Kenmore 158: LED Strip and Sensor Cable

The shaft position and motor RPM sensors require +5 VDC, the LED strip lights run on +12 VDC, and the yet-to-be-built needle lights in the endcap probably need an entirely different supply. After a bit of doodling, all that, plus a power button conductor, fits into nine conductors:

  1. K – +5 VDC for sensors
  2. Bn – common for sensors
  3. R – RPM sensor output
  4. O – Shaft position sensor output
  5. Y – Power button
  6. G – +12 VDC for LED strips
  7. Bl – common for strips
  8. V – + supply for needle lights
  9. W – common for lights

That’s fortunate, as I have a box of pre-built RS-232 cables. The nine color-coded 24 AWG (more or less) conductors seem a bit scanty for LED strip light currents, but they’ll suffice for now.

Everything terminates in a hideous shrub down by the motor pulley, with cable ties holding the wires away from the action:

LED Strips and Sensor - cable terminations
LED Strips and Sensor – cable terminations

Unlike the PS/2 connector for the foot pedal, mounting the DB9 “serial” connector required some bashing:

LED and Sensor DB9 - mounting
LED and Sensor DB9 – mounting

A pair of 4-40 washers, filed to fit inside the chassis cutout and away from the shell, keep the connector from rotating / sliding; the dimensions aren’t conducive to a 3D printed widget. The flat metal strips hold the connector in place, with the mounting screws threaded into 4-40 nuts behind the connector.

The top row of pins goes to a header (a bit fuzzy, near the bottom of the image) on the Low Voltage Interface board, where the sensor inputs go directly to the Arduino Pro Mini and the power connections to the ATX connector:

Low Voltage Interface Board - top view
Low Voltage Interface Board – top view

The LED power connections on the bottom row go to pins on an ATX wiring harness that used to send juice to the various disk drives.

I’m not real happy with that lashup, but … more pondering is in order. I suspect I’ll need a few more conductors for other things on the sewing machine, so a larger cable may terminate at a DB25 connector in the cutout just above this one.

8 thoughts on “Kenmore 158: LED Strip and Sensor Cable

  1. conductors seem a bit scanty

    Some years ago, a college friend was lamenting about his house. Seems the prior owner worked for Ma Bell, and the semi-finished basement was powered with lots of telephone cable. Enough in parallel to avoid a fire, but yikes!

    1. powered with lots of telephone cable

      I’m certain the insulation isn’t up to line voltage specs: as long as everything stays clean & dry & undamaged, it’ll be all good…

  2. Somewhere around here I have gcode for DB9 and DB25 cutouts: a nice aluminum plate would do well between that DB9 and the surrounding cutout. I’ll see if I can find it and email it.

    1. Or 303. I’m finding that if you’re careful with RPM and feed, the Sherline does a fine job of stainless as long as it has reasonable machinability.

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