Audio signal driven analog flame display
A “flame show” is responsive to an audio input signal such as music. A base unit including an analog base unit controller circuit is arranged to receive an audio input signal and generate an analog control signal that is responsive to the audio input signal. The analog control signal is distributed, by wire or wireless, to one or more flame display units such as a “tiki torch.” Each flame display unit has a fuel source, and a proportional valve for controlling an amount of fuel supplied to a burner. Preferably, the control signal controls a gate terminal of a MOSFET semiconductor device, which in turn is coupled to control current in the proportional valve each each unit. By deploying multiple flame display units, all coupled to the same base unit, all of the flame display units contribute synchronously to the overall flame show.
1. A system comprising:
a base unit including an analog base unit controller circuit arranged to receive an audio input signal and generate an analog control signal that is responsive to the audio input signal;
a control wire connectable to the base unit to distribute the analog control signal; and
a flame display unit electrically connectable to the control wire to receive the analog control signal;
the flame display unit including a combustible fuel source to generate an open flame;
and the flame display unit including a proportional valve to control flow of fuel from the fuel source so as to controllably vary a height of the open flame responsive to the analog control signal during operation of the flame display unit;
the flame display unit includes a flame control circuit arranged to receive the analog control signal and generate an analog valve position signal; and
the flame control circuit is coupled to utilize the analog valve position signal to control electrical current in the proportional valve during operation, thereby producing an active flame show responsive to the audio input signal; and
wherein the analog base unit controller circuit comprises:
an input section to receive the audio input signal;
a full-wave rectifier circuit coupled to the input section to rectify the audio input signal to form a rectified signal;
a low-pass filter circuit coupled to the full-wave rectifier circuit to filter the rectified signal to form in interim signal, the low-pass filter having a roll-off frequency selected based on response characteristics of the proportional valve; and
a current summing circuit to combine the interim signal with a predetermined DC offset voltage to form the analog control signal, for setting a minimum drive current in the proportional valve during operation.
2. The system of claim 1 wherein the flame control circuit includes a power MOSFET semiconductor device coupled to the proportional valve to control valve current responsive to the analog control signal.
3. The system of claim 1 wherein the flame control circuit includes a current feedback closed loop control circuit for controlling the proportional valve current.
4. A system comprising:
a base unit including an analog base unit controller circuit arranged to receive an audio input signal and generate an analog control signal that is responsive to the audio input signal;
a wireless transmitter arranged to transmit a wireless control signal based on the analog control signal; and
a flame display unit including a receiver to receive the wireless control signal and recover the analog control signal from the wireless control signal;
the flame display unit including a combustible fuel source to generate an open flame;
and the flame display unit including a proportional valve coupled to receive the analog control signal and to control flow of fuel from the fuel source so as to controllably vary a height of the open flame responsive to the analog control signal during operation of the flame display unit.
5. The system of claim 4 wherein:
the flame display unit includes a flame control circuit arranged to receive the analog control signal from the receiver and generate an analog valve position signal; wherein
the flame control circuit is coupled to utilize the analog valve position signal to control electrical current in the proportional valve during operation, thereby producing an active flame show responsive to the audio input signal.
6. The system of claim 5 wherein: the flame display unit is coupled to a low-voltage DC source to power the flame display unit.
7. The system of claim 6 including a power supply to provide the low-voltage DC source to multiple flame display units.
8. The system of claim 4 wherein the analog base unit controller circuit comprises:
an input section to receive the audio input signal;
a full-wave rectifier circuit coupled to the input section to rectify the audio input signal to form a rectified signal;
a low-pass filter circuit coupled to the full-wave rectifier circuit to filter the rectified signal to form in interim signal, the low-pass filter having a roll-off frequency selected based on response characteristics of the proportional valve; and
a current summing circuit to combine the interim signal with a predetermined DC offset voltage to form the analog control signal, for setting a minimum drive current in the proportional valve during operation.
9. The system of claim 4 wherein the flame display unit includes a flame control circuit arranged to receive the wireless control signal and the flame control circuit includes a power MOSFET semiconductor device coupled to the proportional valve to control valve current responsive to the analog control signal.
10. The system of claim 9 wherein the flame control circuit includes a current feedback closed loop control circuit for controlling the proportional valve current.