# Adding a Spark simulation
The Spark service comes with a built-in simulator. This simulator won't control physical actuators or use OneWire sensors, but also doesn't need a Spark controller to function.
Setting it up is easy.
Navigate to the directory you chose during the installation (default:
cd ~/brewblox), and run this command in your terminal:
brewblox-ctl add-spark --name spark-one --force --simulation
# Using multiple Simulation services
To add more simulation services, run the above command again, but replace spark-one with your desired service name.
brewblox-ctl add-spark --name spark-two --force --simulation
# Converting a service
Blocks and block names defined by a simulation service will not be used by a non-simulation service.
If you originally set up the system with a spark-one simulation service, you can convert it to a non-simulation service by running the following command:
brewblox-ctl add-spark --name spark-one --force
The simulation blocks will be kept, but not used by the Spark controller.