Inker – The Hand Inkjet

One of our Hackaday favorites, [Sprite_tm] made my morning when he sent this in. He built a driver circuit for a HP inkjet cartridge that allows him to print by hand. Ideal for printing on other people, their white boards or their beer. He had to do some blackbox reverse engineering to figure out what the onboard driver chip does on the cartridge. Considering the task, the circuit is surprisingly simple. It has some ATTINY brains, some driver transistors, a data bus and a DC/DC power converter to get the required 1.21 gigawatts, er 20 volts to drive the cartridge.

22 thoughts on “Inker – The Hand Inkjet

  1. Actually, “jigawatt” is a correct pronunciation of the word gigawatt. And it was said that way in the film, because they had heard someone say it that way, and were unfamiliar with the word.

  2. This kinda reminds me of the effect that guy got from his street painting bike, I can’t remember what it was called but he ride it around NY spraypainting messages on the streets.

  3. This is only vaguely related,but I had an idea.I wanted to make a murral painter.It would have to print with some type of paint.That way I wouldn’t have to pay an airbrush artist to do flames or murrals on my ride.

  4. just another example of mordern man turning out another load of rubbish there must be more to life than this bring back steve i say at least he was amusing how this site survies is beyond me next load of crap plz

  5. Hack-a-day has had a bit of a brain-drain due to people being put off by the negative comments and bickering. I hope this helps to bring it back. Now, on to the printer…

    It’s a great idea, actually. Most people don’t know how the printers work. HP cartridges are the only ones this will work with (most others have a separate print head, which means more cost if you damage something). Now, the link to parallax posted farther up I’ve known about. I like this one better due to the more general purpose response and the SIGNIFICANTLY LARGER TANK! The parallax one uses one of the tiny cartridges. Also, since this one is the larger, single color tanks, it’s easier to make a full color print.

    Now, printers these days are dirt cheap, I know. I’m also not a fan of HP, but I do know of one real use for this. There’s a lot of people who make their own CNC routers these days. Replacing the router head with a single cartridge or a “color box” would give you large scale printing capability, say, if you wanted to make your own plotter. It would also let you print on things that you normally couldn’t shove through a plotter.

    I do see another option for the handheld unit beyond what’s suggested by the writer: add a wheel encoder, so the microcontroller can time its printing and you get something more consistently legible!

    I wonder if there’s a pressure hole like on Epson cartridges, so you could put a little pressure (only a PSI or two probably) that could help keep the flow going.

  6. I am still not sure how the lettering stays consisten do you move your hand based on visual feedback from the medium you write on? So once you start seeing the appearance of a w you move slightly to the right for the next letter?

  7. I saved a printing head from an HP 500 A0 printer just to try something similar. This printing head can print a strip of 12.7mm (1/2 Inch) wide in one go. If the control circuit is anything similar, then that should save me a lot of work.

  8. pretty interesting hack. I think that it woudnt be hard to recycle an old ball computer mouse for two encoders, and it would make it better to hold and use…
    Add a keyboard or simply five keys (think of baudot) and you’ve got a typewriter.

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