How to turn boolean switch on for designated period of time

Hi Everybody,

I’m trying to incorporate a boolean switch from the dash-daq library and I would like to be able to turn the switch on manually, but then have it turn off automatically after a certain number of seconds. I think this should be possible, but I don’t really understand how to do this. I tried creating a callback to click a button after the switch gets turned on and then setting another callback to trigger on the button click, but that didn’t seem to work. Here is what I tried so far:

import dash
import dash_daq as daq
import dash_html_components as html
from dash.dependencies import Input, Output
import time

external_stylesheets = ['https://codepen.io/chriddyp/pen/bWLwgP.css']

app = dash.Dash(__name__, external_stylesheets=external_stylesheets)

app.layout = html.Div([
    daq.BooleanSwitch(
        id='my-boolean-switch',
        on=False
    ),
    html.Div(id='boolean-switch-output'),
    html.Button(id='button',n_clicks=0,style={'display': 'none'}) #hidden button to add timer functionality
])


@app.callback(
    [Output('boolean-switch-output', 'children'),
     Output('button','n_clicks')],
    [Input('my-boolean-switch', 'on')])
def update_output(on):
    if on:
        n=1
    else:
        n=0
    output_string = 'The switch is {}.'.format(on)
    return (output_string,n)

@app.callback(
    Output('my-boolean-switch', 'on'),
    [Input('button','n_clicks')]
)
def boolean_switch_timer(n):
    if n==1:
        time.sleep(10)
        return False
    else:
        raise dash.exceptions.PreventUpdate

if __name__ == '__main__':
    app.run_server(debug=True)

This is the exception error that I got:

Circular Dependencies3:17:06 PM

Error: Dependency Cycle Found: my-boolean-switch.on -> button.n_clicks -> my-boolean-switch.on

I think I understand why I’m seeing this circular dependency error, but I don’t really know how else to accomplish the timer functionality. If somebody has an idea, I’d really appreciate any suggestions. Thanks in advance for your help!

Ben

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