Here is a basic flow which does what you want.
Replace the inject
and debug
nodes as required.
And adjust the frequency too as required.
[{"id":"d5fdca2.390b0b8","type":"inject","z":"a941e919.4a7d88","name":"","topic":"","payload":"start","payloadType":"str","repeat":"","crontab":"","once":false,"onceDelay":0.1,"x":220,"y":2270,"wires":[["310dcbed.f8124c"]]},{"id":"f3bf6ab5.45f388","type":"inject","z":"a941e919.4a7d88","name":"","topic":"","payload":"stop","payloadType":"str","repeat":"","crontab":"","once":false,"onceDelay":0.1,"x":220,"y":2320,"wires":[["310dcbed.f8124c"]]},{"id":"310dcbed.f8124c","type":"trigger","z":"a941e919.4a7d88","op1":"1","op2":"","op1type":"str","op2type":"nul","duration":"-1","extend":false,"units":"s","reset":"stop","bytopic":"all","name":"","x":400,"y":2270,"wires":[["6a7d8b0c.1d1adc"]]},{"id":"6a7d8b0c.1d1adc","type":"debug","z":"a941e919.4a7d88","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","x":580,"y":2270,"wires":[]}]