APC UPS NMC from a Pi

Adding a Raspberry Pi running NUT to an APC UPS with a "SmartSlot".

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Topend APC UPS' are capable of hosting a Network Management Card. These slot into the back of the UPS in a "SmartSlot".
Unfortunately, these are quite pricey.

I'm going to attempt to create a SmartSlot tray to host a Raspberry Pi 1 that can be inserted into the SmartSlot and provide management of the UPS via NUT.

I have an APC Smart-UPS 1500 (Model number SMT1500i)

So far, I've configured NUT on a Raspberry Pi 1 and connected via the USB port on the back of the UPS.

While this gives me the functionality I want, monitoring the UPS, it doesn't look very tidy and it requires an external 5v power supply.

Inside the SmartSlot is an edge connector that I believe provides the following pins:

  1. +12v
  2. GND
  3. +24v
  4. GND
  5. (unsure, possibly battery voltage output?)
  6. +5V
  7. (unsure *)
  8. (unsure *)
  9. Serial TX
  10. (unsure)
  11. RX enable?
  12. Serial RX
  13. Power on (trigger low)
  14. Power off (trigger low)

* I think these are for the environmental monitoring NMCs.

I'd like to use the internal connector to provide the GND, +5 and Serial RX/TX to the Raspberry Pi, this making the entire solution internal.

I'm hoping that the Serial protocol present on the Edge Connector is the same as used on the Serial port on the back of the UPS.

Measuring the SmartSlot dimensions shows that the Pi will fit inside with a low profile SD card adapter.

Next steps are to design a tray to hold the Pi and a small PCB with an edge connector.


The Tray inserted all the way into the SmartSlot

JPEG Image - 3.24 MB - 05/13/2020 at 05:47



The Raspberry Pi1 in the Tray

JPEG Image - 3.25 MB - 05/13/2020 at 05:47



The SmartSlot

JPEG Image - 3.72 MB - 05/13/2020 at 05:47



Design for the Tray that fits a Raspberry Pi 1 into a SmartSlot.

Standard Tesselated Geometry - 46.96 kB - 05/12/2020 at 05:54



Design for the Tray that fits a Raspberry Pi 1 into a SmartSlot. You'll need to adjust the rear panel cutouts for other Pi models. STEP file provided to allow this.

step - 216.94 kB - 05/12/2020 at 05:41


  • 3D Printing the Tray

    daffy05/08/2020 at 09:12 0 comments

    I've been tweaking the 3d printable design for the tray.

    Tabs and panel cutouts fit a Raspberry Pi 1, but can easily be adjusted for any model.

    I've also included a way to hold a piece of PCB in place, so it can slot directly into the card edge reciprocal in the SmartSlot.

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pochenk wrote 05/22/2020 at 21:32 point

That doesn't look that easy/normal..
Just watched this one today because i want to hook my SMT1500i and SMT2200i up to a device via serial or CAN

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