- MultiTherm Development
- MultiTherm Operation
- MultiTherm Logging and Demo Board
The logging mode is entered by pressing any button other than MODE while on the startup screen. Along the left-hand side of the screen are either one or two device numbers and temperature readings in °C. These readings are the result of the previous temperature scan. The time of the last scan is displayed in the upper right, and the time until the next reading is displayed in the lower right. While in logging mode, the UP and DOWN keys page through the available sensor data. The data is displayed in the order determined from the device ordering screen.
Each time the countdown reaches zero, another reading of every thermometer on the 1-Wire bus is performed. In addition to displaying these latest reading data on the LCD, a record of each reading is transmitted out the built-in serial port. Serial communication occurs at 19200 baud, 8 data bits, no parity, and 1 stop bit. An example of the out put is shown to the left. Following the header section are a series of temperature records. Each temperature record consist of a time-stamp of when the data was taken, followed buy a series of semicolon (;) separated temperature values. The values are ordered from left to right in the same order established on the device ordering screen.
You can use almost any terminal program, such as Window’s Hyperterminal or the popular freeware package Br@y++ Terminal, to view and save the serial output. In the Sources section below, I’ve included a sample Java program to demonstrate how to parse and graph the temperature data from a saved file.
Below are photos of a sample demonstration board constructed to test the finished design. The board artwork and schematic in the sources section are designed for easy fabrication by hobbyist board techniques. The double-sided board in the photos was actually constructed using the toner-transfer technique. A mixture of through-hole and SMD components was used to reduce the number of vias and holes required.
Disclaimer and License
It worked for me so it should work for you, but no guarantees. Feel free to use the schematics and source code on this page as you see fit, but a little attribution would be appreciated.
- Logger Source Code v1.113 – AvrGCC/Studio 4 (639K .zip)
- Cadsoft Eagle Files (rev. B) (93K .zip)
Schematic – (50K .pdf)
Top (29K .pdf)
Bottom (21K .pdf)
Component Layout (34K .pdf)
- Parts list and build notes (5K .txt)
- PC graphing example – Java Source & Executable (843K .zip)
Everything above! (2M .zip)