Monoprice Delta Upgrade Path

Status: April 3. 2026 - The printer has been working well on the base. I'm working on pictures of the wiring.

Note: This project is very much a work in progress.  Models will change but I'm looking for feedback on the model, consideration for other boards. The board I'm using I just happened to have on hand and is overkill for this printer. Keep on the lookout for updates.

Overview

The Monoprice Delta is a cool printer. Unfortunately, the main board and power supply leave much to be desired. This project aims to provide an upgrade path which aims to preserve the awesomeness of this tiny Delta printer while providing upgrades to some key components and open the possibility of this printer printing well with filaments other than PLA.

PROCEED AT YOUR OWN RISK!! YOU ARE RESPONSIBLE FOR THE IMPLEMENATION OF THIS. DON'T BLINDLY TRUST MY KLIPPER CONFIG.

The design decisions I made are right for my scenario and goals.  Feel free to deviate.  I'd love to hear what you do!

My Goals

There is a lot I like about this printer:

• It heats up FAST

• It doesn't heat up my office like my full-size printers would

• It is easy to enclose and heat the chamber

• Power draw is reasonably low

• It is quiet

Is it a speed demon? No, but it's also not prohibitively slow.  After all it's only a 120mm diameter by 120mm tall build volume so it doesn't have to be blazing fast.

Parts

Parts you'll need:

• 500G of PLA

• BTT Octopus v1.1 

• 24V Power Supply

• 24V hot end cartridge for a MK3 hotend

• Dupont Connectors and crimper

• 12V buck convertor for the heated bed. I went with a 30A out of an abundance of caution. I intend to measure the current draw to provide a better sizing.

• Some mini-computer to run Klipper

• The integrated LCD and controls will no longer function. I'm working on a solution for that, but KlipperScreen provides some simple options.

• 4010 24V or 12V fan depending on what you have on hand.  The Octopus can handle either. 

Note: As an Amazon Associate, I may earn a commission for products purchased from the links in this description.

Wiring

Some rewiring is necessary, but the changes are fairly simple:

• Stepper Motors: At least in my case, the stepper motors simply plugged in to the board.  No changes needed.

• End stop optical switches: Aside from having to lengthen one of the cables and repinning the connectors, they also plug directly in to the board.  You may need to figure out the correct wiring based on your specific model.  I recommend removing one of the optical end stops and investigating the wiring yourself.  That's what I ended up doing.  I've heard rumor that there is some variance in wire colors and I can tell you, the colors I encountered were not logical.

• Bed switches: All switches are wired in parallel to one input on the board and are recrimped in a Dupont connector.  These switches seem to work quite well for Delta Calibration in my experience. I was ready to try other options but I don't think it is needed.

• Hot end: The stock hot end runs on 12V, which is fine, but the Octopus only supports 24V cartridges and honestly, it's a great upgrade anyway.

• Heated bed: The heated bed seems to be quite adequate for the printer, but it runs on 12V.  You can provide 12V however you deem fit.  For me, I already had a 12V buck converter, so I used that with my 24V power supply.

• Thermocouples: Plugged directly in to the board without issue

• The 4010 can be attached to either the front or the back grill on the printed base.  Use M3s to bolt the fan.

Having, or making Dupont extension cables may be necessary.  I made 4" extension cables for all the cables I attached to the motherboard. It makes opening and closing the printer much easier.  Additionally, some cables may not be long enough. Here are the cables you'll need:

• 4x - 4 pin stepper motor extension cables

• 4x - 3 pin extension cables for the optical end stops and bed switches

• 4x - 2 pin extension cables for the thermocouples, heat break fan, and chassis fan

Klipper Configuration

Current Klipper config:

[include mainsail.cfg]
[mcu]
serial: /dev/serial/by-id/usb-Klipper_stm32f446xx_0C0031001850535556323420-if00

[include timelapse.cfg]

[exclude_object]

[gcode_arcs]
resolution: 0.1

[printer]
kinematics: delta
max_velocity: 150
max_accel: 1200
max_z_velocity: 100
# minimum_z_position is negative to allow delta calibration to work
minimum_z_position: -10.0
#delta_radius: 63.00
# Some users report better success using the following value for arm_length:
#delta_radius: 62.70

[force_move]
enable_force_move: True

[virtual_sdcard]
path: /home/rvanderp/printer_data/gcodes
on_error_gcode: CANCEL_PRINT

# This file contains common pin mappings for the BigTreeTech Octopus
# Pro v1.1 board.

# Driver0
[stepper_a]
step_pin: PF13
dir_pin: !PF12
enable_pin: !PF14
microsteps: 16
homing_speed: 50
rotation_distance: 27.8208
endstop_pin: PG6
#position_endstop: 125.00
#arm_length: 120.8

# Driver1
[stepper_b]
step_pin: PG0
dir_pin: !PG1
enable_pin: !PF15
microsteps: 16
rotation_distance:27.8208
endstop_pin: PG9
#position_endstop: 125
homing_speed: 50
#arm_length: 120.8

# Driver2
[stepper_c]
step_pin: PF11
dir_pin: !PG3
enable_pin: !PG5
microsteps: 16
rotation_distance: 27.8208
endstop_pin: PG10
#position_endstop: 125
#arm_length: 120.8

# Driver4
[extruder]
step_pin: PG4
dir_pin: PC1
enable_pin: !PA0
#endstop_pin: PG11
microsteps: 16
rotation_distance: 16.9175
nozzle_diameter: 0.400
filament_diameter: 1.750
heater_pin: PA2 # HE0
sensor_pin: PF3 # T0
sensor_type: EPCOS 100K B57560G104F
#control: pid
#pid_Kp: 22.2
#pid_Ki: 1.08
#pid_Kd: 114
pressure_advance: 0.45
min_temp: 0
max_temp: 250


