RUG/Pennsylvania/State College/Electronics

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This section is for info on the electronics we're using with RepRap. This mainly relates to our control boards, but may include supporting electronics, like the Thermocouple adapter boards we're using with RAMPS.

Parts Inventory A list of electronics parts we're using-- or intended to.


RAMPS Electronics

The majority of our printers are Open Hybrid Mendels, most of which are running RAMPS 1.4 electronics. The only printers not running and not in progress of getting a RAMPS 1.4 are the White printer and Big Red. The advantage these have over the RAMBO is that they are smaller and easier to fix if broken. It has replaceable driver boards that are easy to swap out for new ones if they are broken.

Thermocouple Adapter Boards

Instead of using thermistors for temperature monitoring, we currently use thermocouple adapter boards based on Analog Devices's AD595 IC. We connect the thermocouple board to pins 1,2,3 of AUX1 (5V, GND, and A3), and change TEMP_0_PIN to 3. Check the flashing tutorial for details.

We have found that connecting the AD595 backwards results in the destruction of the IC. To avoid this, we use keyed connectors (digikey 487526-2-ND and A28527-ND). The connectors have a slot/key that divides one pin from the others; we use this pin as 5V and the others for signal and ground (which swap pins from one side of the cable to the other). This allows the cable to be reversible.


Two our printers are using RAMBo electronics. The White printer and Big Red. RAMBo is an integrated Atmel ATmega 2560 micro-controller and RAMPS board. It also contains the the stepper controller boards on device instead of having them plug in. The benefit of using RAMBo is that it is slightly cheaper to have everything on device. The downside is that if anything breaks you will need to get a whole new board (or very carefully use a hot air rework station to remove the smd chips) since everything is surface mount. In addition, one must send g-code to set the motor current since there is a digipot instead of real potentiometers. Compared to the RAMPS the RAMBo has more inputs, but if one thing breaks you may have to replace the whole board. More info (especially on the firmware) can be found here:

Known Issue

Currently, M907 (set stepper motor current) cannot be used to change the extruder motor current (M907 E$ does nothing). As a work around, use M907 S$ to change the current of all stepper motors, including the extruder motor, to some value (represented by $) then change each other motor individually by using M907 X$ Y$ Z$.

Enter these commands at the start:

M907 S70 ;sets all motor current levels to 70

M907 Z100 ;sets the z motor current level to 100

Hot Tips

Here is an older list of compiled information about hot tips for extruding. Information includes electronics used, number of thermocouples and operating temperatures we have found effective.

More recently this page has given more accurate information on tip construction, tip models, and their overall design, as well as details on the Bowden Extruder model that is becoming more popular for printers. This page also provides detailed instructions on the manufacturing of the metal bodies than plates that are used for the newer hot tips.

ATX PSU Dev Board

We currently have 2 ATX PSU Dev Boards. One is being used with a RAMBO on the White printer. The other is not being used for any printer in general. Using these we are able to power 2 printers at the same time or one printer with a heated bed. These boards also put put voltages lower than the 12v required to run a RAMBO or a RAMPS. In future designs these lower voltage outputs can possibly power peripherals other people design.

General Electronic Components

Old Information


For a time we used TechZone Monotronics on several of our printers. Details are here: /Monotronics

Generation 3 Electronics

We currently have two Mendels on site (Alpha and Beta), created from Techzone kits. They use the Gen 3 TechZone Remix hardware, but we use an extra Stepper Driver board instead of running the extruder from the Extruder Controller.

Comparison of Electronics

On this page there is a comparison of Sanguinololu, Generation 3, Generation 7 and RAMPS Electronics

Once we decided that RAMPS seemed to be one of the best choices for electronics on the Prusa-style RepRaps we were building, we compiled a list of prices from various possible sources: RAMPS

Building Custom Motherboard

One of the goals of our program is gaining the ability to produce RepRaps to distribute to other groups at the university. To do this we need to bring build costs as low as possible. To this end, we are researching alternate electronics systems in hopes of finding one which we can produce ourselves, without needing to purchase kits or completed boards from third parties. This section serves as an index for that research.

  • Requirements
  • Would be nice
    • High step count
    • SD Card support
    • Control panel (computerless)

.c Code Download

File:Marlin-Marlin v1 Mendel's .c code

Page List

Removed because it was causing server error messages: <splist/> In the meantime, see here: [1].