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kfix
ddcctl
C2016–2025
kfix / ddcctl

ddcctl

DDC monitor controls (brightness) for Mac OSX command line

Command LineMobile & Desktop
Explore on GitHubRead Hacker News discussions
15Distinct people
19Mentions
0Explicit recommenders
2KGitHub stars
REPOSITORY AT A GLANCE

What to know before exploring

What it is

DDC monitor controls (brightness) for Mac OSX command line

GitHub

Where it is used

No documented product use was verified in the last source check.

What people are saying

No recommendation phrase was found in the indexed comments.

No classified warning is attached to this page. Read the discussions before treating silence as approval.

Also in these discussions

No other repository is repeatedly linked in the same discussions.

This week on Hacker News

Nov 8–Nov 15 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/15/2026, 12:45:45 PM UTC.

No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.

Mentions over time

HN mentions by year19 dated mentions

Observed mentions: 2016-10-26 18:58:14 UTC to 2025-01-28 18:12:13 UTC.

0123452016-01-01 00:00:00 UTC to 2017-01-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 comments20162017-01-01 00:00:00 UTC to 2018-01-01 00:00:00 UTC (exclusive): 1 mentions; 1 submissions, 0 comments2018-01-01 00:00:00 UTC to 2019-01-01 00:00:00 UTC (exclusive): 2 mentions; 0 submissions, 2 comments2019-01-01 00:00:00 UTC to 2020-01-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 comments2020-01-01 00:00:00 UTC to 2021-01-01 00:00:00 UTC (exclusive): 5 mentions; 0 submissions, 5 comments20202021-01-01 00:00:00 UTC to 2022-01-01 00:00:00 UTC (exclusive): 2 mentions; 0 submissions, 2 comments2022-01-01 00:00:00 UTC to 2023-01-01 00:00:00 UTC (exclusive): 5 mentions; 0 submissions, 5 comments2023-01-01 00:00:00 UTC to 2024-01-01 00:00:00 UTC (exclusive): 1 mentions; 1 submissions, 0 comments2024-01-01 00:00:00 UTC to 2025-01-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2025-01-01 00:00:00 UTC to 2026-01-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 comments2025

Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.

View mention counts and date ranges
UTC ranges include their start and exclude their end. Select a period to filter the source evidence.
PeriodStart (UTC)End (exclusive, UTC)MentionsSubmissionsComments
20162016-01-01 00:00:00 UTC2017-01-01 00:00:00 UTC101
20172017-01-01 00:00:00 UTC2018-01-01 00:00:00 UTC110
20182018-01-01 00:00:00 UTC2019-01-01 00:00:00 UTC202
20192019-01-01 00:00:00 UTC2020-01-01 00:00:00 UTC101
20202020-01-01 00:00:00 UTC2021-01-01 00:00:00 UTC505
20212021-01-01 00:00:00 UTC2022-01-01 00:00:00 UTC202
20222022-01-01 00:00:00 UTC2023-01-01 00:00:00 UTC505
20232023-01-01 00:00:00 UTC2024-01-01 00:00:00 UTC110
20242024-01-01 00:00:00 UTC2025-01-01 00:00:00 UTC000
20252025-01-01 00:00:00 UTC2026-01-01 00:00:00 UTC101

