I designed this for the Rumba board because I'm upgrading my A8 for dual extruders. All parts can be purchased from Amazon, Aliexpress or ebay. This controller is purposely designed to be as cheap as possible while at the same time being as feature rich as any top of the line printer/controller. This design is capable of extruder temps over 400c, sensorless homing, auto X carriage alignment, full enclosure environment control (lights, chamber heater, ventilation, cooling (for PLA), and more), Unified Bed leveling, 4 material preheat options, full graphical display, physical buttons for process automation (probe offset routines, program start, pause, resume, nozzle clear, and more), AC or DC heated bed, multiple electrical cutoffs for thermal run away control, and more. Holes are located for M3 and M4 bolts. Tap the holes for M3 that line up with clearance holes sized for M3 (i.e. M4 wont fit through but M3 will). Alternatively tap holes that align with M4 through holes. Large holes in the back are for wire glands (size 19). The front panel has holes for buttons (Pi GPIO/Octopi enclosure plugin inputs for canned gcode). The side holes in front panel are for 20 mm switches (bed power and leds). The parts should fit on a stock A8 bed, but you may have to turn off brim. The lone larger hole is for USB bulkhead plug to rumba. The Pi and USB are routed external so that the USB cable can be unplugged from the PI and plugged into a computer for firmware upgrades. I included the freecad file for anyone who may want to modify the design.
Using a modified version of this PI case:
https://www.thingiverse.com/thing:922740
I will add the Marlin sketch, pi card image, wiring diagrams, and pics as the build progresses.
The access holes in the rear compartment fit the following glands:
https://www.amazon.com/gp/product/B0716XRWXM/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1
This bulkhead fitting is also used for a pi one wire buss to connect temp sensors and other 1 wire sensors for octopi enclosure plugin (https://plugins.octoprint.org/plugins/enclosure/):
https://www.amazon.com/gp/product/B00DV2BTGS/ref=ox_sc_saved_title_5?smid=A32IO94WFN2NEL&psc=1
The front panel left side hole is for usb to board:
https://www.amazon.com/gp/product/B01N6ERRX7/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
The front panel right side holes are for leds and bed power relays:
https://www.amazon.com/MeiBoAll-Round12V-Rocker-Switch-Waterproof/dp/B071W86XS7/ref=sr_1_3?keywords=20mm+SPST+Round+Rocker+Switch&qid=1559449082&s=electronics&sr=1-3
The front panel switch holes are for 12mm momentary buttons such as:
https://www.ebay.com/itm/Momentary-Waterproof-12mm-Round-Dash-LED-Light-Power-Push-Button-Switch-12V/142896183678?ssPageName=STRK%3AMEBIDX%3AIT&var=441878159880&_trksid=p2057872.m2749.l2649
Anet A8 Upgrade: https://www.thingiverse.com/thing:3854690
Using this carriage:
https://www.thingiverse.com/thing:3160905
The V2 front compartment replaces the front mosfet mounting pads with mounting holes to thread for a SSR to control AC bed heater (https://www.amazon.com/gp/product/B00RLMVBN0/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1) via ().
I ended up using a larger SSR (40amp for plenty of margin using cheaper SSR) so I designed a second enclosure strictly for the SSR and cooling fan. Links to the component are below. The four pin connector has the mosfet leds to the ssr and the power feeds for the 120mm fan.
https://www.amazon.com/gp/product/B00NWO68JI/ref=ox_sc_saved_title_1?smid=A2Y736KGZ14HTQ&psc=1
https://www.amazon.com/gp/product/B00P07G3VI/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B01HGHP3II/ref=ox_sc_saved_title_2?smid=A1PUUT3OIOMJ0X&psc=1
https://www.amazon.com/gp/product/B001K6XYWY/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
https://www.amazon.com/AMP-32VDC-250VAC-CIRCUIT-BREAKER/dp/B00OGL7GMO/ref=sr_1_1?keywords=8+amp+push+button+breaker&qid=1563122808&s=hi&sr=1-1
Using this power supply:
https://www.amazon.com/eTopxizu-Universal-Regulated-Switching-Computer/dp/B00D7CWSCG/ref=sr_1_3?crid=3O1F3DA4ZBENY&keywords=30a+12v+power+supply&qid=1559449659&s=electronics&sprefix=30a+12v+%2Celectronics%2C165&sr=1-3
Updated 03/25/2020: Upgraded X and Y to uStepper S-lite boards on motors for closed loop control. Working great so far.
Updated 12/09/2019: Uploaded Octopi image: https://filebin.net/k88vuvf34yk8b4ld
Pi passwd: raspberry
Octprint User: octoprint
password: octoprint
The enclosure plug in has been tested and works great. I added some gcode routines for the push buttons and for the Octoprint menu for filament load and unload. The routines handle heating the nozzles and feeding the filament in and out. You should measure your Bowden tube and adjust the routines for lengths. The temp sensors are on the 1-wire buss and you will need to update their serial numbers with what ever the SNs are for your sensors. Also be sure and set the output pin. If you have wired your printer per the schematics, you will need it to fire the relay to supply heater power. This design has multiple thermal runaway redundancy so even if the fets fail closed and/or the controller fails to shutdown power relay the pi can drop the supply voltage relay.
