Atmega328p LoRa Low power use!

By pbecchi at 2018-03-15 • 0 collector • 110 pageviews

Hi I received few of these boards one week ago . Boards are good but documentation and examples are a little pour!

I am testing now the board in LowPower mode using LowPower.h and I am getting an 1mA minimum average consumption during sleep without the power led(2.5 mA with power led). I was expecting much less ( from 1 to 10 uA for the Atmega32 + about 250uA for the Sx1728) ! Is this due to any particular board component? There is any way to reduce that (other then taking the led away)? Can you send me password to access board schematic? Thanks

8 Replies | Last update 4 days ago
2018-03-21   #1

Hi, Sorry never try the low power for this before, so no idea now, will test this and reply you later. 

The wiki login info is sent together with your order tracking info email, please check there.

2018-03-23   #2

Thanks, let me know, the board is ok for my project! I want to make a bulk order if I can reduce the power.... I can I get a quotation for 100 or 200 ?

2018-03-27   #3

Hi, we will need time to check the low power, not really good at this. We have a replacement IC instead of Atmega328, which should work fully same. but 1.2 usd cheaper. Totally each board could be 1.5-2 usd cheaper for bulk I think. 


30 days ago   #4

Just a couple of suggestions for reducing power drain:

Power led drain about 1 mA ,it will be nice to have a way to disconnect it. Battery voltage is measured with a voltage divider with 2 10k resistors. This generate a continuous drain of about 0.2 mA . I suggest to use two resistor of 100k.

The new MCU will have same low power performances as the atmega328 ?

Thanks

7 days ago   #5

we have just done some test today, result is here. 


http://www.electrodragon.com/w/Low_Power


On transmitter mode, should be 9.5mA regular standby, remove all extras, can reduce about 4 mA maxium.


if use a blank board without lora module, is about 6.1mA, could be lower down to 2mA if remove extras. 


The lora module should cased about 3mA when standby.


So regular 9.5mA -> remove all extras -4 to 5mA -> remove lora module -3 -> 2mA. More or less like this.

7 days ago   #6

Ah, just posted a "me too" to access the schematic, when I spotted this thread.


(btw, my search for Loraduino only came up with one other thread which was not relevant)


Like the original poster (and many others), I have got good low power results with pro minis, with the "remove the led hack", but mostly by the use of the LowPower.h library, which is pretty awesome and taught me a lot about accessing directly the registers on the mega328p.


I mean the table they posted on the wiki is fine, but without including the use of the LowPower libary then I think it is a bit of a wasted exercise.


I actually started this reply because it dawned on me that, given that I too could (eventually) be ordering 100's of these things, it might be in Electrodragons interest to produce something which was low power to start with, the twinkly leds could be something that users get to add themselves. 


Its just a thought, but users like us mangling your carefully thought out boards on arrival just to remove components would seem on the face of it like an opportunity to reduce costs.


caveat : I'm not an electrical engineer, and realise any EE with a well stocked mind could probably shoot me down.

6 days ago   #7

We will keep doing this test, with lowpower library too.  

Any suggesttions. or test need please let us know we will do. Any updates will update this thread and also on wiki.


4 days ago   #8

If I compare correct, pro mini use regualtor MIC2505, which quiescent current is 5uA, but only 150mA delivery, the upgrade version MIC2519 is better 8uA/500mA. Our current use is AP2112 but 55uA quiescent and output up to 500mA. Which also add this to test later.

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