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SoliForum - 3D Printing Community → Hacks & Mods → Adding a second board
Hey everyone,
I have been thinking of adding a bunch of new sensors to my printer, and would like to use a second arduino to achieve this. Does anyone know if this is feasible? I am more than capable of doing the electronics and the firmware for the new board, but integrating it into the existing setup is where I am stuck at.
Cheers
I know that where you would normally plug in an sd card in the board, that is the i2c/spi interface - don't know how to speak i2c, but this would be the way to go for multiple boards.
So, your talking modified firmware on the solidoodle motor control board along with a board containing firmware to handle the sensors.
How many sensors are you talking about? 2 switches for each axis? A sensor to detect feed jams (like an encoder that grips the filament and counts forward / backward movement when steps occur...might be able to build that into the extruder idler for compactness)?
If you just want to deal with extra axis switches, you could just wire them up in parallel. When the switch is detected moving in one direction it means top, right, back position, etc.. and the other direction it means bottom, left, front position... Then no board is needed.
Still need to modify the firmware though.
I am more thinking of an auto levelling bed. I realise that this is a big project, but there is nothing quite like a challenge 
The way I am thinking of it working is this, and if anyone wants to give me a sanity check, fire away
Hardware modifications from stock would be as follows;
Glass bed
There would be a small stepper motor attached to each of the threads on the bottom of the bed (so three in total)
A probe of some sorts attached to the extruder which would be separate from the z height endstop
The way I would invision it working would be as follows;
Each of the stepper motors on the bed would wind themselves down a few millimeters (this makes sure the head would not bury itself into the bed)
The bed homes its Z axis with the existing endstop
The print head positions itself to the middle of the rear bed screw
The rear stepper motor would wind itself up until it hits the probe on the extruder and retracts itself a preset amount, which would give the appropriate height for the print
Repeat for the front left screw, followed by the right.
The whole reason this has come about is when i pull out and replace my piece of glass the bed is never flat after, and i need to redo my bed levelling. The benefits of having glass for me still far outweigh using just kapton on the normal bed, and so I am trying to resolve this final hurdle which is bugging me. I haven't seen anything like what I am thinking outside of big ass expensive machines so I am sure I will run into hurdles!
There would also be other benefits to adding a second board as well as this - more temp probes to monitor motors, a rotary encoder/other monitor on the filament to determine if the filament is being fed correctly, and if it has stripped or a jam has occurred it halts the machine, the possibilities are endless!
Thoughts?
btw, I am not fussed about modifying firmware, more than happy to play around with that. I guess I am more interested in if anyone has added multiple boards before, saves me reinventing the wheel.
Sounds ambitious and fun... I think the Azteeg 3 has up to five steppers and end stops which would help right off the bat. I'm in the middle of getting ready for that upgrade with dual Bowden extruders. I also think that board has capabilities for expansions which would be helpful. I'm surprised your bed needs releveled when replacing the glass, since I have yet to run into that problem yet.
The other problem might be adding weight to the bed if you're talking about hanging stepper motors underneath it. Even if they are small, three would have to add a decent bit of weight.
There is also the feature that is supposed to use the extra end stop to do adjustments for the bed level based on a probe at three points before the print. Still not sure if I have faith in this, but will try when I have time to install the board upgrade.
That post was the post that got me thinking about this. I know it is overly ambitious, but i figure it is worth a shot. I'll look into the azteeg more, see what is possible with that.
The added weight is the biggest thing at the back of my mind. I am on the lookout for lightweight motors, ive found a few, but nothing stands out.
You could use hacked microservos which are very cheap and extremely light... By the way, if you are going to add an extra board and continue to use glass for printing, it would be very easy to add a robotic arm that sweeps the piece off once the bed cools. I would be pretty interested in creating that mod and might investigate it.
If you don't feel like hacking a servo, they have pre hacked regular sized ones which are just a tiny bit more expensive and heavy but don't take any work.
Sounds to me like your bed leveling system could be fairly independent.
Consider: An extra sanguino has 4 motors it can control... you only need 3 to level the bed. The Sanguino has 3 additional switches, one of which is needed for your bed leveling system. That still leaves 2 axis switches, one motor controller, various other IO and probably lots of ram for other projects.
I can see it working where you send gcode to tell the Solidoodle to level the bed and then a new code that tells it to request the bed to be leveled.. Then the modified Solidoodle firmware sends the command to the leveler which goes through the preprogrammed steps and reports back that everything is done. Might need some polling code on the solidoodle side or something. I don't know what kind of timeout would be required to get the bed leveled... maybe sleep for a while first. Even if I2C doesn't work for some reason, you still have IO pins that can be used as serial ports if nothing else will work.
Sounds interesting.
Sounds ambitious and fun... I think the Azteeg 3 has up to five steppers and end stops which would help right off the bat. I'm in the middle of getting ready for that upgrade with dual Bowden extruders.
I have been thinking about this modification myself. I will be following your progress with interest.
Love the microservo idea, I have a fair few rc cars, but thought that I should be able to get a lighter normal stepper motor than a servo. I'll look into it more. I've done continuous rotation servo mods before on regular sized servos. I'm sure it won't be hard to set up.
Using a sanguino sounds like an interesting idea. Might start looking on eBay to see what I can find in the way of parts.
SoliForum - 3D Printing Community → Hacks & Mods → Adding a second board
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