Friday, November 26, 2010

Bluetooth Thermometer R3.0 - Up and Running

Happy Friday Everyone,

After another busy week at The OC it was time to kick back, relax, and do some hardware design. After several miserable lab periods spent debugging R2.0 hardware I discovered that for some reason the PIC16F628 was not willing to run off the 3.3V power supply on the board, even though the datasheet claims that supply voltages as low as 3.0V are fine.

Not wanting to waste any more time, I swapped the PIC16F628 out for the PIC12F675 used in the original design. It was such a substantial change that I ended up scrapping the old PCB file and starting from scratch, and after a quick three hours in Altium Designer I had my revised schematic and PCB layout.

Figure 1.0: A 3D Rendering of the New PCB

The design transferred perfectly to copper the first time, bringing the total fabrication time down to just over an hour. Right now I'm just waiting for the new Sure Bluetooth Module to arrive in the mail; in the mean time I have a few wires going from the PCB to a breadboard with the one lonely module I do have jammed into the side.

Figure 1.1: Completed PCB with Bluetooth Module on the Side

I spent a little more time hacking away at the firmware; unfortunately I won't be able to implement any of the configuration options I was hoping to due to the minute amount of memory in the PIC12F675.

That's all for now - With any luck I'll be able to post the firmware, schematics, gerbers, and PCB layout on my website. 

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