−Inhaltsverzeichnis
Thermometer width DS18S20
Hardware
There electronics in the car to the employment comes I to the current supply special attention dedicated. The 12V can of 7V – 15V vary with peaks to 40V positively as negative. Further no disturbances are to retroact on the car. Around this to keep different screening measures are intended. In addition an entrance protection against the voltage peaks. The display was inserted set off to control electronics and both housings inside with a EMV spray on copper basis was treated. Around this to keep different screening measures are intended. In addition an entrance protection against the voltage peaks. The LED display was inserted set off to control electronics and both housings inside with a EMV spray on copper basis was treated. The housings was put on Ground. The +5V for ATTINY, sensor and the LED display is produced by a regulator controller LM2574. So that the display in the dark does not dazzle with to switch on the light form the car the display is somewhat dimming.
Software
The software is written with WINAVR20090313. All 10msek. takes place an interrupt where a time variable is counted up. In the major loop with „switch case“ program sequence is then steered. First tries the DS18S20 to initalised and with success the measurement is started. The transformation lasts approx. 800msek. Afterwards the memory of the sensor is selected. At a negative temperature (scratchpad [1] not equal 0) another computation is used than at a positive temperature. The leading zero are still faded out and the result is sent to the LED display. Afterwards the cycle begins again. After the start of the measurement still queried whether switches light on from the car. Is the light indicates then dimmed the LED display.
For more detail: ATTINY2313 Thermometer width DS18S20
