Needed to make a vibration table on the cheap. Bought this subwoofer in halfords:
The plan was to stand it upright and attach a table to its speaker cones and then use it for doing vibration testing on electronics parts. Thei nice thing about this system is it comes with an integrated amplifier so I can just plug in a regular 3.5mm audio jack from a PC or raspberry pi to generate the audio signals.
So I got it and just started taking it apart basically:
First thing on the list was to modify it so that it can stand upright. (It was designed to be placed sideways in the boot of a car)
Here is is put back together:
The difficult part was 3d printing a mounting point that fit onto the speaker cones. Ultimately it was getting glued on but I wanted it to match the shape of the cone accurately to get the most mating area. Since this is literally going to shake for hours/days on end its important that the glue has enough surface area to work effectively.
I could only fit half of the circle required on my 3d printer so I split it into two pieces:
At this stage I epoxied the speaker cone mounts on to the speaker cones.
Then a raspberry pi with a 7 inch touchscreen was added. The Pi is handy because it has a 3.5mm audio out jack which was used to generate the sine waves which get fed into the subwoofer. Also added a reference accelerometer to the table. The plan is to write closed-loop control scripts that can run through various vibration test standards.