Since I’m currently waiting on having my first Gado 2 PCB fabbed by BatchPCB, I decided to spend the morning creating a complete mockup of the device’s electronics. I grabbed a mini breadboard and a box of (colorful) jumper wires from Radioshack, and connected everything up according to the schematic for the soon-to-arrive PCB.
For those of you who haven’t been following along, I decided to replace the original articulated arm of the Gado 2 with an arm featuring a single mini linear actuator. The actuator acts just like a servo motor, and can take position commands directly from the Arduino microcontroller (using PWM). This will reduce the complexity of the overall device, and make the arm a lot easier to assemble.
You can also see in this picture that my new pumps have arrived from China (more on this later)!
The pump is controlled by an external motor controller, which is also tied into the Arduino (also via PWM). This allows for variable suction, with 255 different suction levels selectable in the software. The pump (as well as the new actuator) runs on 12 volts. I decided to replace my original ATX power supply with a little wall-wart, which means that all the electronics for the Gado 2 can now reside on its arm, lowering the footprint of the device dramatically. Another neat addition to the design is a current sensing board, which determines the current flowing through the pump; block airflow by picking up a photo, and current jumps; the board detects this, providing another indication that the machine has grabbed something successfully.
After mocking up all the electronics on the breadboard, I wrote a quick control sketch for the Arduino, and fired the machine up. Low and behold, it lifted a test photo on the first attempt!
Next steps include tweaking the amount of suction the pump produces using a physical relief valve, swapping out the stock servo in the arm with one modified for 180 degree rotation (right now the arm’s movement is pretty funky), and choosing a better barb to connect to the suction lifter cup.
Overall, though, it looks like the first draft of the machine’s electronics should work out well. Let’s just hope that I wired everything up correctly on the PCB as well as the breadboard