Turn-key PCB assembly services in prototype quantities or low-volume to mid-volume production runs

Dual digital thermometer with I2C interface

Stand alone digital thermometer is very easy to build – especially when microcontroller has an ADC interface built in. Tuxgraphics has posted a new cute thermometer project which uses two NTC temperature sensors. They are cheap and quite precise for most hobby projects. One problem that they are non linear. But this what microcontroller is for. Some basic semiconductor physics and math and characteristics is straighten. Device reads temperatures from two sensors – inside and outside. Both temperatures a displayed on standard HD44780 compatible display and additionally information is sent to PC via I2C interface. Why I2C and not UART? It helps to save the hardware like MAX232 and multiple capacitors. Having connectivity with PC is great – you can always call a small GUI to see current temperatures or by running cronjob you can collect a long term statistics or even publish on the web. Continue reading

Digital thermometer with large 7 segment LED display

Thermometer is based on PIC16F628 microcontroller which reads temperature data from DS1820 sensor. All three 7 segment indicators are connected to TPIC6B595 shift register. Registers are able to drain current for LED indicators that are powered from 12V voltage. Temperature sensor is capable to rank values from 0 to 99.5ºC with 0.5ºC accuracy. No negative values (hopefully temperature value won’t drop below zero). Program code is written for CCS C compiler. Great source to learn how to read data through 1-wire and drive powerful 7 segment LED displays. Continue reading

Dual Thermometer with serial output

Building digital thermometers is probably one of the common tasks around embedded hobbyists. However more such projects more choices so more things that can be learned. So this one uses PIC16F876 microcontroller with MCP1047A temperature sensors connected to it. Thermometer displays two temperature values – inside and outside. The hardware of this thermometer is pretty simple – PIC reads temperature sensors via ADC. Temperature values are displayed on standard 2×16 LCD and logged to RS232 at desired intervals. ASM code is available. Continue reading

A weather station with a build-in web server

Embedded web applications are always exiting. Once device is connected to internet, you can have access and control from anywhere including cell phone.   Weather station is a modular structure which consist of AVR based web server and sensor board. There are two LM335 temperature sensors and Freescale MPX4115A absolute pressure sensor attached. There is also a wind measurement sensor planned. Here you’ll find the latest project files. Continue reading