I got a pedal board (the Hammond XPK-130G) in July last year and have been using it with the Pianet sound on my Nord Electro 5D right from the start, just for my own enjoyment. Since the Sound on Sound article on Ernst Zacharias says that "Zacharias also mentioned building a monophonic pedal-tone generator which was designed as a bass accompaniment for a piano," I felt that recording tunes with the Hohner Pianet sound and organ bass pedals wouldn't be too far of a stretch of authenticity.
Just days after I recorded the first piece like this, I discovered via this catalogue that Hohner actually made a stand-alone bass pedal unit similar to the Hammond one that I have.
Here's the entry in the catalogue:
Here's my translation of the text:
Hohner - Universal-Pedal with SustainStand-Alone Bass Instrument13-note pedal with sustain (as with the Symphonic 707) with a control unit (power supply). With the S 707, the power supply is built into the instrument.1st knob from left: Pedal register 8' and 8' + 16'2nd knob from left: Adjustment for pedal decay time3rd knob from left: On switch and adjustment for loudspeakerThe control unit can be mounted either on or under the instrument.
As far as I can tell, there's not very much about the Universal-Pedal on the internet, but I did find a YouTube video about it (although the technical details are far beyond my comprehension):
Note that, based on what's shown in the video, the picture of the control unit in the Hohner catalogue is upside down.
I don't know the production dates of the Universal-Pedal, but since the Pianet N is in the same catalogue, their dates overlap to at least some degree, and it would have been entirely possible to use the two together.
Like Hohner's Universal-Pedal, the Hammond XPK-130G has built-in sounds, but for the two recordings I've done (one yet to be posted), I used the MIDI functionality to play the "B3 Bass" sound on my Nord Electro 5D. If I make any more recordings, though, I'm going to use one of the XPK's built-in sounds because that tone seems a bit closer to that of the Universal-Pedal.