Wooo! First post!
OK let’s get going. This idea came to me when I saw this on thingiverse. I wanted to take it a different direction. Originally the base was just going to say daft punk in their logo with the helmets on springs at the top as bobble heads. But I figured why stop there?
I had been experimenting with synths a lot recently so it’s an electronic band, why not throw a simple synth in there? Due to their kind of dirty sound (at least off of Homework) and ease of mounting, I wanted my output to be a piezo buzzer. I started off with a 4 op amp synth circuit so my low frequency oscillator and my tone oscillator could have 2 different waves each. I was having trouble getting that circuit built right so I couldn’t get it to work but I’ll come back to it eventually. What ended up being better for the buzzer output was to use 2 555 timers (or 1 556 which is what I did on the final project). It is limited to only a square wave but I’m happy with it.
The interface is simple.
3 pots; volume, tone, lfo frequency
3 switches; on/off, pot/light resistor (for tone), lfo on/off
1 Light resistor; optional tone control
2 led; on/off indicator, lfo tracker
2 daft punk bobbleheads; aesthetics/awesomeness
The circuit is pretty basic. I don’t think it’s simpler than the APC but it’s a decent entry level synth circuit. Both timers are operating in astable mode with potentiometers to modulate the frequency. One is operating as an LFO (Low Frequency Oscillator) and the other is operating as a VCO (Voltage Controlled Oscillator). I will have a post soon about some useful and basic synth design circuits and tools. A super useful page on 555 timers in astable mode is here. Other components were chosen to get a particular frequency out of the oscillator, for instance the LFO staying below 20 Hz.
The enclosure was modeled in Fusion 360, the logo came from here and the heads came from here and here. I built in a sliding door in the back to change the battery, adjust the led brightness with trimpots, and to put all the components inside. To save on how my printer generates supports, I designed my own into the part that break off once complete.
Some things I would like to change possibly are maybe move away from the 3d printed enclosure. Things like laser cutting are more suited for a thin walled enclosure that won’t warp. I don’t have access to one so I’m stuck with the 3d printing I guess. After I made this I started experimenting with acetone vapor smoothing. That would make the product look much more clean and polished. I didn’t etch a board for this project because it was so simple. You could theoretically do that with the schematic on your own. I haven’t done that since I’m not great at etching boards as of the writing of this post.
Here are some pictures and other info like where to find the .STLs and a BOM.
|IC1||NE556||DUAL 555 TIMER|
|LFO_SWITCH||DPDT||MINI TOGGLE SWITCH|
|ONOFF_SWITCH||DPDT||MINI TOGGLE SWITCH|
|VCO_SWITCH||SPDT||MINI TOGGLE SWITCH|
The springs are 1/4″ inside the coil and the bolt for the door is a #8 machine screw. You’ll probably have to cut it down to size to fit flush. 2 #4 machine
screws, washers and nuts are also needed for the piezo speaker.