Hacking the HP45

[Catniped]

ah, thats a pity, how much do the results differ between the v3 and v4? also, are there any other printheads which are controllable and can compete with the hp45? the xaar128 looks good but a bit expensive and looks like it has worse specs than the hp45

[dragonator]

Hello,

The biggest difference between V3 and V4 is printing speed, due to the use of DMA. Ease of manufacture and self checking capabilities are a bonus on the V4. Printing quality is exactly the same, since the printing quality comes mostly from the HP45.

I do not know of any other printheads that are open, and of equal quality. The HP84 is interesting, but I never spent enough time to get it to work. The Xaar128 is actually quite good, but designed for other things.

The best project you can look for is Sprite_TM's magic paintbrush. It is here: https://spritesmods.com/?art=magicbrush

I know nothing more of this project, but hope it can be helpful.

[Catniped]

so in the end i decided to pull the trigger and order the hp45, as the xaar128 didnt seem nicer to control or better spec wise than it anyways, and they also ghosted me about the irix

now im wondering, what should be the first thing i should do with it? im not sure if redesigning the boards for another mcu is the best course of action right away, is there another way to atleast test it or play around with it? im fine with ordering some pcbs or pogo pins but prototyping a new board before i get the hang of how to work with the head might not be the greatest idea

[dragonator]

There is a breakout board design in the make package on the Oasis page (https://hackaday.io/project/86954-oasis-3dp) (https://hackaday.io/project/86954/files). This is a KiCAD board design that you can use. It uses the HP45 connector to interface with the HP45 inkjet printhead (https://www.tindie.com/products/dragona ... connector/)

This breakout is compatible with the HP45 carrier used in Oasis. It does tie all ground pins together, but this should not be an issue for any prototyping.

The basic design that is used on the HP45 standalone controller in Oasis, with the 4017 and 4081 chips for the addresses and TLC59213 chips for the primitives works quite well. The mosfet on the ground of the HP45 is for some extra hardware protection (milliseconds of power on a single primitive will easily destroy it) and is mostly used to test the nozzles. This is the LM311 circuit.

Most fast microcontrollers can drive this circuit, though a fast microcontroller (100MHz+) and something 32 bits is nice. This circuit is designed around 5V tolerant chips, so I do not know if 3.3V only microcontrollers are possible.

Hope this helps give you a start.

[Catniped]

thanks, it sure is helpful

i read the page on the old hp45 controller, which says there needs to be 2 boards to breakout the printhead, i assume this is no longer correct with the v3? and i can just send this off to jlcpcb with the default settings (2 layers) and it should work? it seems a stm32 could work well for the mcu, so i might try using that with the breakout

also, does the connector you sell on tindie work with the standalone controller too or would i need to buy my own pogo pins to make that work?

[dragonator]

The old design board indeed required 2x a 2 layer board. This design has been replaced for quite a while though. The new design requires a basic 2 layer PCB to work.

For JLC (or any other board house) no exotic settings are required. The only thing that is helpful is gold plating. Most cheap PCB's are tin plated, and while this is fine for most boards, since springs contact the PCB, gold plating ensures good contact.

I do not have good photos of the breakout board, but it is the same size as the V3 controller, without the components and with 2 2x10 headers for connection (40 pins in total). I did search my workshop for half an hour since I was convinced I had a few boards left, but I only found my own assembled breakout, and no extra PCBs.

All designs including the V3 use the HP45 connector I sell on Tindie. When I was working on the HP45 this part could only be bought in bulk, so I started selling the excess.

[Catniped]

great, i ordered a connector from your tindie store but i think their payment gate fucked up, since i didnt get a security code or a confirmation about the payment. hope it goes well!!

[dragonator]

Don't worry, your order has been received. I will package and ship it tomorrow.

[Catniped]

amazing, thanks!

[Catniped]

got the connector and the pcbs today, i assembled the 2 (altho i just used the single big screw with the nut that the connector originally used, as the 2 screws youre actually supposed to attach the 2 together with didnt fit for some reason and the big screw + the alignment pins work fine), im printing the holder right now and will propably start trying to get the printhead working tomorrow