iMac SMC Controller for G5 G4

iMac SMC Controller for G5 G4

This thread is about the creation of a standardised SMC circuit and PCB design that could be used in iMac G5 ( and G4 ) modifications, to provide an easy way for a builder to implement advanced functions. If you have a read of these two posts, you can get an idea of what features are possible with such a configuration :

http://www.tonymacx86.com/imac-mods/107859-kiwis-next-project-imac-g5-10.html#post766724
http://www.tonymacx86.com/imac-mods/130197-mactester57s-imac-g5-17-a1058-model.html#post810005

Some of the key requirements would be:

1. The board design would have to fit as many different models of iMac as possible, although simple size constraints would mean that an G4 and G5 would probably (my opinion) need there own board.
2. With such a design it would have to be modular, i.e.. If you didn’t need a feature you could simply not install the needed components.
3. There would be a single firmware codebase, that would run on all devices. Part of the modular design would allow features in software to be enabled/disabled by configuration
4. The board would have to be DIY friendly, i.e. using commonly avalable through hole (no surface mount) components, to make it easy to assemble.
5. The board itself would need (my opinion) to be double sided, meaning it would have to made by a manufacturer, not something you could etch at home.
6. The board design would be open source.

Question: Is anyone interested ?

Secondly, If you are interested what iMac would you like to use this device in? What sort of features would you like to see? Is there anything you would do differently than what you have seen thus far?

If there is enough group interest then this project could go ahead, at this point I am designing a board for myself, which may (my understanding) get modified and adopted by MacTester in due course.

Features

The Below is a WIP

Feature​	General​	iMac G4​	iMac G5​
Size and Location	-	Mount in "Maintenance Opening" on the back. How big is this space ?	17" - Max 95x64mm; Component height in top right corner <= ~ 8mm
Fan Speed Control	Mandatory; Controlled by (dual) DS18B20 Temp sensors	Assumption of one Standard Top Mount PWM PC Fan	Three Original 12v Case Fans
Inverter Brightness Control	Mandatory; Primarily From USB Input, option for capacitive touch sensors	What are the inverter brightness voltage requirements?	Inverter is controlled by 0.7v to 3.3v
Sleep LED	Mandatory; Controlled by Power State of CPU
ATX Power Control	Controlled by Power State of CPU	Not sure is PSU is reusable? Esterhernd? If replaced Pico PSU can be controlled by CPU	Non-Isight iMac G5's have a ATX PSU which needs to be controlled; Isight Models have a PSU which provides standby Power which can be used directly by CPU? Esterhernd?
Power On Chime	Optional; ISD1820; or WTV020-SD using internal speaker	Has a single internal speaker which can be directly wired?	Internal Stereo Speakers could be selected by relay? ; or a secondary speaker used
Audio Amplifier	PAM Amplifier	Optional; Has internal Amp, driving external speaker; Many Mods expose un-amplified audio;	Mandatory; Connected to internal speakers
...

Kiwi

Hello kiwi,

Recently I started to mod an iMac G4 17" (yet another NUC mod) and had similar idea as you. Basically instead of using several picaxes for every function I would put everything into a 14M2.

I hope it will be capable of running the fan pwm (based on DS18B20 temperature readings), brightness (via touch buttons) and sleep led control in parallel. For the chime I would use a WTV020-SD (mp3 module with microSD card) + LM386 amplifier + original internal speakers, then I only have to control start/stop with the picaxe.

I'm still waiting for my 14M2 to arrive and will post my results - as well as my mod details. Of course this is my 1st try on picaxe and there may be hiccups.

But to sum it up: i'm in!