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Asked — Edited

Help With Synapse And Xbee Rf Modules

Ok, after 2 days of netting the same results, I'm ready to ask for help. I had been planning on replacing my Bluetooth with Synapse RF Modules and decided to tackle it first thing yesterday.

I have been using both Xbee's and Synapse modules successfully for a couple years with other microcontrollers. I also know how to connect and use USB FTDI adapters directly with serial ports on microcontrollers.

Unfortunately, none of that has helped me get my EZ-B to communicate any way other than Bluetooth. Whether I try Xbee, Synapse or a direct FTDI connection, ARC comes back with a msg that I have v8.5 firmware and then a 2nd msg that it could not connect. I assume this is because the serial data is being corrupted somehow. I am using v16 firmware on a 3A EZ-B board. My ARC is current at 2012.08.27. I always make sure the virtual serial port is config'd for 9600 baud. I'm using the EZ-B's +5, +3.3 and Gnd for the onboard RF module adapter.

Just to verify I understood what pins were In & Out on the EZ-B connector where the Bluetooth goes, I got out my trusty old Tektronix scope and made sure. I am using a Level Converter to match the EZ-B's 5V serial signals with my Xbee and Synapse's 3.3V levels. It should be ok. I've used it for other things. Besides I can see a short serial burst come out of the EZ-B and go into my RF module when I power the EZ-B on.

Not sure how that power up serial string is used, but here it is in case anyone is interested: P..*5..i.Robot
or in Hex: 50 D5 C9 2A 35 15 15 69 B5 52 6F B5 52 6F 62 6F 74

I also verified each of the 3 ways I tried could send & recieve data on a loop back connector with a terminal program.

I know it is possible to use either an Xbee or Synapse in place of the Bluetooth. I carefully studied several projects doing it. So, I must be missing something! Should I have to do anything in ARC other than connect to the vitual com port like I do with Bluetooth?


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Hi Marv,
Im also using synapse in my project and have had the same problems you are having.
My problems where in the shifting from 5v to 3.3 and the code on the nodes.
But the manual from solarbotics fixed everthing so...

the manual

I hope it helps as it did for me.
Hey, thanks! Yes, I'm familiar with Solarbotics write-ups and videos. Good stuff. I've reread the one you mentioned several times trying to see where I was going wrong. I am using the same scripts in my Synapse modules.

By the way, I'm using Synapse RF266 modules, which are plug compatible with Xbee adapters and shields. Mostly because I already had a lot of those adapters from my earlier Xbee and Synapse projects.

A little while ago I found a 5V FTDI Basic adapter in my collection, and low and behold it works just fine with the EZ-B. I had tried a 3.3V FTDI coupled to a Sparkfun Level Converter, and it wouldn't communicate with the EZ-B. I had been using the same level converters between the Xbee and Synapse and EZ-B, so I'm sure that's why they wouldn't work either. Not sure why the Sparkfun Level Converters won't work. I have used them before with other devices like my wife's Roomba.

As far as using a level converter between the Synapse and EZ-B, I'll probably just try a pair of resistors like Solarbotics suggests.

Your R.O.O.S.T.E.R. project is very impressive. I'm in awe. This 4WD Rover is the farthest I've gone in Robotics. All of my other projects were of the home automation type. But I had to give most of that up when we moved into a condo.
Great that you got it working ^^, took me a lot longer >,<"
I'm working for quit sometime on my robot (already have hit the one year mark, 2 months ago).
Most time is lost to waiting for parts to be delivered. But once I get my extra battery I'll make
a video. No more browning out:D !