EuroNova:

The EuroNova is an add-on board for the NovaDrone that allows easy and safe interfacing between your NovaDrone and a eurorack style modular synthesiser. It can also be used as a signal splitter for sending individual signals (such as the three main oscillators) to a mixing board or other signal processing hardware.

The EuroNova is completely modular which means each of the 4 jacks can be configured to send and receive whatever signals best suit your needs.
Each jack has 2 I/O connectors that plug into the breadboard through 1k current limiting resistors. This helps protect your NovaDrone but also acts as a passive mixer/splitter for each jack, meaning that two LFOs (for instance) can be mixed to one jack giving a more complex wave form to use for modulation in your system.

!!IMPORTANT!!

The jacks on the board are not grounded. Ground is basically the negative half of your power supply and is essentially zero volts. It gives the circuits a common reference point form which to measure the amplitudes of various signals.
The important thing is that the ground from your modular synth must be connected to the ground of your NovaDrone. This can be done a few different ways.
1. Connect the sleeve of the EuroNova I/O jacks to the ground of the NovaDrone. The jacks are all connected to the bottom power rails of the adventure board when its plugged in. Either of these rails can be grounded by connecting a wire from the rail up to one of the pins at the bottom of the ND board labeled β€œGND”. You will need to do some soldering for this approach.

2. Plug the NovaDrone and your Eurorack system into the same mixer and/or amplifier. Or plug the ND into a mixer within your eurosystem (BUT keep in mind that the signal levels from eurorack are much hotter than the ND! ). When the eurorack and ND are plugged into the same mixer/amplifier the ground of each will be connected.