Powering with 2 AA batteries


#1

I naively hoped I’d get long battery life out of the CRC2032 batteries, but seem to hit the wall at about 2 weeks (or less). Since I’m trying to monitor my garage doors, I’m hoping to get at least a year without worrying about changing batteries. It could be added to the New Years Day list! Otherwise, I should simply use Photons instead.

If I want to power my BluzDKs with 2 AA batteries, do I simply wire them (in series) to 3.3 and Gnd?

I’m wondering if there’s availability of a shield with female headers on the top for the BluzDK and room for 2 AA batteries on the bottom. Before I quickly design a simple board like this, I wanted to check for availability–it seems so obvious.


#2

Hmmm… that battery life seems a little low for a CR2032. Are you turning off the RGB LED? Are you enabling any peripherals that aren’t being used (Serial, I2C, etc.)? Battery life for a brand new and reputable brand of CR2032 should be on the order of a month or two with our current power settings. We are hoping to further that very soon when we release the ability to set the BLE transmit power.

Either way, we are very interested in looking at a AA or AAA battery shield. It should be a relatively simple upgrade from our current battery shield, and it would be a big boost in battery capacity. Once we get all the gateways out the door and release 1.2 of the firmware, we will have some spare cycles to start looking at this.

In the meantime, your wiring is correct. If you have the battery holder, you could even solder it directly to the CR2032 battery shield on the corresponding ports (or use terminal blocks if you want to make it swappable).


#3

@eric, I did not shut off the RGB LED. I just learned about that technique last evening and perhaps that will help significantly(?). I see in the docs about RGB.control(true), but do I also need to set the intensity or does it default to off once RGB.control(true) is called?

Also, I’m wondering if on power up, I’ll be able to see that the BluzDK is booting up via some initial flashing of the RGB LED or will it remain dark at all times at the above setting(s)?

BTW, I had turned off the LED on the shield.

One final (?) question, if I power via batteries, does the reference voltage for the analog inputs track this? I’m wondering about possibly powering thermistor circuits with a DO when a reading is desired and assume the output from the DO will lower as the battery supply voltage lowers. (sorry for the slew of questions)

(edit) I am not enabling any peripherals. I turn on a DO to provide power to my magnetic reed switches that are connected to a DI that’s configured with a pulldown resistor. I perform a check every 5 seconds and only push an update when the status changes.


#4

with the LED control you can turn it on and off as required, ie, start with it on so you can see connection status then turn it off ( take control and then set brightness to 0) later on you can turn it back on by setting brightness to desired level/set color or release control.


#5

@Hootie81, thanks for the feedback. It wasn’t clear to me and certainly a bit of testing would have quickly answered the question, but that’s not until tonight or later and I hope to hit the bricks running!


#6

I’d love to see a AA battery shield with a high efficiency boost converter on it so that the batteries were fully discharged.


#7

At this point in time, I’ve merely ordered (from Sparkfun) a Photon ProtoShield, some female headers, a 2-AA battery holder and a double screw terminal for my DI. Total cost per bluzDK will be about $6.25 plus shipping & tax. However, I am looking forward to a more elegant solution from bluz.