Shutting Down the Mac Mini

**vr4** · 07-17-2005, 07:38 PM

I'm hoping this won't be stepping on anyone's toes. I'm speaking mainly about Mike here. I understand Mike has done a huge amount of work on the power supply for the Mac and it is just the shutdown issue that remains.

Basically I have found a solution, or at least someone who is able to give us a solution. The answer came from a bit of investigation into how the UPS manufacturers solve this problem. Essentially the software has to run root privileges in order to do what we want. So ... it IS a software issue as someone pointed out a long time ago.

Given that using a UPS isn't something I really want to do, the guy I spoke to says he can take a signal from a shutdown controller and then tell his software to shutdown in 'X' amount of time. Theoretically if we could rig up a circuit that would monitor battery voltage and 'tell' the software when our car battery was getting low, we could even tell it to shutdown when battery voltage falls below a certain critical level. Personally however, I think the first option is more than sufficient and that for the vast majority of us leaving the 'time to shutdown' somewhere between 36 and 48 hours would be ideal.

I imagine this software is patented, so I don't think there is any way unfortunately we can pass this onto Mike when it's done. I will be doing this for my car and so I'll be getting a power supply from Mike soon to get the integration stuff sorted out. Once that's done and we have confirmed it works I'll post some more.

On a side note, Mike if you are reading this, the guy is just as unfamiliar with shutdown controllers (and how to get a signal from the ignition to the software program to let it know the car has been switched off), as you are about OS X programming. If you think it is worth you contacting this guy and seeing if you can negotiate a deal with him to work together for a seamlessly integrated project, then PM me and I'll give you his details.

Paul.

**MikeH** · 07-18-2005, 10:30 AM

While Paul and I discuss the merits of this 3rd party software, let me pose a question to the Macommunity....

What if I put a default countdown timer in the P1900 that, unless it was reset by restarting the car occasionally, would time out after 36-48 hours and kill the power being applied to the Mac mini? This way you could continue to enjoy the fast startup times of "sleep" mode if you use the car regularly, but would also have peace of mind that, if you let your car sit for "an exteneded period of time" it would turn off completely. Remember, the P1900 already has a low battery detection capability that will kill the "keep alive" power to the mini if the battery voltage dips below about 10.5 volts during sleep.

Would this feature be helpful?

**jdkarr01** · 07-18-2005, 12:07 PM

Although I can see the use for the countdown of say 36-48 hours I also think that the low bat monitor does most of the job for us. It really depends on how much work it would be. If it wouldnt take much it would be a nice safety. However, is it really worth it if it is going to be a big hassel. Just my two cents. Thanks guys for all of your help. Oh and if you get a software solution that is command line let me know and Ill try to integrate it into iKarr.

**raceer** · 07-18-2005, 03:12 PM

Hi Mike

Yes, that would be useful. This way u would not have to wait for the 'low bat' to kick in and have a controllable default AND you could have the 'low bat' as a backup

Plus some cars may not like 10.5v to play with.

Thanks

**Bugbyte** · 07-18-2005, 04:23 PM

I think this is a nice feature IF there is no software solution.

**Adrian-S** · 07-18-2005, 09:35 PM

I'm not sure if this will help, but here are my thoughts. I'm in the process of researching what to do for my car, and having this mini sitting here seems like a decent option for me instead of buying a small pc.

The down side to using the mini: I prefer not to cut my power supply wire, if the carputer route doesn't work out, I'll most likely sell the mac and having a cut/spliced cable isn't going to help much.

The other item that I'm having difficulty in finding a solution to is the automated shutdown. The closest method I could think of was to use a UPS with data cable that has software installed on the machine, and it shuts down when the UPS loses power. I haven't gone far enough in locating a ups model and software for the mac yet.

-adrian

**vr4** · 07-19-2005, 07:24 AM

Guys,
There is no real secret to this. All that I have essentially found is a third party piece of OEM software which has already been built for use with a number of UPS devices. The point is that at present to use it you need one of the UPS devices that are currently compatible. All that I have done so far is to try to get Mike to come in on the discussions I have already had with the software programmer. He has already agreed with me to take a small hardware cable with an electronic relay that can sense an input from the P1900 and communicate with the Mac to instantly shut it down or tell it to turn off after 'X' minutes/hours etc. In fact, if the P1900 already has a voltage detection circuit to tell it when battery voltage reaches 10.5 volts, I am pretty sure the output from the P1900 could be rewired to signal the input to the relay to shut down the Mac Mini properly rather than just cutting the power when the battery voltage gets too low. I have no doubt that this is feasible, and I will definately be following through and doing this. The only thing I think you guys have to consider is if you would be willing to pay the $20 USD for the software. I personally think it is a small price to pay for the perfect shutdown solution.

Paul.

**maxipad96** · 07-20-2005, 07:57 PM

Just to let everyone know. I went out of town for 1 1/2 weeks. Left my mini on sleep. Absolutely no problem at all. It was right where i left it. Started up just fine too.

I have only had 2 awkward re-boots since installing the mini in my car apx 2-3 months ago. This is better than I can say for my daily desktop Dual G5.

I doubted the sleep process at first, but now question why anyone WOULDN'T sleep their mini.

**Bugbyte** · 07-20-2005, 08:33 PM

Wow. I would have thought you'd return and it would have been shut down. Very nice to know.

**FireAnt** · 08-03-2005, 09:59 AM

I'm thinking about setting my p1900 to the sleep mode to enjoy faster startups. How many people are doing this and has anyone experienced the low battery problem yet?

Thanks,
Mike