The Logitech Solar App will make sure your Logitech® Wireless Solar Keyboard K750 for Mac® is always ready when you are. Features include:
• Easy-to-read, at-a-glance status and power-reserve indicators — so you’ll know if your keyboard isn’t getting enough light
• Lux meter so whether you’re getting the full power of a high-watt desk lamp or just the faint light of the moon — you'll know how much power your light source is providing at any time
Ratings and Reviews
Works great. Log issue is fixed.
Donwlaoded and reviewed September 29, 2018: Although there are many 1 star reviews from years ago claiming that the app hogs CPU and constantly writes to the console log, this is no longer the case. If you download the app today, you will get version.1.00.40 and this behaves fine. The app itself has limited functionality but does what it says: monitors the light level being received by your Logitech 750 solar keyboard. In normal room light I get a reading of around 65; with the keyboard in direct sunlight it pegs at 500. It also reports the state of the (rechargeable) internal battery. Donwload without concern!
Log issue seems fixed
First of all, this app works well for showing the light level and your battery charge, as you can see in the screenshots. Really not too much more you could ask for in that department.
Second, I read many reviews about system impact due to excessive logging. I see the version here on the App Store is 1.00, but somehow on my Mac (Sierra) I have version 1.0.40. I suspect the ".40" was released to address the logging issue. I monitored the app with Activity Monitor and also watched it on Console (log viewer) and found that while the solar service did write to system.log once per second while the app was active, it stopped soon after I quit the app. I think the reason it writes this info to the log is to support the application's history feature. After the app had been closed the service did continue to write battery level to the log for a minute or two, then stopped. It then continued to write shorter entries to the log in sporadic bursts.
After about an hour of monitoring, opening and closing the app a few times, it wrote a total 1.3MB to system.log. I don't see this as having a notable impact on performance. System.log is recycled after a while so the file doesn't continue to grow eternally, so space shouldn't be a concern. If you are worried, check around for a free open-source equivalent, I know one exists for Linux and it may be possible to tweak it to work on OS X if nothing else is available.
My main issue with this app is: it's not available on the Logitech site. I spent quite a while digging around on the Logitech site only to eventually run across a post mentioning the Apple App Store somewhere.
Great app, simple
Other than the logging to system.log several times every second, it’s a decent app - nice for checking how much light the keyboard is getting.
If you’d like to ignore logging from the app, as a work-around, do the following:
1. Add the following two lines in /private/etc/asl.conf:
# Ignore messages from Logitech's Solar Service.app
? [CS= Sender Solar] ignore
2. Reboot OR simply restart syslogd by running:
sudo launchctl unload /System/Library/LaunchDaemons/com.apple.syslogd.plist
sudo launchctl load /System/Library/LaunchDaemons/com.apple.syslogd.plist
With Family Sharing set up, up to six family members can use this app.