Control RapRap from an Arduino UNO

I have build a little control panel with an LCD display that I would like to connect to my RepRapPro.

Can I connect the Arduino UNO's USB to the Melzi USB?

Firstly will it work, and if so does a cable or adapter exist to connect USB B to USB Mini B?

Steve

USB is assymetric; computers usually have USB hosts, the melzi and arduino are both clients..(or master/slave.. terminology) So dont see it happening through USB. More likely via a serial connection on one of the pins the melzi exposes. However, havent found any easy source on how to use it.

I think 'in a perfect world' it'd be possible to use some of those pins to get a serial/i2c connection, and tell the machine stuff to do,(and have an arduino lib to make it easy, there are unicorns in this world too) including passing on messages to the USB the melzi(or other reprap electronics) is connected too. (And the USB can also pass messages on to the serial-hangers) I suppose there would also be a command 'tell me where you are in a file'. I do not hope how close that is, maybe someone here can tell us about the pins. It is open source of course, you can go look at the stuff and figure it out if you have the skills.

Alternatively raspberry pis do have USB hosts. I have one, if i get ssh going think i'll use that to command it. Wirelessly if I have a USB wireless stick.(have two really old ones and both worked, apparently it all compiles to arm with relatively little issue) Of course i might also use this raspberry pi for other things aswel. Dont think serving up the gcode is all that much work for it.

I suppose with the control panel and reprap attached you might not have room for the wireless USB; just two USB ports.. Posible solutions: a wired connection, a usb-hub, and you could also try running the LCD straight from the RPi..(Though the RPi isnt 5V-tolerant)

Thanks, that's a very comprehensive answer.

I'm glad that you understood the question I was asking. I thought I should be able to use the communication pins on the melzi but I couldn't find any details on how to do it.

What about if I add a USB host shield to my Arduino UNO, such as this

> Thanks, that's a very comprehensive answer.
Bit of a compulsion to type sometimes :p FTR I dont actually have much experience making electronics.(though i know a bit) You could try asking elsewhere too, it seems likely you might have missed people who know more about it? For instance maybe on google+, r/reprap, marlins issues. (well melzi here, but probably development on the other one)

I didnt know about USB-hosts existing for arduino like that. It is a bit of a roundabout, but i dont see any reason why it wouldnt work. The host has to get the same baud rate as the client, i think.(250000 for me) Seems likely it can do whatever needed baud rate. (Aside: wonder if it is possible to make a microcontroller scan the different baud rates until it succeeds)

Note the Ultimaker has a LCD interface, they exist for RAMPS, at least. Sorry for forgetting it earlier...(it might not be relevant, of course)

Suppose you have seen this reprap wiki page already? I think the JY-MCU bluetooth thing send talks the serial normally via the USB directly. So maybe the arduino uno can talk there too. They're not connected to the headers according to the picture, and maybe the i2c you mention in the other thread has different advantages.