Plug-in XBee Adapter for the S2

Phil Pilgrim (PhiPi) · 2012-05-07 15:41

The S2's DB-9 serial connector provides battery power (Vin) to pin 8. This allows for the possibility of plug-in modules that receive their power from the S2. A natural use for this capability is an adapter for the XBee family of wireless interface modules, so I decided to make one. This was kind of a stealth project that I designed one day last week on a whim. The boards arrived today, and I'm happy to say that they work! Here's a photo:

attachment.php?attachmentid=92317&d=1336429990

attachment.php?attachmentid=92317&d=1336429990

Because the XBees run on 3.3V, and the XBee Pro requires up to 215 mA during transmit, it was impractical to step the battery voltage down with a linear regulator. So, in order to save wasted power and heat, I've included a switching regulator circuit on board the adapter. Also, since the S2 provides and requires RS232 (inverted) serial, it had to include transistor inverters. Other than that, it's a small, simple device that fits entirely within the S2's turning radius and doesn't cover up the LEDs or get in the way of the power switch or input button.

I have no idea yet about manufacturing or even whether there'd be any demand for such a device. Is this something that people might want?

-Phil

W9GFO · 2012-05-07 15:50

Absolutely!

mindrobots · 2012-05-07 15:55

YES!

S2 x 3
Roving Network WiFi??

W9GFO · 2012-05-07 15:59

Will it work on the blue Scribbler or other robots with the serial connector?

Phil Pilgrim (PhiPi) · 2012-05-07 16:23

It's specifically designed for the S2. IIRC, the blue Scribbler provides +5V on pin 9 of the DB-9, instead of Vbat on pin 8. It should work with any DCE device that provides 4.5 - 22V on pin 8, though.

-Phil

Ttailspin · 2012-05-07 16:23

Yes, the people will want this...:thumb::thumb:

The people will also want instruction and demonstration...
oh, and the people would really like schematics too.

Go! Phil Go!

-Tommy

sylvie369 · 2012-05-07 16:52

I want one. Oh yeah.

Martin_H · 2012-05-07 16:57

I think people will buy that. I just bought the Bluewolf 3.3V TTL to DB9 converter which is similar.

http://www.parallax.com/StoreSearchResults/tabid/768/txtSearch/bluewolf/List/0/SortField/4/ProductID/752/Default.aspx

The Bluewolf module is paired with their XBee host board, but it won't work with either Scribbler model. So if you could get it to work with a Boe-bot as well it would be great. I plan to pair the Bluewolf module with a Wixel and take a crack at wireless programming of the Boe-bot.

Phil Pilgrim (PhiPi) · 2012-05-07 19:14

Martin_H wrote:

So if you could get it to work with a Boe-bot as well it would be great.

The BASIC Stamp modules require a BREAK condition to program, which cannot be sent directly via the XBee modules, but has to be reconstructed at the receiving end by special logic which, apparently, the Flashfly supplies. So I'm definitely not targeting this as a BOE-Bot solution, especially since Parallax already has that covered. In fact, I don't even include DTR signaling, since it's not necessary for uploading Prop programs via LoadXB and the XBee.spin object: http://forums.parallax.com/showthread.php?127780-Upload-Prop-programs-via-XBee.

-Phil

Mike Green · 2012-05-07 20:24

I'd take one.

Mike Cook · 2012-12-14 17:27

I'm late to the party, but I would like one.

Phil Pilgrim (PhiPi) · 2012-12-14 17:55

'Glad to see the continued interest! There's a companion product that I need to do in conjunction with this one that will make it more useful, and that's a battery-powered remote control. I was thinking of including a pot-based joystick, a couple pushbuttons and a linear pot. If anyone has any other preferences, please let me know -- here would be okay, since it's still on-topic.

Thanks,
-Phil

W9GFO · 2012-12-14 18:02

If you need any joysticks with pushbuttons let me know. I have several hundred on hand. They are the same as the Parallax ones, except with a push button, kindly sourced by Ken.

Phil Pilgrim (PhiPi) · 2012-12-14 18:23

Thanks, Rich. I have a handful of those selfsame joysticks myself -- oddly enough, from the same source.

-Phil

RobotWorkshop · 2012-12-14 20:36

Phil Pilgrim (PhiPi) wrote: »

It's specifically designed for the S2. IIRC, the blue Scribbler provides +5V on pin 9 of the DB-9, instead of Vbat on pin 8. It should work with any DCE device that provides 4.5 - 22V on pin 8, though.

