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Ultimaker Original Acrylic Homemade Build - Thermocouple/Temp/Initial Setup

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Hello all, I've been gathering parts and building this Ultimaker Original since early December. I cut the acrylic parts on the laser at my college, and yes I regret making it out of acrylic but I did manage to assemble it and it looks sweet, just too bad I cant get it running. The major modifications it has is the e3d print head, and um2 feeder upgrade with the um1 adapter. When I connect to cura it recognizes the printer uploads new firmware, then when it goes to check nozzle temp it says the temp is 127, instead of something like 30. If I skip that step and go to check x, y, z axes it does not connect to printer. Just switched out the motherboard for one from folger tech, I bought the red thermocouple I pictured, thinking about buying the black one because that seems to be the issue, I have the genuine ultimaker original thermo sensor from fabrc8, looks like fabrc8 does not sell the thermocouple circuit board. Any thoughts would be nice I can provide more pics and info. Thank You








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Does anybody know if you can just wire the temp sensor directly to the board and cut out the thermocouple? I remember seeing something about just hooking up the sensor directly to the signal and ground connection points on the motherboard connection. The more research I do there more I see how much of a nightmare temp sensing issues are with the umo. I can't believe I'm about to buy a prusa i3 kit because I can't get this thing running, this is so lame. I'm so close, I literally feel like I just have to change the right thing in configurations.h and it would work. But I don't know what to change.

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In configurations.h it says 595 but it never says 597 as thermo option, this is my current firmware settings with a picture of the current board. Im sorry if this has already been answered 1000 times I've really been searching both the ultimaker and reprap forums. Printer connects to repetier-host but gives me the same 134 ish room temp reading and I cant move the steppers with the arrow controls.



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Ok guys thanks for walking me through that one, I got the temp sensor figured out, running a thermistor direct to the board I have room temp in cura. Now my question is, since I have the wrong 12v 40w for my e3d, can I order the dfrobot 19v 38w heater cartridge (will it be in the margin of error?) and is it a direct drop in replacement for the ultimaker original one?



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UMO heater hole is 4mm so make sure you buy a 4mm cartridge heater. These tend to cost more as it's hard to get much wattage in such a tiny package.

Wattage has purely to do with resistance and voltage. The formula is:

Wattage = Voltage squaed divided by resistance. Or W = v^2/R.

First calculate the R value - so for the 12V 40W that means it is r=v^2/W or 3.6 ohms. Wow. At 19V that's 100 Watts. That will melt itself in seconds even if it's inside an aluminum block. If you can get say a 9 ohm heater (40W at 19V or 16W at 12V) or a 14.4 ohm heater - or in between then that would work for a 19V system. Is your printer running off 19V?

There are many types of temp sensors: thermistors, thermocouples, PT100s. Most thermistors are the easiest to hook up to an arduino (because of the limited capabilites of arduino) but they usually are permanently wrecked if you go above around 150C to 200C so aren't appropriate for the head which typically prints at 200C to 240C. Thermocouples can handle much hotter than 250C so they are used for the UMO. The UMO+ uses PT100 which are made from platinum. Both thermocouples and PT100 need custom electronics. I don't know the diff between ad595 and ad597 but I'm guessing they are about the same. when using the thermocouples and the ad595 (or whatever it's called) the UMO expects exactly 5V=500C and 1V=100C and 0V=0C and so on linearly in between. without looking up the 2 parts I strongly suspect they both put out the same voltages for a given temperature.

Hooking anything directly to the temp sensor on UMO will either not give the right temp or will self destruct at temps of 200C.

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Checkout these great sites for building Marlin with various temp sensors:




The first one has many more options but is an older version of Marlin. But on the plus side you can do a diff on Configuartion.h and see what it did (it outputs configuartion.h in addition to the hex file).

The second one has a much newer version of Marlin but has fewer options. But it seems to have plenty of temp sensor options.

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