Reverse-engineering an Epson Automatic Roll Paper Cutter (part 2)

I wanted to duplicate all the functions of the thing. That meant using the optical sensors on the ends to limit travel, and implementing some method of driving the cutter back and forth. I could have used a simple button, and let the Arduino do the whole operation automatically, but wouldn't it be more fun to use a Nintendo Wii Nunchuck and move the cutter manually?

I integrated a nice Wii Nunchuck Arduino library, set the motor supply to 24VDC, and presto!

It all works. The code uses the sensors to stop the cutter from moving past the limits. The LD1947 is limiting current to the motor to 0.1A no matter what voltage I use, so power consumption is minimal. And using the nunchuck was super easy.

Reverse-engineering an Epson Automatic Roll Paper Cutter (part 1)

I found a printer (Epson Photo 2200, already dead, I swear!).  After scavenging all of the useful parts from the main printer, I turned my tools to the Automatic Roll Paper Cutter. I didn't think there would be much to it, but inside was a nice motor controller IC (Sanyo LB1947), a couple of IR sensors, and a motor. The motor drives the cutting blade back and forth through a cogged belt. The IR sensors tell the printer's controller when the cutter is at either end. The motor controller helps the printer's processor drive the motor and keep it from going over-current.

The first step was to Reverse Engineer the paper cutter board and make a schematic in KiCad. Armed with the device datasheet (thanks, Google!), I attacked the board with a multimeter and some patience.

The writing on the small resistors is too small to read (except for the 200R and 0R36), so the measurements in the schematic reflect what they measure in-circuit. They're 0402-sized components, so I'm not likely to try to change them out anyway.  The capacitors are a similar story; I'm sure only of the value of the big electrolytic.

Later, I'll hook the circuit up to an Arduino and see if I can make it cut paper!