Redbear Blendmicro (nRF8001) - constant Tx power / Direct Test Mode

[named.kai]

Hi,

I am a new comer to the nRF8001. I am using Redbear Blendmicro (nRF8001) for my project.

I have wrote a apps to scan my Blendmicro(s) and acquire their RSSI value so that the distance between BLE and smartphone could be deduced.

However, I found that the RSSI value is fluctuated if there is slightly movement either to the Blendmicro(s) or smartphone. Don't know if their is any mechanism to varying the Tx power internally.

I am now want to set the Tx power to constant for the test. I have read the manual and found that their is a TEST mode to the Blendmicro.

Could anyone let me know how to setup the Blendmicro to TEST mode?

Regards, Angus

[David Edwin]

The default TX power is 0 dBm. The test mode that you mention is typically used for RF compliance tests. Look at the ACI Test command in section 24 of the nRF8001 datasheet.

It is also likely that your RSSI is changing due to the antenna design used, on the blend micro and the smartphone, additionally reflections and multi path influence RSSI, so even if the transmit power is the same the RSSI can change.

[named.kai]

Hi Star,

Thanks for the reply. I will try to modify the code at later on.

Besides, as mentioned, the influence may be caused by reflections and multi-path, do you think the fluctuating RSSI value may due to Doppler effect also? If yes, the estimated distance is valid only if the transmitter (Say, Blend micro) is static !!

Regards, Angus