What is a Intellidge ink chip.

Epson fit small circuit boards to most of their ink cartridges. These record the amount of ink that is estimated to be in the cartridge. I read that the official epson line is that it is for the customers benefit and not an anti-refill device. Whether you believe this or not they are a bloody nuisance to anyone wanting to refill the cartridges or use bulk ink. It also stops people using old cartridges full of solvent for cleaning the heads. Another problem was early printer models didn't check if the cartridge had been changed while power was on. This was good if you wanted to trick the printer into copying a “full” chip to and empty one, however the reverse was also true and you could easily copy and “empty” one into your full one.

They are just a small memory device holds 32 bytes of data, they do not measure real ink level and nor does the printer. The printer reads the chips on startup, estimates (sometimes badly) how much ink should have been used and writes this back at shutdown. They hold other data as well.

So epson go to the trouble of fitting chips to cartridges and building all the extra sockets, wiring, electronics and software into the printer so you can use the computer to see the predicted level and it can stop you printing if it think you've used enough ink. High-end Canon's on the other hand make the inks tank clear so you can see and have optical sensor to detect emptiness. This make a lot more sense – unless you are making an anti-refill device that is. Canon almost got my business this time but nobody I could find has run pigment in them – too risky.

To get around the chip problems someone usually end up producing read-only chip which always read full (for use with CIS) and chip reseters for those who want to refill. These are not available for 2100p at the time of writing as far as I can tell.

Before ordering my 2100p I did my homework and it seemed fairly likely a chip reseter would become available at some point and read-only chips as well. I was also cocky enough to think I could crack it myself and I have. It didn't go quite as expected though.

What do I want to do?

I want the easiest way to fool the printer into believing it has full cartridges present so I can build my CIS.

What did I expect?

A logical interface for Intellidge is i2c (i squared c) or TWI (two wire interface). Then the chip could just be some standard i2c eeprom. The Intellidge have too many pads for this but I was hopeful. After that would could SPI or microwire – again this could use off the shelf parts. If the chips were micro-controllers then plain asynchronous serial would be my choice.

I had a look.

To do this I use a AVR mega323 micro, I declined offers of logic analyzers being a homebrew type of guy. The 323 has 2K of internal ram which is enough for some minimalist data logging. It was about $50AUS in parts ($30US) to make. I wired a cartridge to bring the signals out and took a quick look with a voltmeter.

Nothing!

There was nothing there. I expected some power but no, the chips are only powered briefly when the are accessed. I used leds to get a rough idea what was what and hooked up the micro via resistors to give some degree of protection to the printer if I screwed up. The code in the micro was written is assembler and captured data sent via rs232 to my PC where I wrote a delphi program to display and process the data.