Updated 11/08/2019: Uploaded the Marlin sketch. Everything is working great and have been printing on this build for a few weeks. I tried for a couple of weeks to get TMC2208 drivers to work on the extruders with linear advance but long story short they are not a good fit for it. Ended up using 8825s on the extruders with linear advance and it turned out great. The OctoPrint image is almost ready, it is working good with the enclosure plug in. I have programmed up the hardware buttons and created a few menu buttons to include filament load and unload for a few materials. There are also temp sensors monitoring stepper temps. I'll post the PI image in the next few weeks.
Updated 10/17/2019: Everything is up and running, have finished a few test prints with each nozzle but no dual nozzle prints yet, still tuning and working on a couple things first. The 500W heated bed is sick, it has no problem reaching 150C and hits 110 faster than the nozzles. Using PID control on the bed also. Linear advance has been a pain with the TMC2208 drivers for the extruders. Running them in standalone and they do not like linear advance. I have ordered some DRV8825s to see if I can get linear advance working as advertised. Other than that everything is working awesome. All canned routines and GPIO work, filament load and unload of different materials, Sensorless homing and X axis carriage alignment all work great. Will be posting the Marlin Sketch and Pi image soon.
Updated 09/10/2019:
Wiring of printer is coming along nice. X Y Z and extruders are moving, but have to calibrate steps/mm and sensorless homing. BLtouch and Reprapdiscount full graphic controller are also working well. The 4 material preheat options are also doing great. I switched from GBL to Bileaner bed leveling so I could add in the linear advance option in Marlin. I will be out of hand for a couple weeks so will be awhile before posting more progress. Once I get all options working and calibrated I will post Marlin sketch and Pi image. I will also add the printer mods and enclosure design in another design linked here. Enclosure and printer will be designed to control the temp and allow cool air to the extruder heat sink.
Updated 09/01/2019:
Added a cut to the front bay top to clear front panel attachment screws.
Updated 08/21/2019:
Up loaded cura settings for Hatchbox ABS, Hatchbox PLA, and Priline CFPC used to make this and printer parts. These settings are for stock A8 direct drive. These settings worked good for my setup but may need adjusting for each individual machine. No guarantee they will work for others. Used a 0.4 nozzle for all, used Micro Swiss all metal brake and hardened nozzle with CFPC. Printed the mid plate out of ABS incase the power supply gets warm, don't want PLA sagging down on parts below. The rest of the case was printed with PLA. Upgraded printer parts are ABS and CFPC to handle the enclosure temps that will be coming with the enclosure and for additional strength.
Updated 08/20/2019:
Added notch to rear compartment top to clear cable gland nuts. Have most of the wiring done and the Marlin sketch early testing is looking good. 4 material preheat in the marlin menu is working, drives tested, kill relay, and schematic is finished. Octopi Enclosure app is up and running with one wire bus temp sensors and thermal relay working. Updated all files with schematics are loaded. Will post additional updates as build progresses.
Updated 07/25/2019:
The 3v relays to control the power contactors are not compatible with the 5v output from the Rumba suicide pin so incorporated the following voltage regulator to step the voltage down. NOTE: (08/21/2019) relays work with 5V and a 20ohm resistor in series.
https://www.amazon.com/gp/product/B01N1I1LXH/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
Added mounting pad for thermo couple amps.
https://www.aliexpress.com/item/32804762614.html?spm=2114.search0104.3.1.573448a5C5AIkH&ws_ab_test=searchweb0_0%2Csearchweb201602_10_10065_10130_10068_10547_319_10546_317_10548_10545_10696_10084_453_454_10083_10618_10307_537_536_10059_10884_10887_321_322_10103%2Csearchweb201603_53%2CppcSwitch_0&algo_expid=f679531f-979d-455f-a9cc-5ee65ff5ff3f-0&algo_pvid=f679531f-979d-455f-a9cc-5ee65ff5ff3f&transAbTest=ae803_5
Updated 06/27/2019:
Added cutouts in control panel and front cargo bay to better clear display connectors.
Updated 06/24/2019:
Added stop button for reprap full graphic display stop momentary button. Added stl and updated freecad file. Also added clearance for display on front panel. I have printed and assembled the enclosure. Most components are mounted and and wiring is going well. I added mounting holes to the bottom of the power supply mid bracket for four relays. Two high amp relays (one for end supply voltage and one for SSR AC supply voltage i.e. heated bed power). The control relays are fired by the PI GPIO (octoprint enclosure app temp monitor) and the RUMBA+ (Marlin suicide pin) respectively. The two control relays supply coil voltage to the larger relays. This provides an extra fail safe for thermal runaway due to a failed mosfet or ssr. Have the Marlin Sketch looking well and compiling so hope to start initial testing soon. Going to add type K thermocouples for ends. The 40 amp SSR will not fit in the enclosure so I'll be adding a sub enclosure soon. I will also be designing a plate to mount in the third mosfet location for the thermocouple amps. Using AD8495 thermocouple amps such as:
https://www.aliexpress.com/item/32804762614.html?spm=a2g0s.9042311.0.0.22f14c4dTJy7DU
Update 06/01/2019:
Fixed corrupt rear compartment stl and model. Updated mid power supply bracket. Added v2 front compartment for SSR mount. Added V2 front panel. Added hole in front compartment for Rumba usb cable to be able to plug in while mounted.
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