I'm trying to squeeze the most out of this design. I've had a few feature requests and a lot of them were tap-tempo. Harmony-Central user crxsh had a good idea about making the soft-stomp, the one used for recording of shapes, multi-function. Specifically, being able to toggle it between record, tap-tempo and bank select.
I'm gonna see how feasable this is. It won't be ready for the next few batches as I still have PCBs to use up. Testing and optimizations also take time. But hopefully I'll get those to work. A three-way toggle switch could be placed on the side of the box next to the soft-stomp with a label describing the three states.
Another issue the Hollow Earth seems to have is that expression-out doesn't work with every pedal with expression-in, only some of them! I never intended it to be a main feature, just as a fun extra, but it seems more people want to use it than I had previously thought. I'll try and put some effort into increasing the compatibility of exp-out.
For the geeks, an expression pedal is basically a potentiometer. Potentiometers have three lugs, one for the minimum range, the max range, and the wiper. The way the Hollow Earth outputs expression control is by controlling an LED-LDR combo (an electrically-controlled pot), which due to its nature is the equivalent of an only 2-lug pot. While this works with many pedals with an expression-in jack, it doesn't work with those expecting 3-full lugs. So far, this includes the Eventide Timefactor and EHX HOG. I'll do my best to fix this in a later revision.