Inker - the hand inkjet

Posted Oct 8th 2006 8:55AM by Will O'Brien
Filed under: misc hacks

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.

Reader Comments

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1. "to get the required 1.21 gigawatts"

I'm guessing you were watching Back To The Future?

Posted at 9:32AM on Oct 8th 2006 by Adam

2. In the Movie he accually said 1.21 Jigawatts because the producers thought that it had more emphasis.

Cool Project though

Posted at 9:48AM on Oct 8th 2006 by Karl

3. 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.

Posted at 9:53AM on Oct 8th 2006 by David Maher

4. Back to the Future was on tv last night. I believe it was on Bravo at 8pm?

Posted at 10:57AM on Oct 8th 2006 by Mike

5. 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.

Posted at 11:07AM on Oct 8th 2006 by lizard.boy

6. I recommend this kit. It comes with a book (available separately) which explaines clearly what it takes to drive the cartridges.
http://www.parallax.com/detail.asp?product_id=27949

Posted at 11:41AM on Oct 8th 2006 by Bob Reynolds

7. This is pretty cool, I am already thinking of other uses for it - most of them illegal.

Posted at 2:10PM on Oct 8th 2006 by fucter

8. man thats neat. i wonder if you could do perspective changes of the letters by holding the nozzle at different angles

Posted at 2:46PM on Oct 8th 2006 by jj

9. 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.

Posted at 6:16PM on Oct 8th 2006 by cyb0rg777

10. now that's pretty funny

Posted at 8:12PM on Oct 8th 2006 by trebuchet03

11. Seems to me that the hand inker could be used to layout some pretty edgy tattoos. Perhaps a barcode and expiration date for my girlfriends ass?

Posted at 8:10AM on Oct 9th 2006 by Brad Myers

12. 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

Posted at 8:43AM on Oct 9th 2006 by mr dacram

13. 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.

Posted at 9:49AM on Oct 9th 2006 by SOI Sentinel

14. 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?

Posted at 1:05PM on Oct 9th 2006 by michbound

15. 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.

Posted at 1:38PM on Oct 9th 2006 by jwstolk

16. thanks Bob Reynolds, thats a great link. also check out the video of the handheld printing on that site:
http://www.parallax.com/dl/mm/video/SXhandheldprinter.MOV
and the printing bot:
http://www.parallax.com/dl/mm/video/BS2BoebotPrinter.MOV

Posted at 1:50PM on Oct 9th 2006 by jwstolk

17. Who are these people?
http://cdn5.tribalfusion.com/media/612296.gif

and why the hell do they not mind that their picture is being shown all over the internet?

Posted at 2:26PM on Oct 9th 2006 by Mooooooooo

18. Back to the Future is on just about every night, if you look around :)

Posted at 8:10PM on Oct 9th 2006 by Max Kelley

19. I think the link in post 17 causes floating popups?

Posted at 9:37AM on Oct 10th 2006 by dylan willemsa

20. 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.

Posted at 2:45PM on Oct 10th 2006 by pingoart

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