[heater_bed]
heater_pin: PA1
sensor_pin: PF4 # TB
sensor_type: ATC Semitec 104GT-2
min_temp: 0
max_temp: 75

[controller_fan controller_fan]
pin: PE5
stepper: stepper_a, stepper_b, stepper_c, extruder
fan_speed: 1.0
idle_timeout: 30 # keeps running 30s after steppers disable
idle_speed: 0.3 # slows to 30% instead of shutting off
shutdown_speed: 0

[heater_fan hotend_fan]
pin: PA8 # your actual fan pin
heater: extruder
heater_temp: 50.0 # turns on when hotend exceeds 50°C

########################################
# TMC2209 configuration
########################################

[tmc2209 stepper_a]
uart_pin: PC4
#diag_pin: PG6
run_current: 0.400
stealthchop_threshold: 999999

[tmc2209 stepper_b]
uart_pin: PD11
#diag_pin: PG9
run_current: 0.400
stealthchop_threshold: 999999

[tmc2209 stepper_c]
uart_pin: PC6
#diag_pin: PG10
run_current: 0.4
stealthchop_threshold: 999999


[tmc2209 extruder]
uart_pin: PC7
run_current: 0.400
stealthchop_threshold: 999999

[probe]
pin: ^!PG11 # your probe pin on Octopus
#z_offset: 0 # set via PROBE_CALIBRATE
speed: 2.0 # slower is more reliable for piezo
samples: 3
sample_retract_dist: 2.0
samples_tolerance: 0.20
samples_result: median # use median of samples to reject outliers

[delta_calibrate]
radius: 50 # probe radius - keep inside bed edge
speed: 50
horizontal_move_z: 5

[bed_mesh]
speed: 50
horizontal_move_z: 5
mesh_radius: 50 # Mini Delta bed is small, adjust accordingly
mesh_origin: 0, 0
round_probe_count: 5
algorithm: bicubic

[homing_override]
axes: xyz
gcode:
G28 A B C # home all three towers
G1 Z5 F1200 # lift slightly
G1 X0 Y0 F3000 # move to center
;PROBE # probe bed center

[board_pins]
aliases:
# EXP1 header
EXP1_1=PE8, EXP1_2=PE7,
EXP1_3=PE9, EXP1_4=PE10,
EXP1_5=PE12, EXP1_6=PE13, # Slot in the socket on this side
EXP1_7=PE14, EXP1_8=PE15,
EXP1_9=<GND>, EXP1_10=<5V>,

# EXP2 header
EXP2_1=PA6, EXP2_2=PA5,
EXP2_3=PB1, EXP2_4=PA4,
EXP2_5=PB2, EXP2_6=PA7, # Slot in the socket on this side
EXP2_7=PC15, EXP2_8=<RST>,
EXP2_9=<GND>, EXP2_10=PC5

# See the sample-lcd.cfg file for definitions of common LCD displays.

# A [probe] section can be defined instead with a pin: setting identical
# to the sensor_pin: for a bltouch
#[bltouch]
#sensor_pin: PB7
#control_pin: PB6
#z_offset: 0

#[neopixel my_neopixel]
#pin: PB10

#*# <---------------------- SAVE_CONFIG ---------------------->
#*# DO NOT EDIT THIS BLOCK OR BELOW. The contents are auto-generated.
#*#
#*# [heater_bed]
#*# control = pid
#*# pid_kp = 65.424
#*# pid_ki = 5.192
#*# pid_kd = 206.085
#*#
#*# [extruder]
#*# control = pid
#*# pid_kp = 17.806
#*# pid_ki = 0.698
#*# pid_kd = 113.511
#*#
#*# [printer]
#*# delta_radius = 62.502593
#*#
#*# [stepper_a]
#*# angle = 211.210415
#*# arm_length = 120.800000
#*# position_endstop = 126.231
#*#
#*# [stepper_b]
#*# angle = 329.629689
#*# arm_length = 120.800000
#*# position_endstop = 123.255
#*#
#*# [stepper_c]
#*# angle = 90.000000
#*# arm_length = 120.800000
#*# position_endstop = 123.980
#*#
#*# [bed_mesh default]
#*# version = 1
#*# points =
#*# 0.010877, 0.010877, 0.010877, 0.010877, 0.010877
#*# 0.536370, 0.536370, 0.262796, 0.306239, 0.306239
#*# 0.482834, 0.391924, 0.375887, 0.512029, 0.625312
#*# 0.428323, 0.428323, 0.421689, 0.313425, 0.313425
#*# 0.404878, 0.404878, 0.404878, 0.404878, 0.404878
#*# x_count = 5
#*# y_count = 5
#*# mesh_x_pps = 2
#*# mesh_y_pps = 2
#*# algo = bicubic
#*# tension = 0.2
#*# min_x = -50.0
#*# max_x = 50.0
#*# min_y = -50.0
#*# max_y = 50.0
#*#
#*# [probe]
#*# z_offset = -0.365
#*#
#*# [delta_calibrate]
#*# height0 = -0.365
#*# height0_pos = 14498.000,14187.000,14254.000
#*# height1 = -0.365
#*# height1_pos = 17979.000,17574.000,12355.000
#*# height2 = -0.365
#*# height2_pos = 14144.000,19749.000,13837.000
#*# height3 = -0.365
#*# height3_pos = 12692.000,17006.000,17074.000
#*# height4 = -0.365
#*# height4_pos = 13934.000,13670.000,17946.000
#*# height5 = -0.365
#*# height5_pos = 16724.000,12467.000,16546.000
#*# height6 = -0.365
#*# height6_pos = 19040.000,13705.000,13771.000