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Rift
10-14-2008, 10:49 AM
So the Xbee definitely seems to be the way to go the price actually comes out to less then the bluetooth equivalent and if i ever need i get the added range.

My last question would be will i be able to use the Lynxmotion SEQ and RIOS software with this. I know they connect through a COM port but will i be able to mimic something equivalent with this setup?

Looking forward to your tutorial!

Rift

lnxfergy
10-14-2008, 11:30 AM
Once you tell the XBEE modules who to talk to, they just act like a normal serial port. From the computer's perspective, it is just like having the serial cable connected instead of the two radio modules talking...

-Fergs

Adrenalynn
10-14-2008, 12:43 PM
I concur with Fergs. It's just a COM port on the computer, and an "invisible serial cable" once it's all properly configured and the "glue hardware" built around it.

Rift
10-14-2008, 01:08 PM
What do ya mean by "glue hardware"?

Looks like this will be the way I go then. Other then the two Xbees and the USB Explorer what other parts do i need to make this functional?

Rift

Adrenalynn
10-14-2008, 01:15 PM
You need to power it with 3.3v and you need to match the 3.3v TTL to the 5vTTL on the SSC32.

At the simplest, a handfull of resistors doing a couple voltage dividers. Tyberius is going to a voltage divider on the TX and a regulator for power.

I'm using Octal drivers on TX/RX and an LDO regulator for power - but I'm anally retentive. ;)

Rift
10-14-2008, 01:28 PM
I see. Makes sense to me in theory but ill probably have some questions regarding the execution because i haven't had a whole lot of exposure to putting together electronics. Its something that iv wanted to learn for some time now.

For starters what kind of regulators will i need? I'm putting together a list so i can just order everything in one shot providing Trossen has all the parts i would need.

Rift

DresnerRobotics
10-14-2008, 01:30 PM
I'll have a comprehensive tutorial, with schematics, pictures, and a parts list up here in the next day :)

Rift
10-14-2008, 01:40 PM
That's awesome! I'm looking forward to it and thanks again to everyone for the help. Quite an awesome community going on here glad to be a part of it. :D

Rift

Rift
11-29-2008, 10:49 PM
Sooo I have this all hooked up according to a diagram Tyberius sent me and I'm pretty sure I did not put anything together wrong. But I can't get the Xbee's to connect.

Whenever I open the SEQ software and set the com port to the one assigned to the USB serial device all it does is say waiting, as it attempts to connect.

Are there any special settings that have to be done to get these to work with the SSC-32?


Rift

Adrenalynn
11-29-2008, 11:32 PM
Did you configure the XBee's first?

Rift
11-29-2008, 11:41 PM
Mmmm this might be the problem what has to be configured for them? This is my first time using them.


Rift

Adrenalynn
11-29-2008, 11:50 PM
http://hades.mech.northwestern.edu/wiki/index.php/XBee_radio_communication_between_PICs#Setting_up_Y our_XBee_Network

Rift
11-30-2008, 01:01 AM
I got the X-CTU software that they recommend using, and have found all the options that the wiki mentions but when i try to write to the modem it just refuses and say's it cant find it.

Rift


EDIT: Alright I have managed to write to them using the guidelines in the wiki but still no lick with SEQ

Adrenalynn
11-30-2008, 02:45 AM
>>but still no lick with SEQ

Well, try not licking SEQ - that's not really what it's designed for, and definitely unsanitary. :tongue:

Have you tried just using a terminal program? No reason to add a bunch of complication all at once. Just try to send a single command to the SSC32 and get that working first...

Rift
11-30-2008, 11:18 AM
LOL mmm yeah licking SEQ might not be the best of ideas haha

Just tried using Lynxterm it seems to be able to connect through the com port and when I try to send a signal to the servos a light blinks on the Xbee connected to my computer but nothing else happens.


Rift

Resilient
12-11-2008, 04:57 PM
How has it been going Rift?

I am thinking I am going to be doing something like this soon and was wondering how it was working out for you.

DresnerRobotics
12-11-2008, 05:43 PM
I never had time to get my tutorial made up, been too busy. Here's the schematic for what I did to interface mine:

http://www.trossenrobotics.com/images/Xbee-SSC32-Interface.JPG

Adrenalynn
12-13-2008, 09:00 PM
I'm working on a really clean interface from the XBee to the SSC32 on one side, and the Arduino to the XBee on the other side (smaller than the backpack)

Tyberius found this really cool logic level convertor board at SparkFun (http://www.sparkfun.com/commerce/product_info.php?products_id=8745), and I'm finally getting around to building out around it. I'll update here with what I find. I'm not fond of Tybs voltage divider above for various and sundry reasons... Also, there's no filtering what-so-ever on his regulator - I'm not sure I'd do that with such a touchy component...

Soldering headers on that board probably isn't for the newbie solderer, though... And you probably want a good iron.
912
913
914

I also tossed together a regulator to power it based on the LM317 Adjustable Regulator. It has a large buffer cap and is filtered pretty well, with reverse protection. If it helps, I can toss up instructions. The XBee is pretty picky about its supply voltage range. 2.8-3.4v, I believe. I tried to hit it pretty much in the center with nothing but parts-on-hand...

