ABKey01 battery level advertisement


I am trying to get the battery level to be sent with the advertisement package from the ABKey01.
I see that Eddystone-TLM supports this by default, but the ABKey01 only support iBeacon, Eddystone-UID, Eddystone-URL and Line Beacon.

I know that if I connect to the ABKey01 I can get the battery level, but that will be a little problematic since I only want to see the advertising packages.

Is there a new firmware for the ABKey01 that supports Eddystone-TLM?
Or do I have to modify the firmware myself so it can adverisen the battery level?
If so, how to I “easily” create a new firmware for these?

(I found a alternative cheap product that uses Eddystone-TLM, the Minew C6, but I wanted to use the ABKey01 as long as there is a solution)


Hi john,

ABKey01 advertises eddystone-TLM packet between about 15 other packet. It works for all advertising mode. You should filter out the TLM packet and parse it

Hi April,

Thank you for your reply.
I modified the scanner a bit and focused only on TLM packets. Now I found them. Thank you very much for the information.

This is what I have figured out up to now.

key nr1:

Combine and convert byte 3 and 4 to decimal and divide by 100, since the specification says Battery voltage in 1 mV per bit. Ref: https://github.com/google/eddystone/blob/master/eddystone-tlm/tlm-plain.md#field-notes
09f6 -> decimal = 2550 / 100 = 2,55 = 85% (got that percentage number from the app)

key nr2:

Combine and convert byte 3 and 4 to decimal and divide by 100, since the specification says Battery voltage in 1 mV per bit.
0b04 -> decimal = 2820 / 100 = 2,82 = 94% (got that percentage number from the app)

270 mv = 9% difference
so 30mv pr 1%

But I doubt the ABKey01 will run on 30mv, so I checked the datasheet for the dialog14580. Ref: https://support.dialog-semiconductor.com/downloads/DA14580_DS_v3.1.pdf

So my next question is:
Are the ABKey01 running in a boost converter application or buck-converter application?

I hope it is using boost converter, since it would then allow a battery voltage of minimum 0.9V and not just 2.35V

BUCK mode is for 3V battery and BOOST mode is for AA battery (1.5V). ABKey01 uses BUCK mode.

Please also check our latest ABSensor N01, it’s based on nRF52810 and support 1.7V ~ 3.6V. It’s also same shape with ABKey01.

Ok, so just to confirm. The ABKey01 will stop working at 78%? (2.35V)
If not how low will it go?

It remaps battery percent from 2.2V (0%) to 3V (100%)

But that does not look correct.

If you see on what I wrote about the voltage and percentage.
From nr1 I get 2.55V from the TLM and 85% from the iphone app.
And nr2 gives 2.82V from the TLM and 94% from the iphone app.
Which remaps to 30mv pr %

So if what you say is correct it should be 8mv pr %.
And then I should get around 44% instead of 85% on nr1, and around 78% instead of 94% on nr2.
Maybe there is a bug in the AprilBeacon app?

It’s not calculated with linear percent. a little complex

Ok, for non-linear I don’t have enough data.

I will come back in 6 months or so.

Thanks for your replies