Embedded Etcher

Design files related to a photo-sensitive layering method etching machine everyone can build to produce prototypes quickly at home or in the lab.

Architecture

The etching machine consists basically out of two parts. The first part is a UV light, which is used to develop a photo-sensitive PCB. Once this has been done. The PCB has to be treated with sodium hydroxide (NaOH) dissolved in water. This removes the UV-sensitive plastic, where it has been tackeled by the light.

The second part is the actual etching machine, which is designed to be compatible to euro cards (and even bigger ones). The etching machine is either filled with sodium persulfate (Na₂S₂O₈) or iron(III) chloride (FeCl₃) dissolved in water of course.

Cuvette

UV Light

Driver Extension Board

This PCB is made to fit the Nucleo-F103RB development board from STM. Features:

• 64 LED driving stages
• 3.36 A and 26 V max. input (0.05 A per stage results in 3.2 A)
• 0.1 A max. per stage
• 10 Bit DAC to steer the driver
• Optional potentiometer to steer the drivers
• Control-loop for constant current
• Feedback amplification to get a high current resolution
• I2C header
• SPI header
• 2 rotary encoder and 1 tactile switch

It is important to mention, that the resistors for the non-inverting amplifier in the feedback loop are optimized to result in a maximum current of 33 mA for 3.3 V in order to achieve higher currents different resistor values have to be chosen.

Etching Instruction

TBD