Thursday, July 28, 2011

New panStamp PCB taking shape

We've got to a point where we need to make new boards and start beta-testing the panStamp concept. New boards have to solve the only issue detected so far, that's the intermittent problem when programming the panStamps from the Arduino IDE via USB. Apart from that, there are some technical improvements that will bring us new possibilities:
  • New boards are 24-DIP (0.6 inches) instead of 28-DIP.
  • SPI pins appear in a supplementary row, still accessible from the panStamp. This action has let us switch to the mentioned 24-DIP package.
  • Resonator footprint added. XTAL1 (PB6) and XTAL2 (PB7) pins are then removed.
  • All Atmega's IO pins are now available except INT0 (PD2) and the CC1101 chip select pin (PB2) that are exclusively dedicated to the communications with the RF front-end.
  • The Atmega328P will have a 32-MLF package instead of the 32-TQFP. We save a lot of space on the board doing this.
  • New boards have four layers instead of two, improving performance and allowing reasonable microstrip widths.
  • Passive components are now SM0402 packages instead of SM0603. SM0402 is the recommended package for any RF device emitting near the 1-GHz band.
  • New SMA connector footprint added into the board. We'll then have two possibilities: wire stub antenna for the cheapest designs and whip antenna for those special nodes needing greater communication ranges.
Besides working in a new hardware version of the panStamp, I'm also designing some specific mother boards, some of them being of great importance for the project:
  • USB board for programming panStamps and interfacing PC-based applications. The whole USB board and panStamp will fit into a conventional USB-stick enclosure.
  • New solar-harvester board for indoor applications. The NCP1400 approach will be abandoned and will surely use a MAX1722 instead, with lower quiescent current. For the solar part, we'll switch to a silicone amorphous panel, with greater sensibility under poor light conditions. On the accumulator side, different options will be available: NiMh AAA battery or super-capacitor.
And some other boards for internal evaluation. We'd see later whether these boards would see the light commercially or not. This will surely depend on the practical results and degree of interest from the community:
  • RGB-Strip controller.
  • Energy meter to be used with external current transformer clamps.
If everything goes as expected, new boards should be ready at the end of September. Those having transmitted their interest in participating in the beta-tests will be then contacted. Thanks everyone for your interest in the panStamp project!!


  1. Lgreat to see this moving along. What size are the new boards i.e. 24 dip by what?

  2. Thanks Bill. Size is 1.2"x0.7" approx.