Friday, May 29, 2009


I've been etching numerous PCBs at work for various little projects, and one of the annoying parts of etching is the actual etch process. The copper clad board is immersed in Ferrocloric acid in order to etch away the exposed portions of the board. During the etch, the liquid should be agitated in order to achieve maximum saturation. I got tired of jiggling the tupperware around for 20 minutes, so I built an agitator!

You can see that this project uses the make controller as well as an erector set. I used a HiTec 645MG servo for the agitation.

Here's the video. Rated PG-13 for intense battle sequences and some scary images:

I didn't have anything to etch at the moment, so the video shows the tub with Mountain Dew in it instead. Maybe that would be good for etching designs in teeth...

As you can see, the servo oscillates above and below the horizontal. This ensures that the acid flows both ways.

I made a circuit board for a device we're calling FreePoint. This is the prototype design that's made to plug in as an arduino shield. The final version will be standalone.


Aaron, Vicki Tunell said...

You're so funny baby. Good work on your agitator and the FreePoint. Love you


Exo_UY said...

great work!
Is that the best way to agitate a board? When I do it myself I move the tupper in both ways.

I'll try to build one like this but with a PIC (in my country you can't get neither make controlers nor arduinos, only pics, and now that i think about it is also hard to get servos :( )

Sorry for my bad english and keep the good work!

PS: what does the freepoint do?

Aaron, Vicki Tunell said...

The agitator actually goes positive and negative, so the wave action is both ways.

FreePoint is a wireless network system for controlling multiple atmegas from a single PC.

Anonymous said...

Very innovative, I was glad to see it in action.

Chris said...

Will you be available for free consultation regarding Ian's next Science project??? That would be totally amazing.

B said...

You should also add a thinfilm heater, as the etchant works better if it's warm. Maybe a small one from a car seat - Pick-A-Part?