Virtual Fireplace [130274]

Fireplace simulator with realistic light and sound effects.

I designed a device that can simulate very well a fireplace. It needs 120V light bulbs (or anything that is dimmable). We can use one set of red lights, to create a deep-red background (not dimmed), plus one set of yellow and white lights (or anything else you like) that will be flickering according to the fire-cracking noise. In fact the device comes with a small (but loud) amplifier that plays the sound of an actual fireplace (downloaded from youtube: there are tons of them), and the yellow and white lights will flicker in unison with it.

110VAC/220VAC versions:

Virtual Fireplace
Virtueel Haardvuur
Virtueller Kamin
Feu de cheminée virtuel

The audio file is stored in a memory card and played by means of a mp3 module TENDA TDB380. All these goods are managed by a tiny Microchip 12F683 (8pin) and two triacs. The red lights are connected straight to the mains, the yellow and white lights are driven by their respective triacs. A LM386 drives a 8 Ohm loudspeaker (approx. 500mW). There is a trimmer to adjust the volume.

The board fits also the transformer, so nothing else is needed. For your convenience, here is a video.

The firmware has been written using mikroC free edition (it's less thank 2k: actually 208 words).

IMPORTANT: suited for North America's grid (120V, 60Hz). DO NOT use anywhere else, since the timings won't work correctly.

Project Elements

sn850778-0.JPG (JPG, 1.33 MB)

Virtual fireplace11.pdf (PDF)

Schematics as PDF

Circuit diagram (JPG, 75.07 KB)

Virtual fireplace top layer MIRRORED.pdf (PDF)

Virtual fireplace bottom11.pdf (PDF)

Virtual fireplace SILK LAYER.pdf (PDF)

12F683 + TDB830 virtual fireplace.zip (ZIP)

Discussion (3 comments)

ClemensValens 11 years ago

We have been informed that the published PCB V1.1 has safety issues around the opto-couplers. We have corrected these problems and hereby present you our new design V1.2.

Sorry for the incovenience caused.

Regards,

Clemens

PDF of PCB (schematic is unchanged) (71kb)
Eagle 6.5.0 files (94kb)

2 Attachment(s) 0 Comment(s)

TimUiterwijk 11 years ago

Adapted the schematic and software to 230V 50Hz.
Choosen a different audio module that is more commonly available.

Build and tested a first prototype. Slight changes in the schematic due to different audio module.

Currently drawing the new schematic and PCB in Eagle.

TimUiterwijk 11 years ago

Here some explanatory text: The virtual fireplace is a module that simulates an actual fireplace by controlling a red, yellow and white light bulb. It also plays the sound of an actual fireplace, creating a real authentic fireplace feeling. So when you run out of wood, you can still ‘burn some fire’ ;). The module uses a 230V to 2 times 6V transformer to create a low voltage for the microcontroller and audio section. The transformed signal is rectified first. This rectified signal switches a transistor that is connected to a microcontroller pin. This signal is used for zero cross detection, required for timing of the triacs. A diode keeps a separation between the rectified AC and DC voltage (created by the capacitor). This DC voltage is used as a power supply for the LM386 audio amplifier. The DC voltage is too high for the audio module and the microcontroller, so a voltage regulator brings the DC level down to 3,3V. The microcontroller uses the busy pin from the audio module to know whether audio is currently playing, and if not, trigger the play pin. This way the fireplace keeps working as long a power is supplied to it. The audio module sends out a mono audio signal to the audio amplifier. The amplifier makes the speaker play the actual fireplace sound. This amplified signal is also fed to the ADC of the microcontroller, which uses this to trigger the triacs and thus controlling the light bulbs. The red light bulb is constantly on, creating a red background. The yellow light bulb is controlled according to the audio level, the louder, the brighter. This creates the flickering effect of fire. When the sound level is really high the white light bulb is triggered as well, making the ‘fire’ really light up. Optocouplers are used to isolate the microcontroller from the 230V. The potentiometer next to the speaker connection is used to control the audio volume. The other potentiometer is to tone down the audio level from the audio module, so the LM386 doesn’t clip and therefore removing distortion.

1 Comment(s)

petrus bitbyter 11 years ago

The circuit can easily be adapted for 230V/50Hz. You'll have to get a 230V mains transformer of course, 230V lamps and better take an 800V version of the BT138. Also replace the 100R (R6 and R10) by 220R ones.

As for the timing I suppose the current timing was found by experimenting. You may do so for 50Hz but that can be disappointing. If you want to keep the circuit and timing (almost) unchanged, build a 120Hz pulse oscillator that produces pulses of a 50-100us. You can take transistors, a 555 or even a PIC for it.

If you like to go for a PIC, the smallest one will do. But you can also go for using the TMR1 of the PIC12F683 that is currently not used. So instead of the Interrupt On Change you have to use the TMR1 interrupt. This will of course require some changes in the software but the impact on the timing wil be minimal.

petrus bitbyter