Normally, the Google Home permits only control by touch and voice and you always need to have your smart phone/tablet by your side to control Chromcasts. Moreover, neither touch, nor voice commands can match the satisfaction that a clickable control offers.
This project implements a 2in1 remote using which you can control both your Chomecast and Google Home. The project costs just about $15 and you need not think twice before handing over this remote to your kids, unlike your smart devices.
DIY Remote control for Google Cast Devices using Raspberry Pi Zero and Pimoroni Button SHIM.
sudo curl https://get.pimoroni.com/buttonshim | bash
sudo apt-get install git sudo pip3 install pychromecast
cd /home/pi/ sudo git clone https://github.com/shivasiddharth/pi-gcast-remote
#Enter the IP Addresses of your Google Cast devices chromecasts_ip=['192.168.1.4','192.168.1.13'] #Enter the names of the Google Cast devices as in the Google App chromecasts_name=['Living Room Speaker','Living Room TV']
sudo chmod +x /home/pi/pi-gcast-remote/scripts/service-installer.sh sudo /home/pi/pi-gcast-remote/scripts/service-installer.sh
sudo systemctl enable gcastremote.service
To switch between the devices, press and hold the A button/key.
Note: pychromecast API takes time to get the list of active devices, hence continuous device status monitoring has not been added as it would cause delays to get a response from a device on button press. So the remote control program should be started after making sure that your devices are online.