21

Hey you wrote the firmware! Good job!

22

The um2go power supply isn’t up to moving all the steppers and supplying power to the nozzle heater and also supplying power to a 50W heated bed all at the same time. I did extensive testing of power usage on that thing - was amazed how much more power it uses if you fight the head movements, lol. So I modified the firmware slightly (20 lines of code?) to never turn on the bed heater and the nozzle heater at the same time. It works well - nozzle gets priority. I wrote this code for 3dsolex thinking they would sell thousands of these heated beds for um2go, lol. Instead I think probably less than 20 heated bed kits sold world wide.

23

That’s really niche. I mean how many UM2Gos were sold? If I were to get an UM as my first printer I would’ve went with the 2+ but since it’s my second printer the 2Go seemed viable. Oh well maybe UM will incorporate the heated bed into the “UM2Go+” like the Olsson block if there is a market for it. Cheers

24

Hey gr5org,

my UM2Go is on the way and I am convinced in ordering the HB kit. After reading through some material and the tutorial you wrote, I would like to ask what is the reason for a separate nozzle heater? Why doesn’t the original nozzle heater work with this set up?

Regards,

3DMuse

25

It’s all about power management. The power supply that comes with the um2go can’t run the servos, the nozzle heater, and the HB all at the same time. So instead of spending another $100 for a power supply I wrote code that never turns the nozzle and HB on at the same time with nozzle getting priority. But when printing ABS at 240C that meant the nozzle was on so much that the HB wasn’t getting it’s chance and I could barely keep the bed at 60C (fine for PLA). Increasing the wattage of the nozzle means the nozzle is off more of the time and so the HB can stay hot enough to print ABS (over 100C).

You could alternatively get a UM2 style power supply (around $90-$150) and leave the 25W heater in the um2go but I don’t know of any firmware for um2go with heated bed that doesn’t also include my power sharing algorithm so you’d have to make your own firmware. I try to ship 39W minimum with um2go kit.

26

So from my layman point of view let me explain again for my own understanding (correct me if wrong):

The original 25W heater “hogs” the power supply because it can’t draw that much current per second (or it is not designed to do so).

Whereas the >39W nozzle heater can draw more current per second, heating itself up quicker and giving the heated bed more time to draw current from the power supply.

And in the end it’s cheaper to upgrade the nozzle heater than the power supply system.

Thank you for your contribution for this. I am one of the few who needs it and luckily someone on the internet has come up with a solution! Cheers

27

Another way to think of it is this - I couldn’t come up with a safer solution in software to share the power. In theory I could let both heaters be on at the same time if I’m very very careful with overall power usage over the course of a second. But this software solution would be more complicated, harder to 100% test, and more likely to have a bug that cuts power half way through a long print! Plus I wouldn’t be 100% sure it would work with all um2go power supplies.

But the solution I came up with is easy to test (tested actual power usage by cutting open the power cable and inserting current measurement using oscilloscope).

28

Hey gr5,

the heated bed kit will be here on Saturday. Getting some stuff prepared for the installation. I have a question about the Tinkergnome Firmware perhaps you could help me. How do I load the firmware? Thanks for your help!

29

It’s best to contact me directly at thegr5store _at_ gmail.com.

The instructions and the firmware are here:

http://gr5.org/hb/

After downloading, connect USB between your computer and printer and using CURA choose “install custom firmware…” and select the downloaded hex file. It’s easy to go back to original firmware also in CURA.