Powering photon through 3xAAA issues


#1

Hi, I’m trying to power my Photon through a 3xAAA battery pack with an on/off switch.
It appears to work for the most part, but after a period of time (sometimes 3 minutes, sometimes 30) the Photon will go to breathing white, which I understand is Wifi Off.

I’m thinking that this has something to do with the power source, so I’m hoping those who are experienced in this area might be able to tell me:

  • Am I underpowering the device with this setup?
  • Is there something else obviously wrong with how I have this configured?

Attached is a photo of the current config.

Thanks in advance!


#2

Have you measured the voltage that you are getting from your AAA setup? The minimum might not be met all the time. Remember that there are 2 chips under the can, a uProcessor and a WiFi unit. One might be happy with the voltage the other one not so happy.


#3

@jeffwmiles, the Photon onboard SMPS requires 3.6 to 5.5v to operate. With wifi idling, the Photon consumes about 80ma. You need to make sure that the batteries are supplying the necessary voltage AND current.


#4

Would using a capacitor in the setup assist in ensuring the Photon gets enough power when the Wifi chip spikes?

I know with some wireless chips its recommended to add a capacitor so when it powers the radio the surge of power can be smooth if that makes sense?


#5

The batteries will certainly last longer if you add a capacitor.


#6

Thanks for all the replies. I’m measuring 4.05v from the battery pack. Unfortunately the multimeter I scrounged up doesn’t appear to take amperage measurements so I can’t tell if it’s providing enough.

A capacitor sounds like something I should look into; so far I’ve gone from zero knowledge to 4 or 5 broken toys scavenged for LEDs, battery packs and switches and a functioning Beakn.

I’ll have to see if I can find a 4xAA battery pack from some device.


#7

I’m doing something similiar, but put a capacitor and 5v regulator in the line to help out. This will give you consistent 5v power over a range of battery voltage. There may be a more consistent way to do it, but this is a simple circuit which seems to work very well for me.


#8

5V regulator wont do anything in this case , the nominal voltage is below 5V.

Seeing that @jeffwmiles measured 4.05V from the battery pack, which I assume is nominal (so not under load), makes me think the battery pack dips below 3.6V under load (WiFi transmitting) causing the photon to abort the WiFi usage (not sure but seems plausible to me). Can you verify this behavior @jeffwmiles ?

TLDR; Does it drop the WiFi during sending or at random moments?


#9

As @TheHawk1337 said the source is less than 5V already but even with higher supply voltage there is no need, since there is already a 3.3V regulator on the Photon.
So no need to add another one, unless you want to power other 5V devices off the same source.

Unless you meant a 5V+ stepup converter, but then I’d rather suggest to donate an extra battery :wink:


#10

According to the docs, the recommended max input voltage is 5.5V (and the maximum max input is 6.5V). So using 4xAA batteries could damage the device or am I wrong here?


#11

I’d think that 4xAAs are safe to use - the Particle Maker kit even comes with a 4xAA battery pack :wink:


#12

I think TheHawk1337’s assessment is correct in using the 3xAAA and the voltage dropping.

I managed to find and wire up a 4xAA pack, and it was stable and worked well. It only lasted about 20 hours worth of runtime though, so I’ll be looking at the capacitor idea if I can find one somewhere, as well as rechargeable batteries and some kind of solar kit.


#13

You can also win a lot of battery time by turing off the WiFi module when you don’t need it :smile:


#14

4AA batteries will in fact work, but I put a 5v regulator in as a safety net. Doesn’t cost anything, and also allows you to power other 5v devices when running from battery (say some NeoPixels which don’t have a regulator and tend to frown on anything about 5.2v or so).

It was a suggestion for a 4AA battery application.


#15

I’m using this as a Beakn, so I don’t think turning off Wifi fits with the use-case; that’s why I’m looking to solar as a recharge source.


#16

Hmm, interesting. I think it would be possible to make the photon check the beakn status once a minute to save power but this would add a lot of difficulty.

Like the project though! :smile:


#17

I did the same thing, using 3 AA batteries to power the photon. It ran just fine in this configuration. I turned it on and off every 10 minutes, for only a few seconds, and it lasted for well over a week on the same batteries before I turned it off. I did not use a capacitor or voltage regulator. I used new, good quality, regular batteries.

Hope that helps.


#18

Can I use a 9v to power the photon ? Seems to work ok when I do…

Or can I use the PowerShield with a 9v? I don’t need to charge a battery, just power the photon.


#19

Checking the docs hardly ever hurt anyone… :wink:

Taking the above into consideration, I’d go with a no. No, you can’t power your photon with 9V, unless your primary goal is to destroy it in the process.

https://docs.particle.io/datasheets/photon-datasheet/#absolute-maximum-ratings


#20

Thanks, I missed that…