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Saturday, June 11, 2016

K40-S Middleman Board Interconnect


The Smoothie needs to be connected to the electro-mechanics of the K40. This includes:
  • X stepper (both phases)
  • Y stepper (both phases)
  • Optical endstops (Optical End stops)
    • Y endstop (open collector)
    • X endstop (open collector)
  • DC power distribution
The  K40-S BUILD INDEX with schematics


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Your donations help fund additional research, tools and parts that I will return to the community as information and how-to's. 


In operation fully tested and working fine :)


You can get the board here:

The middleman schematic and board layout is below:

The connections to the Smoothie are labeled outside the associated connector. 

Note: the pins on this connector are reversed from the other end due to the nature of the FFC connector and single sided cable, its complex to describe, hope this picture helps.

See: Post on Optical End stops

Middleman board and cable orientation

Assembly and connector orientation:


In search of a ribbon cable source

The ribbon cable that connects from the endstop daughter board evidentially is not very standard. I have not found a source of replacement.

The cable specs are:
Length: ?? haven't measured it yet.
Pitch: 1.25mm
# of conductors: 12
Type: FFC

You can find 1.25mm pitch cables but they are two many conductors and not long enough.

Some places I am looking:

Let me know if your find one .... +Don Kleinschnitz


Ribbon connector placement and orientation

The middleman in operation

The Middleman's wired into the system
Middleman mounted in electronics cabinet.

Middleman as an endstop test board

What do you do with an extra Middleman board?

Build an optical end stop tester .... of course !

Lately I have been tinkering with end stops more than anyone should and while looking in my Smoothie conversion parts bin it occurred to me that I could use my extra Middleman board and connector to make an endstop tester.

Done .....

Schematic is here with use instructions:

Package is here, nothing impressive. It uses 2x 2016 button batteries and holder. :

Video is here:

Note: if you don't have a Middleman board you can make one of these using a FPC connector whose pins are soldered to the battery, switches and LED's see the schematic.


Enjoy and comment especially if you see errors
Maker Don

1 comment:

  1. Standard issue Raspberry Pi camera ribbon cable appears to do the trick.