-Phil

Hello Phil,

Nice project! I think there is definitely interest in these. In regards to the power can't you just add a 3-pin SIP header and use a jumper to select which pin provides power? Either that or pads that could be solder bridged to select the voltage. You could put a tiny trace between the two as the default for the S2 which could be easily cut when you want the other power source.

Robert

TLC · 2012-12-15 09:32

You can add me to the list!

Todd

hyperritual · 2012-12-15 15:57

Me too; very interested.

Joshua

Whit · 2013-01-04 06:00

Don"t know how I missed this! Count me in the "want it" list Phil!

Gareth · 2013-05-20 07:38

Also for me ......how come this slipped me by......
I am now shoehorning the XBee inside the S2 (Yes inside ...the idea of plugging onto the RS232 thingy eluded me ..Duhh ).......

I am successfully using it as a Cable-Free link using the Tiny Logo OBJ shown in the forum post "Here"

I have reduced the XBee power setting to its lowest setting as i don't envisage out of site control (just to prolong operation).... i think the S2s Hacker port 5 volt is any-ways rated for 1.2 A max (correct me if i am wrong)

ratronic · 2013-05-21 12:55

Sorry I missed this thread - I have been trying to figure how to do something like this. I can also see other interfaces being built with your xbee one. Put me down for one!

Whit · 2013-06-07 19:13

Any word on this project Phil? Maybe a kit?

Phil Pilgrim (PhiPi) · 2013-06-07 19:37

Hey Whit,

Thanks for the continued interest -- and your patience! I was holding off because I wanted to pair it with a joystick-type remote controller. But I've come to the conclusion that there is a better way to go about that part. So the plan now is to proceed with the adapter by itself. I've got another loooong-awaited module going into production now (1500 boards made and a quote for the assembly). When that's out the door, I can revisit the XBee adapter.

BTW, because of all the SMD parts, it will probably come premade -- or possibly as a semi-kit, with only the through-hole parts to solder. The latter is a little harder, though, since testing is not as easily accomplished.

-Phil

Whit · 2013-06-10 06:42

I'll keep my eyes and ears open for the latest. Thanks for the update Phil!

WBA Consulting · 2013-10-26 23:06

Just caught wind of this as it was referenced in another thread. What's the latest?

ratronic · 2013-10-27 08:51

EDIT: Sorry Phil I still want one of these if you make it. So that I can communicate data to/from a program in my computer.

Phil Pilgrim (PhiPi) · 2013-10-27 09:10

WBA Consulting wrote:

What's the latest?

ratronic wrote:

Phil due to your other idea please scratch me off this list. Thanks

Much of the inpetus for the XBee plug-in was for remote control. But XBees are not the most economical way to achieve that, given that complete 2.4 GHz RC transceiver/receiver sets can be obtained for about $25 from HobbyKing. I had considered a similar external module to interface an RC receiver but then decided that it would be easier just to stuff one inside the S2 (my "other idea") and connect it to the hacker port. I think that pretty much covers remote control for the S2.

So that leaves wireless data exchange with the S2, which the XBee module can still handle. But I'm not sure how much interest remains for such an app.

-Phil

Mike Green · 2013-10-27 09:49

I'm still interested, but more in an xBee adapter that would support a WiFly module. I've tried (with no success) to use Parallax's 5V xBee adapter with the hacker port (works one way, but not the other), so I'm still looking for a solution. A WiFly module would let me use my iPhone as a controller. Advice / suggestions would be appreciated.

Phil Pilgrim (PhiPi) · 2013-10-27 10:06

Mike,

Email me your postal address, and I'll send you one of the plug-ins to try out with your WiFly module.

-Phil

WBA Consulting · 2013-10-27 15:21

Thanks for the update Phil. I see your point, however this style of solution fits another idea I am working on for my daughter's S2 and that was where my interest came from. My mods in progress will all be externally attached.

erco · 2013-10-27 16:32

I'm REALLY late to this party. A year and a half. Dunno how I missed it. Fabulous concept & execution as always, PhiPi!

Crazyrabbit · 2013-10-27 16:32

Looks interesting. Will it also work on RPM board. Put me down for one. I also have a new Scribbler 2.

Plug-in XBee Adapter for the S2

Comments