Is a special device required to get the home pod to turn on or off my lights?

It requires...lights! But lights which are compatible with HomeKit, and this makes them usable on an Apple device. Apple has a list here you can consult and there are many from which to choose.

I have three in our house with more to come at some point. All are controlled by Home and also the app from the developer and manufacturer, in our case NanoLeaf. You can use either, but HomeKit is for want of a better expression a software hub. It co-ordinates all the HomeKit devices in one place so you don't have to use all the various apps individually. You set it up with the device's app, and from there add it to the Home app but once it is in the Home app you're all set. Once you've done that all the settings are copied to all your devices signed into your iCloud account - and this is further shared with members in a Family Sharing group if you have one set up.

Two of the lights are beside our bed and I've used Home to turn them on every night at 11pm. Another in an adjacent living room, some distance from where usually we are to be found, is set to turn on at 7pm so that end of our house is not in darkness. This works very nicely indeed.

You can also use Home to make settings as I've described, but with a particular colour, hue, and brightness.

The best bit though is that you can use Siri on a device to turn the lights on or off and to change colour or brightness. We also have a HomePod and this too can be used to do the same.

If you have a HomePod, Apple TV or an iPad which is on permanently, you also have the ability to use the Home app on the Internet when you are away from home, not just for the lights but for any device in Home.