# Low power/sleep mode with wake up on Sms

**URL:** <https://forum.sierrawireless.com/t/low-power-sleep-mode-with-wake-up-on-sms/7732>\
**Category:** Legacy AirPrime modules\
**Created:** [February 3, 2015, 1:03am UTC](https://forum.sierrawireless.com/t/low-power-sleep-mode-with-wake-up-on-sms/7732 "2015-02-03T01:03:33Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![ankitparikh](https://avatars.discourse-cdn.com/v4/letter/a/a6a055/32.png) [@ankitparikh](https://forum.sierrawireless.com/u/ankitparikh)\
**Post date:** [February 3, 2015, 1:03am UTC](https://forum.sierrawireless.com/t/low-power-sleep-mode-with-wake-up-on-sms/7732/1 "2015-02-03T01:03:33Z")

</div>

Hello All,

After reviewing the AT cmd guide, adl user guide and SL8082 forums I have failed to get the low power or sleep mode to work.  
We have a microcontroller connected to the sierra module over the uart. I am intending to put the sierra module in low power mode with/without the gsm stack idle. With the gsm stack I intend to use an sms to wake up the module.

Could you tell me if this is possible and what how much power can I save with this. I thought using the AT+W32K and AT+WBHV I would see a significant drop in current consumption but it just around 10mA at 3V3. In normal mode the module uses around 40-50mA so just a 10mA drop is not really a saving in this case. The Power Consumption section in the datasheet suggests otherwise.

regards  
Ankit

---

<div class="post-metadata">

**Author:** ![awneil](https://avatars.discourse-cdn.com/v4/letter/a/49beb7/32.png) [@awneil](https://forum.sierrawireless.com/u/awneil)\
**Post date:** [February 3, 2015, 8:50am UTC](https://forum.sierrawireless.com/t/low-power-sleep-mode-with-wake-up-on-sms/7732/2 "2015-02-03T08:50:41Z")

</div>

> [@ankitparikh](#):
>
> it just around 10mA at 3V3. In normal mode the module uses around 40-50mA

How are you measuring that ❓

Beware that the current has very high peaks - you’re not going to see that on a meter!

For example, see: [antronics.co.uk/downloads/M1 … Traces.pdf](http://www.antronics.co.uk/downloads/M1306B_Current_Traces.pdf)

> [@](#):
>
> so just a 10mA drop

Eh ❓

From you quoted “40-50mA” down to “10mA” is, surely, a 30-40mA drop?!

But, yes - you should be able to get lower.

More details of your exact setup, and measurement techniques, would be needed…