Battery Power for Dust Sensor

Other Hardware Sensors
1

Hello All,

I have a grove Seeedstudio dust sensor, all hooked up to my arduino Uno fine, and is measuring OK when powered via the USB, but I need this to be mobile, so need battery power. I have tried running it from a 9V alkaline pp3 battery and 4x1.5V and even 8x1.5V alkaline batteries (these are normally fine for running the arduino) but the values the sensor reports drops drastically so I think it is not getting enough power. The datasheet says that it needs 90mA, is that too much pull for regular 9V or alkaline batteries? I have seen versions online with an li-ion battery running at only 3.7V but with a board that boosts it up to output at 5V.

Do I need to get one of these systems or will it be possible to power using more commonly found batteries?

Here is the product and specification: http://www.seeedstudio.com/wiki/Grove_-_Dust_Sensor#Specification

Here is an online version using a battery: Hackster.io - The community dedicated to learning hardware.

Thanks All,

David

2

The 9V PP3 batteries are useless for circuits that require more than 10-20 mA.

The sensor needs 90 mA at 5 volts, but there are many ways of supplying that. The most efficient method is to use a switching regulator, like this one.

You can estimate battery life by comparing battery capacity in milliampere-hours (mAh) to the total circuit consumption in milliamperes. For example, AA alkaline batteries typically have capacity of about 2000 mAh, so an AA battery pack should power the sensor alone for roughly 2000/90 or 22 hours. Less if you also power the Arduino, of course.

3

Brilliant thank you jremington for the speedy and informative response!

I have ordered a switching regulator, it should arrive in a couple days and I will post how it goes.

Have a good day.

4

I've soldered it and it seems to be powering my setup (arduino uno, adafruit gps shield, seeedstudio grove dust sensor, all powered by 8xAA battery through the pololu regulator to the VIN). However the readings from the sensor seem very very high. The stated max is 8000, and my readings are between 10000 - 20000. If I power it from the USB without the regulator and going through the VIN then I still get high readings.

Any suggestions?

5

The GPS is not needed for testing the dust sensor.
Test only the simplest possible system.
Perhaps the dust sensor is not working correctly.

6

Thank you for that reminder! I was testing the most basic dust sensor code, but with the shield still plugged in. I removed the shield and tried the code again. The values are within the normal range now. This means that the shield itself must be causing a problem that increases the values so much.

Could the increase in values be due to the GPS shield using pin 8 for some reason? Or something to do with it affecting how long a loop takes to execute and how much dust is in the sensor before being read? I don't have a great deal of experience with the shield or the dust sensor.

I really want to be able to use the GPS shield with the dust sensor but I am now contemplating having one arduino for the GPS shield and another arduino for the sensor and try to communicate over Serial to send the values and log them on the shield SD card.

7

You may have power supply problems. GPS units consume a fair bit of current and you may be overloading the 5V output of the Arduino.

Can you post a hand-drawn schematic diagram or clear photo showing how everything is wired up?

8

I am not sure if it is a power thing as even running it from the USB there is this big discrepancy in values whether the shield is on or not.

Here is an image with the shield and the data below:

2448×3264 1.75 MB 

WITH SHIELD:
concentration = 32943.52 pcs/0.01cf
concentration = 57375.01 pcs/0.01cf
concentration = 25090.58 pcs/0.01cf
concentration = 30658.34 pcs/0.01cf
concentration = 35203.36 pcs/0.01cf
concentration = 30840.84 pcs/0.01cf

Here is an image without the shield and the data below:

3264×2448 1.72 MB 

WITHOUT SHIELD:
concentration = 0.62 pcs/0.01cf
concentration = 312.37 pcs/0.01cf
concentration = 1079.79 pcs/0.01cf
concentration = 471.64 pcs/0.01cf
concentration = 138.50 pcs/0.01cf
concentration = 0.62 pcs/0.01cf
9

OK so it looks like the GPS shield uses pin 8 for software serial communication with the arduino. So that means either switching to Direct communication or maybe using a second arduino to send the data over serial. Attempting that now and will post back results.

10

Sending data over Serial from another arduino using pin 0 and 1 (Rx and Tx) worked very well.

I used this very helpful post: Projects from Tech: Arduino: Serial Communication Between Two Arduinos

11

davidhunter:
I've soldered it and it seems to be powering my setup (arduino uno, adafruit gps shield, seeedstudio grove dust sensor, all powered by 8xAA battery through the pololu regulator to the VIN).

In post#1&2 you said you were getting a 5volt Pololu regulator.
And here you say you are powering it to the Vin.

That is not right.

Vin is pre-onboard 5volt regulator, so your 5volt rail will be 4volt at best.
This will give you wrong readings.

You have to connect a 5volt DC/DC converter to the 5volt pin.
Leo..

12

Hi Wawa, thank you for that advice. I guess I could power the arduino with a battery through the 2.1mm jack and then power the dust sensor with the pololu 5v regulator.

13

If you power both the Arduino and the dust sensor from the 5volt DC/DC converter, your batteries will last longer.
Leo..

14

ah ok so power the arduino through the Vin and the dust sensor directly from the pololu regulator. cheers

15

No, I did not say anything about Vin in post#12.

Read post#10 again, especially the last line.
Leo..

16

OK, Leo, I am slightly confused then what is the best way to power this using the pololu 5v regulator. As you can probably tell I don't have a huge amount of experience with Arduino, especially in terms of power and peripherals. Previously I have only ever needed to run from a 9v wall adaptor, so battery power is a new thing for me.

Thanks

17

The Pololu DC/DC converter converts any battery voltage (6 to 30volt) into a stable 5volt that you can directly connect to the 5volt supply pin of the Arduino.
Leo..

18

OK, so like this: Connecting power source to Arduino's 5V pin - Electrical Engineering Stack Exchange

19

When powering from 5V to the power header, I would add a diode from 5V (anode) to Vin (cathode) to avoid reverse driving the 5v regulator too much.
See Figure 1 for an example discussion of why this could be needed.
http://www.linear.com/docs/2946