Lightning itself is a pretty lightweight protocol and can easily be run on a raspi 3. However without neutrino a lightning node needs to have access to a Bitcoin full node. Most people seem to run the Bitcoin node on the same machine as the lightning node. While a raspi3 can run both the processor is a little week to verify the entire blockchain. So expect a long time (couple of weeks) for initial blockchain sync or run a remote Bitcoin node.

To use lightning you will need a Bitcoin full node.
As hardware you can use:

1. PC/Laptop
2. Dedicated Server(VPS Server)
3. Raspberry Pi 3(With external HD)
4. ...

If you want to use the Raspberry Pi 3 make sure to sync the Bitcoin blockchain on an external more powerful device and then move the blockchain to your Raspberry Pi 3 Harddrive. As Rene Pickard pointed out, the Raspberry Pi 3 is not so powerful and syncing there would take some time.

You can also try Neutrino(experimental) or use a remote full node and connect via rpc.

I'm using a Raspberry Pi 3B (with 64GB card) and an external HD that contains the blocks. So far it works fine, CPU temp is around 57°C. Syncing took a few days (2 or 3). I used the RaspiBlitz image + tutorial. This installs step by step your Bitcoin node and your Lightning wallet. https://github.com/rootzoll/raspiblitz As it's hosted at my place and I want to have a public node, I also did port forwarding (n° 9735).