Hi,

I'm building a weather station and I would like to imrpove my electric consumption.

>>Configuration: Arduino UNO SMD rev2 + Shield SD Sparkfun + SHT15 (Temp & Hygro )+ MLP115A1 (pressure) + 9V battery

In summary, I need to manage one measurment per minute. I would like to sleep the board during 55mn and wake up 5mn before a measurment, just to heat correctly the sensors. I know that, there are 6 kind of sleep modes, but, I refused to use an external counter.

I'm a recent user of Arduino and I need a lesson about this using...

I don't know exactly what sleep's level I can hope with a internal counter. I thought use the watchdog, I'm currently trying to understand how use it...
In a second time, I thought during my 5mn of heating make a choice to shutdown some board's compoments with this kind of command:   power_timer0_disable();
  power_timer1_disable();
  power_timer2_disable();
  power_twi_disable();
  ...
but I don't know if it's available...

Is there someone to teach me???

Of course, without sensors, the arduino board and the SD-shield offer exactly 3,3V!!!
When I reconnect my captors on the pin 3,3V, the voltage rise to 4,3V.
I remember previous Mr Gammon's replie, I've probably a parasitic power which is derived from the data lines... But, is it dangerous? With the 5V source, the running looks completely normal...

I've a another problem now.
I made a test during this weekend. I ordered a measurement per minute and the 9V battery worked only during 5 hours!!! I'm going to use the shutdown on the MLP115A1, after each measurement, the SHT15 is switch on sleeping mode. Finally I would like to reduce the consumption from the Arduino board. Do you know how can I do?

For me I'm really far from this treshold...

From the different datasheets, the consumption of the both captors is really weak: MPL115A1(10µA Max) & SHT15(25µA Max).
About the SD-shield Sparkfun, I don't know.
For me the current level is not the problem, at the beginning I used the project directly on the USB plug. Now, I'm using a new 9V battery, just to avoid a degradation on my computer...

Currently, my project is running correctly, but I need to use the 5V.

Hello,

thanks so much Nick.

I completly agree with you, and i stoped really quickly to run without vcc yesterday.
I need to use your advices for my scketch but I think having found the gulty...

With Vcc=5V all captors run correctly. At the beginning I decided to use the better voltage for the MLP115A1 and the SHT15. 3,3V was the better level to reduce the consuption. But now, when I control the voltage, I find 4,3V!!! and it's also the same voltage on the SD-shield and the Arduino Board. I know that 3,3V is using by the SD-card, and in fact I have some regularly problems to establish the communication with the card...

In brief, in think the regulator 3,3V on the Arduino board is defective... that can explain all events...

What do you think about my supposition? I have also some doubts about the SD-shield...

Have a good weekend.

Hello,

Thanks for your advices.
I used it, but the MPL115A1 didn't work. I was frustrated, and I decided (I don't know why) to play with the chip select from the serial monitor. When I withdraw the connection from the D4 (CS MPL115A) the measurement changed. The values were not correct, but different. Also, I decided to withdraw the VCC pin (3,3V) just to know if the sensor was shutdown or enable...

It's just unbelievable, it's running perfectly now!!! without vcc!!! ??? I don't know why...

I'm going to read again and precisely the datasheets...

I added some pix in the attachment.

I'm wondering if my alunimun support is not the reason of this malfunction? perhaps that create an electric connection between the different boards... I'll inform you about my research...

Thanks so much.

Hello,

I'm a recent Arduino's user. I'm French, and perhaps not a English master...
I'm trying to build a weather station.

I'm using a UNO-smd-R2 with a Sparkfun SD-shield and a barometric pressure captor MPL115A1.
The both compoments use the SPI. They are running perfectly, but when try to gather the both, SD-shield and MPL115A1, this last one is inactive, sending false values.

My outline is this following:

Code:

          D13  D12  D11  D10  D9  D8    D7   D6   D5    D4   D3   D2
MPL115A1   SCK  SDO  SDI  ___  SDN  ___  ___  ___  ___  CS_  ___  ___
SD-Shield  CLK  MISO MOSI___  ___  CS    ___  ___  ___  ___  ___  ___

>>I decided to avoid the pin 10 which is the internal ChipSelect from de ArduinoBoard. I don't know if it's a good choice or good understanding? I understood the ArduinoBoard must stay the master shield...
>>In my scketch, I delcared the chipselects PINs, D4 and D8 in Output for the initialization : digitalWrite(CS_PIN, output);. When I want to control and read the MPL115A1, I switch the SD-shield chipselect on a High level : digitalWrite(CS_PIN, high)

I had the scketch in the attachment, if someone can help me to understand, find the good way or my mistakes, I will be so grateful.

And sorry again if my English translation is not so well...

Moderator edit: [code] ... [/code] tags added. (Nick Gammon)