I'm going to build a 900HP network that will have up to 500 end devices in the future (right now only about 100).
I'm using both the
- XBP9B-DMST-002 (XBee-PRO 900HP (S3B) DigiMesh, 900MHz, 250mW, RPSMA, 200Kbps)
- XBP9B-DMSTB002 (XBee-PRO 900HP (S3B) DigiMesh, 900MHz, 250mW, RPSMA, 200Kbps, 32K Programmable)
These end devices are mobile GPS units that are placed in vehicles moving only in a delimited area.
Also i'll have fixed solar stations that will gather sensors data using a 32Kb programmable 900HP.
The fixed stations will be placed every each ~5 Km (depends on the XBee range tests that i will make).
The vehicles must send data using the nearest fixed station. And the final destination of every vehicle and fixed devices data is a main computer that will centralize, organize, cache, and send all the data to the internet.
I've read the XBee documentation but i still don't have all the parameters defined, here are some considerations:
- I thought about using DigiMesh, not sure why. (Maybe i should think of P2MP ?)
- I will use the 200 Kbps firmware (cause i need it for DigiMesh), although 10 kbps would be sufficient for me.
- I want the fixed stations 32 Kb programmable modules to be remotely updateable (OTA).
- I want every vehicle device (non programmable xbees) to be configurable and firmware remotely updateable (OTA)
- The vehicle xbees are going to be placed in a generic board with a secondary mcu, and i'm going to program it to send GPS data from the vehicle thru the XBee network in programmable intervals (from 1 sec to 10 min), and they'll do that autonomously (i don't want the central computer to poll data from every end device cause it would take forever and also would generate unecessary overhead in the network). Problem: probably all the end devices are going to send it's GPS data at almost the same time (cause it uses the gps time), unless i put some randomized miliseconds delay on the firmware.
- I have not decided if i should use AT or API modes, which one do you recommend for my case ?
Do you have any suggestions, thoughts, recommendations about my setup ?