Yesterday, with the whole group, we made a lot a research for our project. First of all here a table of the wireless solution we could use:

Type         Range                 Data Rate               Average consumption    Band        Get through water    Get through concrete    Price
Wi-fi          32 – 95 meters     2 to 7000 Mbit/s      317-324 mW                    2.45GHz               ?                               ?                      ~20€
Bluetooth   5 – 100 meters     1 to 100Mbit/s        15-24 mW                        2.45GHz              No                             No                     ~15€ (RN42)
ZigBee      30–500 m             250 kbit/s               125–400 µW                    2.45GHz              No                             No                     ~20€
Dash7       250-1000 m          200 kbit/s                30–60 µW                       433,92 MHz         Yes                            Yes                    ~40€ (wizzimote)

The Wi-fi and the Bluetooth don’t fit our consumption conditions. The best would have been the Dash7, but there is no kit that are fully implemented, with all the functions of the Dash7 protocol. For the ZigBee, everything is already implemented but it doesn’t fit our range conditions.

So Dash7 it is, and we are looking forward to Wizzilab and their Wizzimotes. We are going to do tests, but if we decide we cannot use it we would have to do the radio layer by ourself.

So for the “stone” here an idea of architecture:
– The wizzimote composed of the TI CC430F5137, we use the CC430 to add our own program (we have approximately 10Ko left on the chip for it)
– A FRAM that have the advantages of a flash (persistence of the data, with no additional current) and the advantages of the RAM (speed). Here will be stocked the messages.

Rest to specify : the type of bus, and the batteries we are going to use.

Hubert Lefevre

Facebook Twitter 

Commentaires fermés.