TI CC1101 Radio Project

[LinkMTech]

Yeah, I bought a pair of them MRF's too but only ended up staring at them cuz they look cool.

[ecoli-557]

Yup. I should have my radios in waiting for me Monday. Then I can see about playing with them.......

[LinkMTech]

Steve,
I remembered unsuccessfully trying to solder rework wire to the module's pads only to damage it.
Do you make your PCBs?

I have some older revision PCBs with footprints for these module if you're interested. No strings, just willing to help.

[ecoli-557]

I would REALLY appreciate that. I just looked at my radio development 'kits' (2) and all I got was the module with an antenna! It looks as if these plug into something else........
So, it looks like I am going to make a cheap proto pcb....... I use Eagle, what do you use?
Regards,
Steve

[LinkMTech]

I use Express PCB and Pad2Pad for my boards.
Which kits did you order?

PM me your address so I can mail you some PCBs.

[ecoli-557]

I ordered the CC1101EMK868-915 from Mouser. Then just today I ordered the SOC-BB also from Mouser.
The SOC-BB should (?) allow me to plug in the radio modules, power via battery which is kinda weird, but will allow me to SPI-communicate to the radio.
I have been told the TI will work for me to do my coding, then move to the Anaren part which has the TI part and is FCC licensed.

I don't think I could use the Pad2Pad file to create my foot print for the radio, I will double check.

Thanks for the offer on the boards, but as I will need to generate my own with the radio, I think I should just muddle through and do it myself.

I would like to know more about the RSSI and actually how to use the data, were you successful in doing this? The other post made it sound as if going FSK would be easier.

[LinkMTech]

I didn't get to the RSSI function but didn't see it a problem since it means reading a register during the RX mode. The level range is pretty good and linear.

The RSSI value is available to be read from a register when the module is in RX mode. This value varies with the other transmitters signal strength reaching it. The value will of course be digital but have a minimum to maximum value. There will always be some value there due to noise or other transmitters on same channel.

Here's a simplified example of using it in your app, keeping the timing between TX and RX from module to module in mind:

Base changes to TX mode and sends addressed query message to sensor
Base changes back to RX mode and begins reading RSSI register

Addressed sensor receives message and changes to TX and sends an ACK of some sort
Sensor module reverts back to RX mode

Base monitoring the RSSI records the value during valid message from sensor.

Since you want to "talk" to the closest sensor, query the others in the same way then choose the one with the highest RSSI value after comparing all RSSI's.

This is a general description of the signal strength. There are other factors that will cause it to vary like interference, fading, etc. but it's a pretty good indicator to work with.