Itty Bitty Double Extruder

[clough42]

The short answer, if you're using the Pololu 1209 motor is that I have them wired blue-red-green-black. You may have to flip the connector if the motor turns the wrong way.

In general, a four-lead stepper motor has two coils. You can use an ohmmeter or continuity tester to figure out which wires are connected to the same coil. On the Pololu motor, you'll find that the blue and red wires are connected to one coil and the black and green wires are connected to the other

You can also figure it out with no tools. If you connect two wires from the same coil together, the motor will get harder to turn by hand and you will know you've found a pair.

Once you figure out the coils, just connect the wires in order, the two wires from one coil, followed by the two wires from the other cool. Order doesn't matter, except to change the motor direction. If your motor turns the wrong way, just turn the whole connector around on the board.

Pro tip: if you need to extend your motor wires, Makerfarm has motor extensions really cheap. As in cheap enough that I buy ten or twenty every time I place an order, just for the wire.

Extruder question -

I have both extruders wired as follows BLK->1A, GRN->1B, RED->2A, BLU->2B. This matches what Polulo recommends - Coil A=BLK, Coil C=GRN, Coil B=RED, Coil D=BLU. Neither of the extruders will move. If I plug my old NEMA17 extruder in it works fine. Continuity test indicates that the wiring is correct. Any suggestions?

I quoted my previous comment on motor wiring above. Black-Green-Red-Blue should be right.

You should be able to resist the motor or turn it by hand when it's parked, but it should be way harder than when it's disconnected. You can try shorting black and green together and trying to turn by hand. Same with red and blue. In either case, it should get harder to turn.

If you can plug your old extruder into the same port and it turns, but the 1209 motors won't turn--even without a belt on--it seems like it would have to be the motor or the wiring. I can't imagine what else could be causing it.

Just to confirm: You have two 1209 motors, and they're behaving the same?

Next step might be to upload photos or video of your setup to see if anyone else notices anything.

Are you near anyone else who could lend you parts for testing? Do you have a RAMPS board or know someone with one who would let you plug in a motor to see how it turns? Heck, if you want to send me a motor, I'll be happy to test it for you. This stuff is tough to do by yourself.

[kd7eir]

Connecting blk/grn and red/blu together does result in the motor being harder to turn. Tomorrow I will remove the belt and see if that changes anything. The motors are very easy to turn with the belt in place, so I don't think that is a cause, but I need to test everything. I can buy a new RAMPS board if necessary, but I think that is not necessary since the original extruder motor works just fine.

[Multiplxd]

Just wanted to throw my hat in the ring, I've finally got all the parts on hand and I should hopefully be putting together my itty bitty this weekend. Thank you Clough for putting together what is a much more affordable dual extruder than just about anything else out there that I've seen.

When I bought this machine back in September I grabbed a RRD fan extender at the same time with the hopes of upgrading to dual extrusion in the future. It worked for awhile, however there seemed to be a short of some kind and the board stopped working. While I was contemplating ordering another for this kit, I like many others here was a bit bitter that I lost two of the servo pins and ended up spending the evening last night designing a MOSFET breakout board that connects to the servo pins via servo cables and provides you with up to 4 MOSFET channels, which also includes a 40mm fan mount for cooling, all of course without blocking any of the servo ports. I'll be ordering the parts this weekend will report back with how it worked out if you guys are interested.

[kd7eir]

I plugged the extruder motors into the Z motor connectors and they worked perfectly. Replaced the stepper driver and the extruder motors still did not work plugged into the E0/E1 connectors. I ordered a new Mega and RAMPS board. I will install them tomorrow and hopefully all will be well.

[Poindexter]

Just wanted to throw my hat in the ring, I've finally got all the parts on hand and I should hopefully be putting together my itty bitty this weekend. Thank you Clough for putting together what is a much more affordable dual extruder than just about anything else out there that I've seen.

When I bought this machine back in September I grabbed a RRD fan extender at the same time with the hopes of upgrading to dual extrusion in the future. It worked for awhile, however there seemed to be a short of some kind and the board stopped working. While I was contemplating ordering another for this kit, I like many others here was a bit bitter that I lost two of the servo pins and ended up spending the evening last night designing a MOSFET breakout board that connects to the servo pins via servo cables and provides you with up to 4 MOSFET channels, which also includes a 40mm fan mount for cooling, all of course without blocking any of the servo ports. I'll be ordering the parts this weekend will report back with how it worked out if you guys are interested.

There is a work-around to access the the two servo pins that are blocked by the fan extender. You can solder wires to the solder points on the fan extender board above the pins that aren't being used. If you use this method you will have to jumper the 5V pin below to send power to those pins. I used this method to power my servo when I couldn't figure out how to power it off of the AUX-2 section. Since you already designed an alternative this may not be of much help to you but hopefully someone else might find it handy. BTW, work-around courtesy C42.

[kd7eir]

OK, I got my new Mega and RAMPS board today. Exact same behavior - extruders work if plugged into X, Y, or Z drivers, NOTHING works when plugged into either of the extruder drivers. I have switched out all stepper drivers, including exchanging the working X, Y, and Z drivers with the extruder position. I have reloaded Marlin several times to no avail. I have even reloaded the original MakerFarm Marlin just to see if I could get one extruder to work - nothing. I am now completely stumped.

[sniffle]

Are the correct pins called in pins.h for the extruders? Dunno shot in the dark throwing my .02 in to try and help...

[clough42]

OK, I got my new Mega and RAMPS board today. Exact same behavior - extruders work if plugged into X, Y, or Z drivers, NOTHING works when plugged into either of the extruder drivers. I have switched out all stepper drivers, including exchanging the working X, Y, and Z drivers with the extruder position. I have reloaded Marlin several times to no avail. I have even reloaded the original MakerFarm Marlin just to see if I could get one extruder to work - nothing. I am now completely stumped.

Same jumpers on the board under the drivers?

Change the text in Configuration.h that shows on the LCD just to be absolutely sure you're getting new firmware loaded.

[kd7eir]

Same jumpers on the board under the drivers?

Change the text in Configuration.h that shows on the LCD just to be absolutely sure you're getting new firmware loaded.

Embarrassment time. The extruder will not turn unless the hot end is at a minimum temperature. I was testing piecemeal, without the hot end preheated. Thank you to everyone that offered their help - sorry for the red herring.

[AbuMaia]

At least you now have a backup RAMPS.