low power door sensor

Olov wrote: Hi,
i have created the low power arduino according to your tutorial, but now i cant get any printouts
using debug mode or Serial.print(), and it doesnot register at the GW so something is wrong. Does the changed clock change the baudrate and if so to what? Sorry for all the questions but i´m fairly new at this programming business. I have some unmodifed pro mini and they work fine.
Regards Olov

You must compile and upload program under EasyIoT Sensor328p (1Mhz 1.8V) board. The speed of serial port will stay the same as defined in program. But you should not use speed above 9600 because they do not work correctly.

Olov wrote: Thanks for the quick answer, i got the printouts to work now. But not the tempsensor.
The onewire library uses "delaymicroseconds" is this timing compromised when running at 1 Mhz (since 1Mhz = 1us)??
/Olov

Which temp sensor are you using? DHT22? Standard DHT22 library will not work at 1Mhz, because is not optimized. I wrote my own lib and it works at 1MZh, but DHT is not suitable for low power sensor. There are better sensors for low power.

Olov wrote: Hi,
Im using Maxim DS18B20 and the OneWire library
/O

I have no experience with DS18B20 and Arduino at 1Mhz.
You lower Arduno frequency to lower operating voltage (not the power consumption). At 1MHZ it can easily operate at 1.8V. Minimum operating voltage for DS18B20 is 3V. Be careful when powering on battery. In my experience more suitable sensor is HTU21D which can operate down to 1.8V. I'm using 2 AA alkaline batteries without step up regulator and this sensor can easily operate couple of years without need to change batteries.