DS1621 interface with AVR using ICCAVR compiler. This functions can be used with i2c base routines discussed in my earlier posts. You can download the project source code here.





Download
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HEX file
Source code (including the 3310 & DS1621 Libraries)
Proteus Simulation Model


(Do you wanna use this HEX file but don't want my name on the display?? Well, just learn how to play with hex file from intel HEX-file tutorial, find ascii characters of my name in the hex file and replace them with yours!!)

Download Datasheets:
1. DS1621
2. ATmega8

Thanks!!
---------
Contact: ccd@dharmanitech.com

NOKIA 3310 LCD interfacing with ATmega8

Hi friends,

using graphic LCD in a project gives itreally a good look and flexibility of displaying different characters and shapes. But, the graphic LCDs are quite costly.

The NOKIA 3310 LCD provides a really low-cost solution to add a small graphic display into your project and also good for learning purpose. The LCD is SPI bus compatible, saving many pins for other uses. It operates at 3.3v.

Here is a small circuit for interfacing the 3310 LCD with AVR microcontroller ATmega8. The schematic includes LCD connection with SPI port of ATmega8 with other connections required by LCD. The 3.3v is generated using adjustable voltage regulator LM317 (I was not having any 3.3v regulator at the moment). An LED is also connected with microcontroller just for making sure that the controller is working, particularly when you don't see anything on the display!

Here is the schematic and the pin details of the LCD:

The connector of LCD is 'touch' type. So, I made a small connecor PCB with tracks touching to the pins of LCD. The pcb was pasted at backside of LCD using cello tapes as shown in the back-view image
.

Here is a testing with Proteus ISIS Simulation:


The program routines are written in C with ICCAVR compiler. I've created a library for this display. The low-cost, easy availability has made me relly like this display.
I'm going to use it for

doing other stuffs, too!

Download
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3310 Library (ICCAVR)
3310 Library (AVR-GCC, winAVR, AVRStudio)
3310 project (CodeVision AVR)
Proteus Simulation Model (Simulation was done with CodeVision AVR Hex file)


Check out my thermometer project with this display:
Thermometer with Nokia3310

Download datasheets:
1. ATmega8
2. PCD8544 - nokia 3310 display controller

Thanks!!
--------
ccd@dharmanitech.com