Awesome Find Rogue !
That’s what was frustrating me… SparkFun has had Smirfs for ages but they are always @ $40 to $50 a unit… seemed frustrating when the uC is less than half that price.
So now we are looking at :
115K Serial with no Servo contention, Computer->Robot with a BBB $16 + Cheap BT $10 = $36 a unit
Thanks - Very Nice !
You have a point voodoo
But its not BT so - the computer would need a tranciever too no?
However, I bought 4 msp430s
So maybe the least expensive robust solution is :
$5 msp430 + Rogue’s Cheap BT find $10 = $15 per unit (woo hoo)
Seems a very “Swarmable” price
BT all the way !
Thanks for all the information CTC and advice. I have successfully avoided Xbees because of their price and voltage requirements. I am interested in swarming, but all the information will either be directed by the computer or routed from one robot through the computer to another robot…
Its encouraging you have had solid results with both, now to see if Rogues super cheap BT example is just as solid !
Lower still !
And here is SMD BT for $6.60 - although it looks as if default setting would need to be re-programmed if you want 115K
So I could print my own interface to plug into a msp 430, and that would be ~ $10 per (uC + BT) !!
$40 for a 4 bot swarm (not including servos, wheels or batteries)
Seems doable…
Next BT Question
It says these modules have password 1234 … which is fine, but what about BT identifiers? Do they all come with unique IDs like ether MACs? or can the id’s be programmed?
MAC’s
Everyone gets their own mac address. I will do some tests but I am pretty sure they will just show up as different com ports and thus, eclipse or processing would simply run multiple serial lines. --one for each unit.
you typically can’t
you typically can’t reprogram a bluetooth MAC address, but they should be different. on the other hand you can likely change the module name which shows up during a search, but that feature is module dependent.
Different serial lines would be great !
MRL could just create a new serial line for each Bot (if that is the case) Swarm On !
I’ve found the bare
I’ve found the bare Bluetooth modules are difficult to solder even with a microscope and surface mount soldering station, I really don’t like the half via pins they use. The four dollar premium for the presoldered breakout board is worth every penny to me.
in windows each bluetooth
in windows each bluetooth device with serial port profile will have a unique COM port associated with it. You can discover it by right clicking the bluetooth icon in the windows tray and clicking Show Bluetooth Devices, then right click the bluetooth device and click properties. Then by viewing the different tabs of the properties window it will show a COM port for the Bluetooth services offered for that device. Helpful when you have a swarm and you need to determine which device is communicating on which COM port.
Noted
Thanks - I’ll pay the extra $16 to save hair-pulling
Nice !
By the fact that Windows (or other OS) understands them as seperate devices was the part I was concerned about. When I get the pieces together, I suspect that MRL will ask each uC who it is. That way regardless of how the OS identifies the BT/Com devices, MRL will identify with the uC’s response and bind them with the appropriate SerialService during runtime.
In the past I have seen com ports register differently depending on bootup, and many other variables.
But having the uC respond (as long as there IS a connection) would allow identification of the each uC consistently…
Good for when the bots have slightly different capabilities, e.g. IR sensor on bot #1 vs WiiDAR on bot #2 vs Servo gripper on bot #3…
Be warned. Don’t expect
Be warned. Don’t expect unique MAC addresses from cheap BT modules made in china.
I got a brand new Bluetooth Bee from Seeedstudio and wonder why my Android phone won’t pair with it because of a duplicate MAC address.
Good Point
Although @ $10 bucks a pop, I’m willing to risk it (possibly attempt to hack a MAC if it comes to that)
Just ordered 6 from Rogue’s suggestion & link - http://www.goodluckbuy.com/arduino-serial-bluetooth-rf-transceiver-module-rs232-with-backplane-.html
Now just got to wait 7 days for by “GOOD LUCK BUY” blue tooth to arrive…
Heh, I hope its a “good luck buy” 
it comes with 2 trancievers,
it comes with 2 trancievers, so you have all that you need.
I have to say, thats a
I have to say, thats a really good price.
Wow - This looks impressive although its not BT
http://www.goodluckbuy.com/nrf24l01-ism-2-4ghz-wireless-comunication-module-24l01-ptr6000.html
2.4 Ghz (says it can ship video … hmmm) - multi-point communication … hmmm
$5 - wow…
sweet, let us know how they
sweet, let us know how they work out! (I hope you don’t get burned with identical mac addresses)
Did you verify whether or
Did you verify whether or not the modules from goodluckbuy have unique MACs?
The units seem pretty robust
The distributer did not dicern the difference between “host” and “passive” modules when I purchased them. I ordered 6 and they randomly sent me 5 host modules and 1 passive. Now, I see that they make the distinction and are selling them seperately. Grrr… the passive ones are more useful for me… I’ll be ordering more passive units…
You can get all the details here
http://myrobotlab.org/node/118
I can check 2 host modules if they have different MACs, but I only have 1 passive unit.
