Hello - I am trying to figure out how to read the current battery charge level via the Xiao BLE Sense with a 3.7V Lipo battery connected via JST to the Xiao Expansion Board. However, I am confused by the various discussions around this topic in the past and the apparent lack of a clear solution (sug…

Thank you! I will give it a try. Is the mbed-enabled strictly necessary if I only want to read the battery or was this limited to other parts of your reference project? My own project is running non-mbed

I have tried to extract the relevant portions of your reference program for the battery reading only (thanks again for the guidance!). I am using the below sketch (mostly extracted from your reference file) which compiles properly. However, when trying to read the battery I am only getting a readin…

The link I provided is for the nRF52840. I’ve made the necessary adjustments to adapt it for the XIAO_BLE_Sense (SAMD21). #include <Arduino.h> #include <Wire.h> #include <U8x8lib.h> #include <ATSAMD21_ADC.h> #define VBATT A3 // Central battery voltage (voltage divider required on XIAO…

I think I might be misunderstanding something. Is the XIAO you’re using an nRF52840? Since a buzzer circuit is connected to A3, it can’t be used for the battery voltage ADC. I recommend using A0.

Yes, the XIAO is using the nRF52840 chip. I tried switching to A0 but it still shows the same (<0.1L despite a near-full battery)… which means it does pick up something but not the battery itself. I tried looking in the Expansion Board intro but it doesn’t appear to link directly the LiPo battery i…

I wish the new expansion board would have a battery management chip on an IIC line [image] XIAO Expansion Board & Base for Battery XIAO [image] not sure if you have seen this. To summarize, what you are trying to do is create a analog sense of a voltage …

Thanks a lot for the input. I am very new to this whole world with no real prior knowledge so I don’t think this sounds feasible to me. Does this essentially mean there is simply no simple / established way to measure the battery charging level for Seeed / Arduino projects? How do you deal with thi…

[image] SeeedNoob: I am just honestly baffled why something that seemingly sounds so simple appears to be so complicated! yes… we have been wanting this forever… the basic answer is that if voltage management was a standard thing… it would take away a GPIO pin from the board that someone else…

SeeedNoob, I mistook it for the SAMD21 and accidentally sent the wrong example. The attached sketch is currently running on an expansion board connected to a battery right here on my desk. It definitely works. However, on my expansion board, 1000k and 680k resistors are connected to pin A1. The c…

Xiao BLE Sense Battery Charge Reading

Products & Technology XIAO

msfujino July 29, 2026, 10:31pm 2

Please take a look at the image in Post #1 at the link below.

The battery voltage connected to the JST connector on the XIAO Expansion Board is not directly connected to the XIAO. Some modifications are required to read the voltage.