RD3152MMA7260Q and Wireless Interference

[gerickson]

After about a week of successful use, I ran into an odd problem today with the RD3152MMA7260Q "ZSTAR" evaluation system.

In the week prior, I had been successfully running experiments in one room of the building, in which the computer, USB stick, sensor stick and the device-under-test were all colocated in the same room.

Today, based on success there, I decided to move to a different lab and conduct another series of tests. Bringing the USB stick, sensor stick and computer to the new lab, I attempted to calibrate the sensor and found that all the communication with the USB (or perhaps both USB and sensor stick) was garbled (packets missing information, particularly, the 'v' "extended data" packet).

I tried moving the USB sensor stick back to the adjacent lab while leaving the device-under-test and the sensor stick in the new lab. To my amazement, it worked successfully.

So, my question is, what sources of interference are likely to influence the USB-to-sensor board communications? Moreover, what would cause interference when both were co-located in the new lab vs. being separated some 10-15 feet by a wall where no interference was observed?

[bigmac]

Hello,

I wonder if the interference might be due to a close by (to the USB sensor stick) Bluetooth device in the second lab.  There is some potential for interference.

Regards,

Mac

[gerickson]

An excellent suggestion; however, I took the advanced precaution of disabling all 802.11x wireless basestations and transceivers, all Bluetooth devices and all 2.4 GHz and 5 GHz cordless phones as part of my troubleshooting procedure.

That the USB and sensor sticks worked in the first room in the presence of such active devices seems confounding.

I seem to recall reading something in the ZSTAR manual about configuring the communications channel. I may give that a shot tomorrow and see what results. Failing that, I may just run back-and-forth between the two rooms, taking measurements from one while running the device under test from the other. While less than ideal, my focus is on the application rather than debugging RD3152MMA7260Q.

[ok2ucx]

Hi, you recall this exactly - you may force a specific channel (e.g. via HyperTerminal and confirm via Debug mode - command 'U')

5.4.6.1 Forced Channel Number Selection

In order to allow effective testing and debugging, additional commands have been added. If, before a connection between the USB stick and Sensor Board is established, any hexadecimal number command (‘0’ through ‘9’ or ‘A’ through ‘F’) is sent, the connection will be established on this specific channel number (0 to 15). Any new channel can be selected, sending the new channel number command. The selection becomes effective when the new connection is being established. The return to the automatic mode (where a random channel with the minimum energy is selected) can be forced only by a complete software reset (i.e. removing the USB stick from the USB slot).

Playing with channels you may find that some channels are 'better' than others mainly because of interference. Maybe your second room has different interference/noise levels, thus automatic channel selector chooses something less reliable than in a first room.

I'm not aware on any other specific interference source (beside those you mentioned).

Hope it helps,

regards Pavel, ok2ucx

Freescale Roznov p.R., CZ

[Hanselmanne]

Hello!

I am using four Zstar sensorboard-USBstick-combinations in parallel. Is it possible to speed up finding connection? First I plug in the USBsticks, then I switch on the sensorboards one after another. The first and the second sensorboard are always connected very fast. But the third and the fourth take more time.
I already forced the four boards to use different channels to decrease the interference between them, but that did not help. Can I force the Sensorboard to use a special channel? Or what else could I do?

Thanks,
Anne