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Posts Tagged ‘temperature-meter’

8 channel LCD Temperature meter RS232 – AT90S2313

This is the fully featured, jammed packed temperature readout unit. I can measure temperature from up at 8 DS1820 digital temperature sensors all on the same 1-wire bus. That’s right only 3 wires are needed to go to all the temperature sensors, GND, VCC and 1-wire data. All sensors will connect to the same cable! Anyone who has used the DS1820′s will know that each DS1820 sensor will have a 48bit serial number that is used to address the sensors. With this unit the microcontroller will search the bus automatically for all present DS1820′s and record thier serial numbers in memory. You just connect the sensors and go. You dont have to program in serial numbers of each device.
And to add to the all the features, this unit can display two temperatures on the screen and display 8 temperatures on it’s RS232 serial port. There are a few catches. 1 – You can’t yet pick the two sensors you wish to display on the screen. I only use the unit to display inside and outside temperature so there is no insentive for me to this as an option. The first two serial numbers found on the bus are displayed on the unit. The second catch, you need a PC or terminal monitoring the serial port to display greater that 2 temperatures. No time nor date is displayed on the serial port. This can be very easily added if required. A standard terminal program can be used for logging the temperature from the Readout Unit. The comm settings are 9600bps, 8 data bits, No parity with no handshaking. The RS232 frame shows the serial numbers of all devices connected to the display unit. More than eight DS1820′s can be connected, however only the first 8 devices found are shown. After the serial numbers are dump, the temperature of these devices are then dumped to the terminal in real values. This way no conversion is required on the PC side making life easy! Below is a screen dump of 7 frames from my Readout Unit. Specifications High 0.02deg C Resolution Readouts Up to 8 sensors can be connected on the one bus with automatic search of ROM codes Displays up to 2 temperatures on the LCD panel Backlit LCD with on/off control RS232 Port for logging all 8 sensors on a PC DS1302… http://www.embedtronics.com/avr/tempavr.html

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Temperature monitor

This temperature monitor circuit is used where a continous analog display of temperature value being monitored is not necessary. A simple indication whether the temperature value exceeded a maximum level or went below the minimum level is sometimes enough. The circuit here does just that, it indicated the temperature level about +25oC (77oF) or below +20oC (68oF) by lighting one of the two LEDs.
The temperature sensor is an NTC resistor coupled to two comparators. When D3 lights, the temperature is above +25oC and when D2 lights, the temperature is below +20oC.
Temperature monitor calibration
Place the NTC resistor in cold water. Slowly heat the water until the desired maximum temperature level is reached, then adjust P1 until D2 lights up.
To set the minimum level, stop heating the water then slowly add cold water to it until the desired lower temperature level is reached as indicated by the thermomter. This time adjust P2 until D1 lights up.
The Author Name: P. Marian
Source:http://electroschematics.com/6205/temperature-monitor/
This is good site thank you.

Scriptable Thermometer

You can build a variety of simple machines with the same hardware and a different script : a charting thermometer, a vending machine that dials your number when empty, a leavening cell… thermometer with 1°F (0.5C) resolution four switch inputs, four relay outputs only an handful of cheap parts graphic LCD display

Read more original source:

http://www.geocities.com/CapeCanaveral

/Launchpad/3632/scriptherm/scriptherm.htm