liminalsunset

3 anni fadiscuss

The reason users' real names are in the hostnames is possibly because of AirDrop. The system appears to use the hostname for things like Personal Hotspot and AirDrop, and other types of names would probably lead to widespread confusion when it came time to share a file.

liminalsunset

3 anni fadiscuss

Speaking of heat pumps and granular control, I recently figured out that some Midea heat pumps (usually sold rebranded to various brands) contain two interfaces to get and set detailed information:

1) Detailed diagnostics i.e. RPMs, feeds, speeds, currents, temps etc can be read from the high voltage signal line between the indoor and outdoor unit - there is an official tool (search "Dr. Smart Midea" on YouTube) that does this. If you look in the right places, there is a PowerPoint with a schematic of the PHY that you need to interface with this using a LV isolated controller

2) The outdoor unit can be driven manually using the same tool using an i2c port that is on the PCB on the outdoor unit

I have the new generation of their Dr. Smart tool, which I haven't had the time to thoroughly test or document. If there is interest I will likely try to reverse engineer and document these protocols properly.

> "I want to be my own mechanic, and if I'm not that mechanic I want to be able to have anyone be that mechanic."

> "Do you want to know what the active airflow rate is? I want to know what the active airflow rate is. Do you want to know power consumption? I want to know power consumption. Do you have a way to write unique schedules/programs that get executed on the heat pump? I want a way to write unique schedules/programs that get executed on the heat pump."

There's one feature of this diagnostic interface that I really really like. It allows you to "drive" the hardware of the unit manually, like Program Auto mode on a camera. You can manually set the frequency of the compressor and fan, and the control board will continue to enforce safeties.

I haven't tried yet, but something I really want to try to implement myself is "frequency lockout". This is a common feature on commercial variable frequency drives. I noticed that under some operating conditions, the unit vibrations resonate with the building and create unpleasant sounds - I'd like to program it to never dwell on that frequency and skip over it.

> The desire is to have any control/knowledge you'd want to have as the creator/developer.

While I was exploring this, I had this in mind constantly. I definitely had this diag interface in mind when I was selecting a unit.

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