Hi all, I'm doing a temperature mod for my UP! Mini 3d-printer which involves fooling the cpu into thinking the extruder is warmer than it really is by modifying the resistance from the temperature gauge with a resistor/potentiometer. This is commonly done with these printers but I want to take the mod a step further and put the potentiometer on a perfboard with a display and an Arduino or Attiny which converts the resistance trough the potentiometer to display degrees Celsius trough a calculation.
For the measuring part I think I should follow this guide How to Build an Ohmmeter Using an Arduino , but can I put 2 circuits trough the pot, 1 being the printer for altering resistance and 2 being the Arduino to measure the resistance? My limited knowledge of circuits tells me this would work as long as they don't have a common ground or positive, right? Thanks in advance!
The simplest way of doing this is to use a double gang pot (used in stereo systems) and use one for control and the other for display.
Something like one of these Search | Maplin | The Electronics Specialist
jackrae:
The simplest way of doing this is to use a double gang pot (used in stereo systems) and use one for control and the other for display.Something like one of these Search | Maplin Electronics
Awesome, thanks!
Damn seems like they don't exist in 100 ohm...
but can I put 2 circuits trough the pot, 1 being the printer for altering resistance and 2 being the Arduino to measure the resistance? My limited knowledge of circuits tells me this would work as long as they don't have a common ground or positive, right?
No.
stormychel:
Damn seems like they don't exist in 100 ohm...
Why does it have to be 100R?
Grumpy_Mike:
but can I put 2 circuits trough the pot, 1 being the printer for altering resistance and 2 being the Arduino to measure the resistance? My limited knowledge of circuits tells me this would work as long as they don't have a common ground or positive, right?
No.
stormychel:
Damn seems like they don't exist in 100 ohm...Why does it have to be 100R?
The printer cpu measures the heat inn the nozzle by the amount of resistance the head has, for the normal temperature of 260c this is +-900 ohm. Increasing this by 12 ohm makes the cpu think the temperature is 192, so it will stop heating until temp is back to 260. Actually this brings temp down to 228c, the ideal temp for the filament I wish to use. That is the normal mod, but being able to choose from 0 to 100 ohms of extra resistance gives me temperature control from 0 to 260c...
The moral is closed-source 3D printers are false economy...
Bourns (amongst others) do 100 ohm wire-wound dual pots but they will no doubt be expensive.
However there is a cheap way.
Simply get hold of a couple of 100ohm linear slider pots, mount them side by side and couple their knob levers together.
MarkT:
The moral is closed-source 3D printers are false economy...
True ? But it's a challenge to get the most out of this cheap printer?
jackrae:
Bourns (amongst others) do 100 ohm wire-wound dual pots but they will no doubt be expensive.However there is a cheap way.
Simply get hold of a couple of 100ohm linear slider pots, mount them side by side and couple their knob levers together.
Good idea, will solve it that way? thanks!