More "bare iron" development: OsmoSDR, osmo-e1-xcvr and SIM bank

I'm currently quite excited to be doing more bare iron programming as well as actual electrical engineering work again.

There's actually not just one project I'm working on, but a variety of them:

  • OsmoSDR - an upcoming small form-factor, inexpensive USB SDR. Not big and expensive like USRP or real "professional" solutions, but also not as weak as the ultra-narrow-band funcube dongle. I wasn't involved in the hardware design, but have volunteered to take care of the firmware development for the Atmel SAM3U micro-controller inside.
  • osmo-e1-xcvr - a relatively simple circuit board containing the magnetics, LIU, clock generation and transceiver for E1/T1/J1 lines. The idea here is to have a solution for the analog part, as well as HDB3/B8ZS/AMI encoding, which can then be attached to any FPGA, CPLD or micro-controller development board. It exposes SPI for controlling the transceiver, and a synchronous serial bit-stream for Rx and Tx.
  • unnamed sim-bank project - here the goal is to find a cheap solution to attach a large number of SIM cards to either a PC or directly to Ethernet. This can be very useful for testing, where you host your sim cards in a centralized location and can borrow them to remote users/devices over TCP/IP. There are commercial devices available for this, but they are quite expensive (like 1700 USD for 32 card device) and intended to be used with some proprietary windows software (who wants that?!?).

In the latter two projects I'm also doing the component selection, schematics design and PCB layout. One project with KiCAD, the other in EAGLE, as I really want to get first-hand experience of the usability of Free vs. proprietary EDA tools. I'd love to also evaluate Altium Designer, but they are still windows-only, and that would just make life way too difficult for me.

The projects will be duly announced soon, and they are all intended to be Open Hardware designs with Free Software. We'll probably also make all of them available at, too.