What Hacker News says

5 sources
alin23·Dec 19, 2022
I received the same diagnostic in 2017, which coincided with the year I got my first external monitor for my MacBook. Headaches and eye pain became a more common occurence in the first weeks, until I stumbled upon ddcctl [0] and the fact that monitor brightness can be changed from the OS. That's when I developed the first version of Lunar (https://lunar.fyi) to adapt brightness automatically throughout the day based on the sun position in the sky. (reading the light sensor was not possible at the time) That combined with Night Shift (macOS native version of f.lux) fixed most of my problems. I also tried blue light filter glasses but the only effect they had was removing more money from my savings. I feel like this is just modern day snake oil for computer workers. In the end, what fixed all of my problems was a LASIK [1] operation (well a
Read the rest
ctually PRK because I had only a small abberation). I still recommend this to all my friends and relatives who are always complaining about their vision. It did change my life. I still cringe when someone turns on an overhead lightbulb though, I never use those in my home. Turns out this wasn't my astigmatism, it's just that most LED bulbs are simply too bright single point lights. I fit my home with TRADfri warm light lamps hidden behind sofa/door/desk [2], WLED-powered [3] LED strips and simple string lights (like you can see in the front page video on https://lowtechguys.com/volum/) [0] https://github.com/kfix/ddcctl [1] https://en.wikipedia.org/wiki/LASIK [2] https://www.ikea.com/gb/en/p/tradfri-remote-control-kit-smar... [3] https://kno.wled.ge/
In Ask HN: Best tips for reducing eyestrain while coding with astigmatism?
alin23·Dec 10, 2022
macOS apps which I share at https://lowtechguys.com/ bring me $7k/month on average at the moment, and it keeps growing. It started in 2017 when I shared the first free and open source version of Lunar (https://lunar.fyi/), an app for controlling monitors. At that time, there was only a command line for doing this stuff (https://github.com/kfix/ddcctl) and I wanted a more visual way of changing the brightness. So I learned Swift, learned how to bridge the ddcctl C code and call it from Swift, then made a rough interface and published it: https://www.producthunt.com/products/lunar#lunar-5 It turned out people did have a need for this and asked if they could donate. I set up a Buy me a Coffee page and in 4 years collected about $5k in donations. That's a lot of money for a Romanian. When Apple Silicon appeared, Lunar didn't work anymore beca
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use the whole hardware arrangement and drivers were different, and there was no documentation on how to send I²C data. I took the plunge and quit my stressful job, bought an M1 MacBook and reverse engineered the I²C communication: https://alinpanaitiu.com/blog/journey-to-ddc-on-m1-macs/ Then published Lunar 4 as a Free version with a Pro paid upgrade. I was reluctant with this, didn't think anyone would buy it, but to this day I'm able to be unemployed and put my ideas into practice because of it.
In Ask HN: What is the best income stream you have created till date?
alin23·Jun 21, 2022
No worries! The same sentiment is what keeps me enthusiastic about programming day after day :) So computer monitors have support for a communication protocol called Display Data Channel which is normally used by the host (Mac, PC) to get info about supported resolutions, frame rates, signal timing etc. On top of that, a command interface has been created called MCCS or Monitor Control Command Set [1] which allows changing brightness, volume, input and a ton of other aspects of the monitor, by sending specific bytes through the cable. That cable can be HDMI, DisplayPort, Thunderbolt, VGA, DVI. It doesn’t matter, as long as it has dedicated wires to carry the I2C signal. I2C is the 2-wire communication protocol used by DDC, and it basically defines things like “a pulse of 5V (volts) of x milliseconds followed by 0V of y milliseconds means
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the 0 bit. The 1 bit is represented by a pulse of 5V of 2x milliseconds”. It’s a bit more complex than that, also defining TCP-like features with data frames and ACK packets, but you get the idea. It’s something that both devices agree on so that they can send raw bytes using 5 volt pulses. I’ve created Lunar as an adaptive brightness app for macOS after finding out about a little CLI called ddcctl: https://github.com/kfix/ddcctl That’s where I learned how DDC packets look like, where to place the payload (brightness value between 0 and 100, input ID, etc) and how to write that to the monitor using the macOS I2C APIs. When Apple Silicon came out, none of that was possible anymore so I had to go looking around kernel assembly and private macOS frameworks for “the Apple Silicon way” of writing data through I2C. If you’re also curious how I learned that, it’s a very cool domain called “reverse engineering” and I learned it while working as a Malware Researcher at Bitdefender. A bit hard to get started, but so many gems to discover once you know how to open binaries in IDA/Hopper and look around their disassembled code. [1] https://milek7.pl/ddcbacklight/mccs.pdf
In HDMI Firewall
alin23·Mar 23, 2022
The goal for having the non-paid parts open source, is to share knowledge. I have to reverse engineer a lot of macOS internals and some hardware too to make some features possible. I don’t want to keep that for myself. This XDR thing makes an exception because it required a lot more RE work than I expected I’d like to get some publicity for it before open-sourcing and writing it up. I don’t think I can take advantage of the open source community here. The OSS community has largely chosen MonitorControl since it is fully open source, free and accepts contributions. I couldn’t have started Lunar without the open source ddcctl [0] project, and I want to give back as much as I can without jeopardizing sales and having to go back to a 9-to-5 job. [0] https://github.com/kfix/ddcctl
In Show HN: Lunar XDR Brightness control

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