I'm just going to solder mine up on perf-board for this project, but here it is proto'd on breadboard. I'll solder it up tonight probably.:

915
916

Rudolph
12-13-2008, 10:15 PM
Mmmmmm, pi. I have to ask if you did that on purpose.

DresnerRobotics
12-13-2008, 10:32 PM
I like my simple and dirty way of doing it :P

Adrenalynn
12-13-2008, 10:39 PM
Mmmmmm, pi. I have to ask if you did that on purpose.

OMG! No. You'd have thought I would have noticed that! Wow. I'm going to have to give you +Rep. Sorry. No other option!


Tybs - no disrespect, and you and I chatted about it. I just can't get behind unfiltered power...

Rudolph
12-13-2008, 10:46 PM
ROFL

I almost didn't even ask. The little bit I know of you so far I just figured that's the kind of thing you'd do on purpose. Like I do... hehehe

gdubb2
12-13-2008, 11:37 PM
I tried both ways, and wound up using the same method as Tyberius with a slight difference of resistor values, and an LED from pin 6 on the XBee in series with a 470 Ohm Res. to ground for a signal varification.

Adrenalynn
12-13-2008, 11:37 PM
I wish I had... Seriously...

I backed into the closest thing I could find on hand. I had a 150 Ohm, 180Ohm, and 100Ohm resistors easily handy. A 180 + 100 would give me about 3.55v, so I figured a 150 Ohm would have to be about right. I knew a 140 Ohm would yield 3v.

It all worked fine on the breadboard. Now I pulled it all off and soldered it up on a perf-board, and it doesn't work. Nothing pops, regulator doesn't get hot, no output. I'm putting a solid 10v into it, and I can see that on my input end. Reading adjust or looking for shorts in-circuit is nigh-on impossible because of all those caps. I can see 'em charge up and discharge when I put my meter on them. Grrr. Getting perfs apart sucks too. I might just start again... ;)

Adrenalynn
12-13-2008, 11:39 PM
I tried both ways, and wound up using the same method as Tyberius with a slight difference of resistor values, and an LED from pin 6 on the XBee in series with a 470 Ohm Res. to ground for a signal varification.

Which "both ways" ? With the Sparkfun level match and with a couple resistors? Or are you saying you tried the 3.3v regulator with filtering and without filtering, and decided that a power supply is superior without filtering?

Sorry - I'm cornfused. :o

gdubb2
12-13-2008, 11:47 PM
First I tried the Sparkfun level converter. I had some issues with it, but it was probably me. Then I downloaded the 5 V. to 3.3 V interface schematic from Sparkfun, which came from Kronosrobotics. It's worked great for me, so I stayed with it. Just didn't feel like playing with the cute little things from Sparkfun any more. Although I have a few on hand if I change my mind.

Adrenalynn
12-13-2008, 11:52 PM
Good to know! What kind of issues were you having with it? I haven't gotten any further than building it out yet, since my %#$%#$^# power supply board isn't putting out any power now that it's pretty. Should have left it ugly but working. ;)

Resilient
12-14-2008, 12:46 AM
OMG! No. You'd have thought I would have noticed that! Wow. I'm going to have to give you +Rep. Sorry. No other option!


Tybs - no disrespect, and you and I chatted about it. I just can't get behind unfiltered power...

When you talk about filtered vs. unfiltered, do you just mean putting capacitors on the voltage regulator to help even it out?

Adrenalynn
12-14-2008, 12:53 AM
Sorta. "Even it out" would be something of a misnomer. Yes - you want to catch transients (spikes and sags), but you also want to get rid of any ripple, catch any low or high frequency noise, etc.

DresnerRobotics
12-14-2008, 01:56 AM
I'll say the following with a disclaimer (And Adrenalynn will still 'tisk' at me I know it):

"If you do the following and burn up your hardware, I hold no responsibility. Proceed at your own risk."

Now that said, I've actually been running a 2nd SSC-32 without a level converter on the TTL at all. The Xbee appears to be 5v tolerant on TTL, though I'm still using a 3.3v reg for input voltage as the Xbee is NOT in any way 5v tolerant for power. I tried this out after finding a thread on AVR freaks where a bunch of people were testing the Xbee's 5v TTL tolerance with success.

That said- I'd only do this for experimentations or for a quick and dirty test circuit. For any important circuit (such as your control solution for your Mech Warfare bot), I'd recommend spending the money to setup a level convertor, just to play it safe.

Adrenalynn
12-14-2008, 02:35 AM
Tisk...

Good way to shorten hardware life.

Adrenalynn
12-14-2008, 05:12 AM
Bwahaha - finally... Turned out that when I pulled one of the disc caps out of the bread board, I'd cracked the ceramic and it was enough for it not to make connection. Tough one to find...

The blue LED is supply power, and the orange LED is output on the PI Line. ;)

gdubb2
12-14-2008, 01:42 PM
Adren, I was having problems getting the signals through. I think it was probably my breadboarding or construction. No problem with the other scheme though. I am using the same resistor values as Tyb, except my resistor on the Tx line (pin2) is 100 Ohms. My board seems to like it OK.

