What books/blogs/podcasts etc... discuss patterns and best practices for designing software systems that interact with custom hardware and robotics? I am particularly interested in any books that would discuss strategies for writing a program that has to orchestrate and coordinate actions between several different custom hardware and robotics systems.
I'm not sure of any particular blog or podcast based resources for this type of material.
However, it sounds like what you are doing would be a perfect fit for something like ROS (Robotics Operating System), an open-source robotics framework with a heavy emphasis on software engineering ideas. While it's not a book or blog, the framework along with the associated community is a great way to learn about the hardware/software interaction necessary for robotics systems.
You can find the website at ros.org