Hello All,

I'm working on a project which needs to wirelessly send data from a test rig to a computer inside a building, doesn't have to go far but is through a wall. I was thinking of using a PIC microcontroller and two xbee modules.

That is: voltage->pic->xbee->xbee->pc

Might need another PIC between the xbee and pc but I'm not sure about that yet.

The modules I've been looking at are these.

I have two questions really

1. What microcontroller would you suggest to measure a voltage and communicate with the xbee? I was thinking a PIC 16F876
2. Can these modules be easily interfaced with a PIC? From what I'm reading in the spec sheet I just wire it up to the pic via the usart pins and away we go. Actually that leads to another question, what is the best why to change the voltages from 5 to 3.3 and vice versa for the signals, is there a chip that does this?

I notice in this tutorial, the guy use's a breakout board. Does this mean the xbee won't fit directly into a breadboard?

And at the risk of asking a stupid question, would this be the correct aerial for the module?

Any help much appreciated,

Thanks,
Oisin

 

Hi ozirock,

For question 1:
The PIC16f876 has a 5 channel, 10 bit ADC convertor to measure voltage so it should work fine. It has a USART port so it should communicate with the XBEE module just fine.

For question 2:
I don't think you will need any level conversion from 5V (PIC power supply) to 3.3. I believe if the XBEE client receives anything over 3.3, it will be a logic 1. This might need to be double checked though.

In addition, since the 2nd XBEE module will communicate with the PC, you will need a 3.3 V (output of XBEE) to a RS-232 level converter. The MAX3232 chip from MAXIM does exactly this. You would input the 3.3 V TTL signals from the XBEE into the MAXIM and the output of the MAXIM chip will be your correct voltage levels for RS-232 that the PC will be able to read.

 

I am also searching for some data related to Zigbee as i want to convert my RF module into Zigbee using Zigbee stack provided by TI or ATMEL or MICROCHIP.