I realize this thread is about the SSC32, and I am using a Hitec board. But the levels are still 5 Vdc and 3.3 Vdc. So I felt comfortable with my comments. Also the LED on Pin6 is handy as it shows when the radios are connected. I also used an adjustable regulator. A couple of resistors and I have whatever voltage I desire. I run my bot everyday, and it's a happy camper with this lashup.

Resilient
12-15-2008, 03:02 AM
So whats the difference between the Sparkfun level converter and just a voltage regulator like Tyberius' setup?

Adrenalynn
12-15-2008, 03:08 AM
Tybs setup isn't "just a voltage regulator" - there's a resistor voltage divider in there too. The Sparkfun solution still requires a 3.3v-ish regulated power source.

The difference between the level converter and Tyb's divider is the addition of a transistor. It's an ok solution but far from ideal. I'll probably end-up designing something more robust shortly, although I am pretty happy with the stability clean power offers. I've transfered more than 50MB of data with only two dropped packets.

Rift
12-15-2008, 10:27 AM
I did eventually get my setup to work. There was actually never anything wrong with the XBee's and no initial configuration was actually necessary. What ended up being the problem is that my 3.3v reg was a different model and the pin outs ended up being different ground and out were switch and the Xbee wasn't getting any power.

The setup was super simple a little heatshrink and some liquid tape to make everything nice and it works perfect!


Adrenalynn I'm curious as I'm a bit of an electronics noob and still in the process of wrapping my head around everything, you mentioned you filter your power? What exactly do you mean by that and what advantages does that bring?

Within the circuit Tyb's posted is there something else you would add?

For now i haven't had any problems and the setup works and was super easy to put together, but I'm always up for improvement and learning new ways to do things.


Rift

gdubb2
12-15-2008, 11:52 AM
Rift.. Quick and dirty filter is to put a .1 Uf capacitor between Vin and ground and a 1 Uf cap between Vout and ground on the voltage regulator. I didn't filter the reg on my setup, mostly because it's really close coupled and the battery voltage is solid. Also put filter capacitors on all motors leads. Motors generate noise on the lines.

jes1510
12-15-2008, 12:11 PM
Rift.. Quick and dirty filter is to put a .1 Uf capacitor between Vin and ground and a 1 Uf cap between Vout and ground on the voltage regulator. I didn't filter the reg on my setup, mostly because it's really close coupled and the battery voltage is solid. Also put filter capacitors on all motors leads. Motors generate noise on the lines.


I would also add that if there is a length of wire between the power source and the device then putting a 0.1u cap from the Vcc lline to ground is a common practice. The caps sizes may change depending on your current requirements. If you are drawing a lot of current from the device then a bigger cap on the Vout may help.

Rift
12-15-2008, 12:32 PM
Forgive my total noobness by cap you mean capacitor right? How are the values read? 0.1u would mean what? I'm looking up info on it and getting a bunch of values but not sure what to make of any of them.

Rift

Rudolph
12-15-2008, 12:52 PM
A .1uF capacitor is 1/10th of a microfarad. It's also 100 nanofarad.

I refer to this (http://www.justradios.com/uFnFpF.html) quite often :)

Adrenalynn
12-15-2008, 12:54 PM
Also any wires that are going to run past sources of noise. We don't have any of those on robots, though. Nothing like, oh, radio transmitters, electric motors, metal gears, metal chains, metal cables, any place metal moves against metal, anything that generates an electromagnetic field... Oh wait - that's *every stinking thing on a robot* ;)

Yeah, filtering is kinda important. ;)

Capacitors are measured in Farads. uF = micro Farad. pF= Pico Farad. Always always always get capacitors that are rated for more voltage than your circuit can possibly put through them. Of course, I broke that rule to some extent - I didn't have a big 50v handy, so I put a 35v 22,000uF on my input - but the regulator can take up to 37v as input. [shrug] It's built for a specific project and won't ever see more than 11v, so it's fine. ;)

gdubb2
12-15-2008, 12:58 PM
Yes.. cap in capacitor, they are measured in micro farads or pico farads. The U is a crappy imitation of the symbol for micro. The .1 Uf is .1 micro farads. Also some are polarized some are not. Ceramic capacitors are not polarized, Electrolytic and mylar usually are. If you end up with capacitors with a +++ or -- symbols on them, they are polarized and should be connected with the + to the Vin and Vout with the negative - side connected to ground.

Even more confusing, some capacitors are color coded, and some use designations like 104. The 104 would be measured in Pico farads. 104 would be 100000 pico farads or .1 micro farads. Pico or for us acients micro micro is really small values. The 4 on 104 is 4 more zeros added on then back up 6 places to get to micro.

Hope I didn't confuse you even more with this. Here's a link to some other data..

http://www.play-hookey.com/dc_theory/capacitor_values.html

Rift
12-15-2008, 01:11 PM
Nope I didn't get confused to bad haha I'm a little confused but I'm going to read up the links you guys posted in hopes of getting a better idea. Quite a load of information tho!


Rift