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This is a project tageted on ZigBee communication over 802.15.4. It is currently using a Atmel AVR CPU (ATmega88) and a Freescale MC1319x (MC13191, MC13192 or MC13193) for communication on the 2.4GHz free frequency.

We are trying to make it as cheap as possble. In qty 9+ you can get away with about 150SEK ($20) per unit. Plus work :)

All hardware drawings and source code is free for all and released under GNU General Public License 2.

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The ZigBee protocol stack is not yet implemented. We have a basic protocol stack working with which you can send/receive data packets. The data throughput on the MC1319x is about 250kbit half duplex, max packet size is 125 bytes, hardware CRC, small overhead.

Source code for raw packet communication, developed with WinAVR-20060125.

The communication distance with the PCB antenna is about 15 meters in free air without obstacles.

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We have used the freeware version of the EAGLE PCB Layout Editor from Cadsoft.

Our PCB is a dual layer 8 mil design so if you are going to manufacture the PCB by yourself you ought to have a pretty nice lab! :) We order our PCBs from Olimex and their work is ok quality!

There are two versions of the PCBs.

• The SerBee is a bit larger with a RS232 driver and a powerful voltage reg. The board measures 53*33mm so you can fit 9 boards in a standard 16*10cm panel.
  
  
• The MiniBee lacks those features but is a bit smaller in return. This board measures 53*24mm so you can fit 12 boards in a standard 16*10cm panel.
  
  

The PCBs has pads for most of the IO pins on the AVR which makes it ideal for remote control of...stuff...

Soldering the board is (almost) easy. You can do this by yourself with some solder paste and a regular oven. We've tried it and got the know-how from this guy. A note to all europeans, the temperatures in that article is in fahrenheit. Use google to convert to celsius. These guys also have great tutorials. The solder paste that we used started melting at about 160 deg C. A toaster oven or some other small oven might be a bit better since they most likely will reach wanted temperatures faster due to the smaller air volume. Take a look here for a step by step illustrated guide on how to solder one of these!

Freescales MC13192

We built these cards by applying solder paste pad for pad at first, it is tedious and time consuming work. If you know you are going to do a couple of boards a nice thing to have is a solder paste stencil, it saves you time and improves quality alot. We order ours from www.pololu.com, they have a special site for stencils at www.SMTstencil.com. If you go for stencils you might also want to build a simple vacuum table to hold the stencil in place while applying solder paste.

Don't place the complete PCB on a surface in the oven, there should be air underneath the PCB, that way it will heat faster. Don't open the oven as soon as you see that the solder paste has melted, it might take some extra time for the paste underneath the MC1319x to melt. In our case I let the oven reach at least 180 deg C. And maybe it is a good idea to not make use of the same oven that you cook food in, the ingredients in solder paste are NOT good for your health!

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As usual all things that can (and can not) go wrong, sometimes do. This is a fairly complex project and it might be a bit tricky to get the soldering right on the first try. We wont take any responsibilities for any damage you manage to do :)

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SerBee	MiniBee
Eagle schematics Eagle board Bill of material (BOM) for Rev A01	Eagle schematics Eagle board Bill of material (BOM) for Rev A01

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SerBee PCB with components soldered.	PCB top
PCB bottom	Eagle board.

Eagle schematic.


MiniBee


The new MiniBee

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