This is the class-wide blog for asking questions and sharing ideas.  Click on "New post" to start a new thread, or click on "Comment" within a posting page to discuss.


posted Mar 3, 2011, 6:27 PM by Liang Wang   [ updated Mar 4, 2011, 2:53 PM ]

Hey guys,

So the packet format I would like you guys to follow is is similar to the Xbee teams.
Byte 0 - ID type (0 for RFID, 1 for Magstripe, 2 for Library code)
Byte 1 -GROUP ID( may just be like 0-9 for groups)
Byte 2-17 - PAYLOAD
Byte 18-29 - DATE follow this format MMDDYYHHMMSS so 030311172555 which is 3/3/11 5:25:55

If your scanner scans less than 14 characters, such as 10 for RFID, fill the rest with 0's all the way up to 16 bytes

If you plan on using encryption, team Latitude is using Xtea Encryption. Its quite easy to use.

For your Group ID Use the teams section on the left side for your group ID so

1 - ATeam
2 - Team Awesome

and so forth,


posted Feb 25, 2011, 3:18 PM by Liang Wang   [ updated Mar 4, 2011, 2:53 PM ]

Hey guys,

So the packet format I would like you guys to follow is
Byte 0 - ID type (0 for RFID, 1 for Magstripe, 2 for Library code)
Byte 1 -GROUP ID( may just be like 0-9 for groups)
Byte 2-15 - PAYLOAD

If your scanner scans less than 14 characters, such as 10 for RFID, fill the rest of them with 0's


BTW If you guys can support it, try to send a time stamp along with the payload. Something in the format of HHMM and if needed add SS as well. So the entire packet you guys are going to send should be about 22 characters long.

Also tell me if you guys plan on doing encryption of some sort.

YO! Team TBD

posted Feb 10, 2011, 9:59 AM by Paul McDonald

I finished getting the connector back on your little battery charger. I'm planning on going to the Sustainable Energy Semminar thing toninght (thursday the 10th) that was postponed from Tuesday. I think its at 7:30, in that one room upstairs, across from the MDA. I'll be checking my email at various intervals throughout the day. Catch ya later.

Good places for components (like jumpers & connectors)

posted Jan 23, 2011, 9:23 PM by Paul McDonald

Jk Electronics

6395 Westminster Boulevard
Westminster, CA 92683
(714) 890-4001

All Electronics | Electronic and Electro-Mechanical Parts and ... - Cached - Similar

If you go in person, do not be intimidated by the employees. Some will ask you things just to confuse you. Be polite, and be ready to explain what you need in different ways. Both these places have the lowest prices around and selections that you can browse. There is also a parts counter, where they keep sensitive and fragile components.

XBee clarification

posted Jan 23, 2011, 7:24 PM by Alex Chu

Hi all,
   I just wanted to clarify which version XBee's all the groups are working with. We as the gateway team have the series 2.5 one. I was wondering if anyone has the 1.0 version? Thanks.

No meeting Mon. 1/17/11 but please sign up for team appointment

posted Jan 12, 2011, 10:16 AM by Pai Chou

As announced, there will be no meeting Monday night 1/17/2011 (Martin Luther King Jr.'s birthday)
but please do sign up on EEE for your team appointment to talk to Prof. Chou in his office (EH 3219)
to review your team's progress.

Question to Scanner Teams

posted Nov 21, 2010, 3:43 PM by Liang Wang

Hey guys,

This is the gateway team and I was wondering how you guys want to format data transfer between you guys and us.

Do you want to push data or have us poll?

Would you guys like some type of handshaking protocol?

And would you guys like to have some sort of data integrity checking so maybe after we receive the data we send what we got back to you guys to make sure that the data we received is correct?

Also would you guys like to standardize what is sent so our send/receive functions look similar?


Parallax Reader is Super Easy & Robust

posted Nov 14, 2010, 6:14 PM by Paul McDonald

The reader rejects two tags by waiting until only one is in range. 10 data bytes seem to be ASCI characters, but I only had the two tags...
Power consumption is low when a tag is in range at the moment the reader is enabled because the read time is typically less than 0.5 seconds. Haven't measured inrush current yet.

Check out A Team's page for pictures of our test interface and SAMPLE TEST code that runs on an Atmega328P (and probably 168 too).

Scanners -> Gateway

posted Nov 8, 2010, 10:55 PM by Alex Chu

Hi all,
   this is the gateway team and it has recently been brought to my attention that we should ALL agree on one type of file format and encryption in terms of the scanners transfer to the gateway, so I would like to clarify that.
First and foremost, I urge all scanner teams to fill out the task matrix or leave a comment here about which wireless interface they plan on using to connect to the gateway so that we can try to find a module to attach to our board or define some protocols to handle your specific connection (if it is different from the others). From what I've seen in the task matrix and what I've heard so far, Zigbee seems to be the favorite. I'm not sure if there's other ones out there. PLEASE let us know so that we can try to accomodate your connection.
The second item is the format of the file. I know that we, as the gateway team, were suppose to contact Bob Cassidy about the database system and how it all works but it just kept slipping my mind. I believe some other team(s) (software only team?) has already contacted him and is already working with him in some detail. Could someone please give me his email, we can meet with whichever team that's working with him to go over details about the database, or can the team working with the database send one of us an email (mine is with the important information about the database? We will use the information from the database to determine what will be needed in the files of the data that the scanners will send (i.e. name, id, time, date, etc.) and in which order they should appear.
The last and final item is the encryption and format of the file. Can the scanners come to a consensus on which method they want to encrypt it in? I believe that using one method is the best since we don't have to cover multiple algorithms. Ideally we, the gateway team, would want the MD5 encryption because I believe that's the only way we can upload data to the database. As for the file format, I'm not sure which one is best for the scanners (maybe someone has a specific file format that'll save space for the scanners?). We were just thinking that a simple encrypted text file will do but I'm not really sure what the options are either. As long as a consensus is reached for both items, it'd make things simpler for us.
Thank you all for reading this long message.
- Alex Chu

Wireless & RFID consensus?

posted Nov 4, 2010, 10:30 AM by Paul McDonald   [ updated Nov 7, 2010, 4:15 PM ]

Is the consensus on ZigBee for the wireless scanner-gateway link?
RFID looks like the Parallax reader or the ID-12 from Innovations.
If enough groups choose this reader, perhaps we should look into volume discounts. Some suppliers will give us price breaks for 5,10,20,50, and 100 units. Who knows, maybe they'll even give us student discounts too...

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