Alternative Electronics

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You might also want to look at Alt Select Electronics. Perhaps some or all of that page should be merged into this page. (Discuss)
This page has been flagged as containing duplicate material that Electronics Variations also attempts to cover.
These pages should be merged such that both pages do not attempt to cover the duplicate topics.
This page has been flagged as containing duplicate material that "Official" Electronics also attempts to cover.
These pages should be merged such that both pages do not attempt to cover the duplicate topics.

The page RepRapElectronics has a good high-level description of what the electronics do and how they connect to the rest of the system. The standard, well-tested RepRap electronics are described at circuit board construction. Various ways of mounting and cooling RepRap electronics (whether standard or nonstandard) are described at Electronics Improvements.

Many people have come up with ideas for improving on those electronics. We list and compare and contrast some of those ideas here.

Feel free to download the current version of the RepRap electronics on SourceForge and make improvements, rather than starting from scratch.

If you want to know about the weird naming convention/s being used here, including the strange ( and broken) "Gen X" nomenclature, please see Electronics_Variations.

Overview Electronics Pages


Recommended

Experimental, and New ( your new design goes here till at least independently reviewed )

  • Gen_L_Electronics -- Designed to be very low cost, easy to assemble, but tethered to a computer via USB
  • HBox_RepRap_Electronics -- Cutting edge electronics soon going on sale
  • Generation 7 Electronics -- easy single board solution, to be build with a RepRap
  • Generation 6 Electronics -- easy plug n play electronics, single board solution
  • Sanguinololu Combining the Pololus and a Sanguino controller into a single, tiny, low cost board.
  • StepStick A low-cost drop in replacement for Pololus motor drivers - A4983/A4988
  • Repic -- "as simple as possible" all-in-one electronics based on PIC18F4550 or PIC24, on single-sided, through-hole PCB.

Deprecated and Older Electronics pages

DIY Circuit Board Manufacturing

  • According to some estimates, the vast majority of RepRap and RepStrap machines use one of the above custom PCBs specifically designed for RepRap and fabbed by a commercial PCB fabricator. Mendel Buyers Guide and PartsSupplies lists some of the places selling such PCBs, either the empty PCB or the assembled PCBA with all the parts already soldered on.

Theoretical

Various pie-in-the-sky ideas ...

  • One of the more fascinating ideas is to use the RepRap itself to help manufacture the next generation of electronics. We talk more about that idea on the Automated Circuitry Making page.
  • Is it possible to build a RepRap that, instead of using the standard Stepper Motor Driver 2.3 boards, instead used some other stepper motor driver boards? perhaps the open-source OpenStepper boards ( from http://openservo.com/ ) or the open-source Linistepper ( from http://www.romanblack.com/lini.htm )?
  • Is it possible to build a RepRap that, instead of using stepper motors, instead used slower, smaller, cheaper hobby R/C servo motors?
    • perhaps driven by the servo motor driver board plus magnetic encoder board combination -- MagServo or OpenEncoder )?
    • perhaps driven by the servo motor board plus a sub-$2 mechanical encoder?[2]
  • Is it possible to build a RepRap that, instead of using stepper motors, uses faster, bigger, more expensive DC motors?
  • Is it possible to build a RepRap that, instead of using stepper motors, uses faster, bigger, more expensive AC motors?
  • Is it possible to build a RepRap that, instead of using stepper motors, uses nitinol shape-memory wire?
  • Is it possible to build a RepRap that can print photovoltaic cells?
  • Is it possible to build a RepRap that, instead of using 8-bit Atmel AVR microcontrollers, instead uses 32-bit ARM microcontrollers -- perhaps one of the ones listed at Vaporware Electronics ?
  • Rather than limit the HW to a set number of Axis, Dynamically expandable Bus Driven Approach

Goals

There are a variety of ways of "improving" the RepRap electronics -- but, alas, several of these ways conflict with each other:

  • reduce the net cost of all the motors and electronics and connectors, when fabricated and assembled at commercial PCB fab and board assembly house in high volumes. This seems to imply putting everything on one board, eliminating the cost of connectors between boards; eliminating parts that are not absolutely essential to run a single RepRap with a single extruder; and using tiny narrow-pitch surface-mount components packed tightly together, to reduce the size and therefore cost of the PCB.
  • add one or more features that early RepRap electronics doesn't have
    • SD card reader and LCD screen so that it can run "stand-alone" disconnected from any PC host.
    • high-power stepper drivers to drive bigger, faster RepRaps
    • 7 stepper drivers so it can run 3 axis plus 4 extruder heads -- a Mendel Multiple Extruder -- or a Stewart platform plus 1 extruder head, etc.
    • lots of thermistors so it can occasionally pause and wait for motors and motor drivers to cool off if necessary, rather than covering them with enough heavy heat sinks to cover the worst case.
    • all the stuff necessary to interface with magnetic linear encoders or optical linear encoders to directly measure the position of the tool head. This lets the firmware immediately detect and correct "skipped steps" ... and also enables microstepping with optical feedback that may give higher positioning precision.
  • make it possible for people to fab the boards with a relatively crude homebrew process -- perhaps one of the Automated Circuitry Making techniques. This implies spacing parts relatively far apart to leave more room for the relatively wide isolation gaps and wide traces these techniques produce.
  • As far as possible, use only widely-available parts that are unlikely to go obsolete soon -- available from multiple manufacturers, etc.
  • Lots of flexibility to allow a variety of "functional units" to be substituted. Then the assembler can use whatever is cheapest at the time and location. Easy to switch to alternate parts if the original parts are unavailable. Easy to experiment by temporarily swapping in a new functional unit to test if it is really better than the old unit. Easy to upgrade just one functional unit if a better unit becomes available -- less buggy, more fault-tolerant, faster, more power-efficient, etc.
  • Each motor driver on a separate board, for the reasons listed at PMinMO: "Why Modular Designs?".
  • make it possible for people to assemble all the parts on the boards with relatively crude soldering tools -- this implies easy-to-solder parts, either through-hole parts or large wide-pitch surface-mount parts.

Perhaps the biggest philosophical conflict between RepRap PCB designers is between people who are aiming in two very different directions:

  • A completely stand-alone RepRap. A person turns on the RepRap, presses buttons on the RepRap to select "measuring cup" on its small LCD panel, and then the RepRap prints out a measuring cup. Since there is no PC hooked to it, all computation is done internally with a medium-cost processor, and all status shows up on the LCD panel and a few dozen blinking LEDs.
  • A "3D printer" as a dedicated computer peripheral. A person designs a new measuring cup on a full-size computer running his favorite operating system and his favorite 3D CAD software, hits "print", and then the RepRap prints out a measuring cup. Since it's hooked up to a PC with a (relatively) fast processor and (relatively) huge display screen, it offloads as much computation and status display as possible to the PC. The internal low-cost processor handles the remaining real-time tasks that cannot be done by the PC.

Testing

  • Does it work at all? Testing RepRap Electronics
  • How do I use the RepRap Stepper Tester?
  • How do I use the OpenCircuits Stepper Tester?
  • Does it shut off properly when it overheats or slams into an end-stop?
  • What is the cost compared to the standard RepRap electronics?
  • Does it print things faster than the standard RepRap electronics?
  • Does it print things more accurately than the standard RepRap electronics?

The process of releasing improved electronic designs in a way that makes it easy for other people to use and make further improvements is described at ElectronicsReleaseProcess.

Further Reading