Short question - how do I send data as GATT characteristics from a peripheral BLE device (Android UNO + HM-10) to a central device (i.e. an android smartphone?)

I'm working on a BLE peripheral as a learning project right now - I'm using an Arduino Uno and an HM-10. It's going well so far - sensors are working and I can send this data from the Arduino Uno to Android using an HM-10 BLE module (actually a CC2541 clone) on the standard service and characteristic for this device:

  • Service UUID: 0000ffe0-0000-1000-8000-00805f9b34fb
  • Characteristic: UUID: 0000ffe1-0000-1000-8000-00805f9b34fb

Working in this way the HM-10 emulates a traditional bluetooth serial connection. All good so far!

What I would now like to do is send the data using accepted GATT services and characteristics. For example lets say I would like to use the Running Speed and Cadence service to send my data in a way that can be viewed by any compatible app. I would need to change the service to 0x1814 and the characteristics to:

  • Cadence: 0x27A8
  • Velocity: 0x27A6
  • Gradient: 0x2763

I believe I could do this by using the AT commands:

  • AT+UUID0x1814
  • AT+CHAR0x2763

I think I'm OK with all of this so far, but what I cannot find guidance on is how to define multiple characteristics, and how to send my sensor data to my central device as GATT characteristics.

For example my speed is 10kmh-1 and my cadence is 80 - how do I specify the GATT characteristics for this and notify the central device when they change? Also bonus question - can I include an additional characteristic for gradient?

I've thoroughly searched but cannot find anything on this. Thanks!

  • \$\begingroup\$ This has been edited to remove the arduino tag, but if any respondents could keep in mind that I'm working in the Arduino IDE I'd appreciate it :) I'm new to this and likely to be confused easily! haha. \$\endgroup\$
    – c.early
    Commented Aug 9, 2017 at 11:55

2 Answers 2


AT+NOTI unfortunately is not the correct command. The manual states:


If this value is set to 1, when link ESTABLISHED or LOSTED module will send OK+CONN or OK+LOST string through UART.

I believe, it's not possible to do what you want. I've been searching my whole day, but there is only this one custom characteristics, and you can change only the short UUID. I found no way to get data from other UUIDs in Central mode.

Here is some more info: BLECentral - HM-10 BLE Module

Edit: With new Firmware version > V546, there is a possibility to use 128 Bit UUIds. A readme + the needed software is located here: jnhuamao Website. And V605 states:

hm-10 readme

Unfortunately, I did not succeed to update the Firmware yet.


I think you're looking for AT+NOTI. Check the datasheet for specifics, but notify is what pushes from slave to master.


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