New Bluetooth Low Energy modules

After the upgrade disaster of the "frimware" of a HM-10, I decided to retry with 2 new modules, this time from a european based reseller.

And since I also supported the airboard project, I decided to buy them in XBee format (without really knowing it, see below).

Both are based on TI chips (CC2540 for the first one et CC2541 for the second). One day I'll have to have a serious look at Nordic Semiconductor's offering (specially their new nRF51822 SoC) but the boards based on nRF8001 were out of stock anyway...

Bluetooth BLE Link Bee

The first module is a Bluetooth BLE Link Bee from DFRobot.


This module is the one officialy supported by the airboard. It comes with a very handy micro-usb port and integrated voltage regulator & leds. The "AT" physical switch is no longer in use with recent firmware.

I haven't explored much but, so far, I am happily surprised.

BLE Bee - Based on HM-11 Module

The second one is a BLE Bee - Based on HM-11 Module from Seeedstudio.

BLE Bee - HM-11

This is basically a HM-11 module with a couple of capacitors in the XBee form factor. Nothing more! Not even a "system led".

Price (even directly in China) is basically 4 times the one of the HM-11 alone and twice the one of the module above (but with fewer bells and whistles). This sounds odd but at least the embedded HM-11 seems genuine and the upgrade to the very latest firmware went without a hitch!!

But before I reached this stage, I discovered what the "Xbee form factor" was:

As a frenchman, I am a strong Metric System Advocate as it is better on all counts. But having a module using a 2mm (instead of standard 2.54mm) spacing was annoying (that said the HM-1x modules themselves use 1.5mm) as I had to create a makeshift pin adapter to be able to connect to the module. At least, I'll know for next time!


Despite following all the instructions carefully, I was still unable to create a iBeacon with these modules. Turned out that there is a bug with iOS 7.1.1 and iBeacons are not always detected. So maybe that was the signal to upgrade to iOS 8.

Using iOS 8.1.3, I was able to see the beacons... but with the HM-11 module, I had to more issues: It seems very unstable on a 3V battery (maybe a booster and/or a proper sleeping management is required) and I wasn't able to set-up the calibration value as AT+MEAS doesn't seem to work. Oh well...