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AndrewBCN

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vreihen
They are calling it the "Red Rabbit" board:

http://www.3dxmy.com/?p=822

No sense of how they stand on open-source, but a huge concern that the firmware was apparently developed in-house and obviously has a lot of custom code to run the color touchscreen. On the plus side, the top-of-the-line board with a larger touchscreen and dual hotends is under $73 at today's exchange rate.....

If you don't have the source code or even if you do manage somehow to get your hands on the source code, but all the comments are in Chinese and/or it's not clean, easy to read the code, then it makes for a $73 paperweight. (td)

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TRoager
Found this :b maybe you can use that?
[github.com]

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dc42

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TRoager

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dc42
Yes I am looking at using one of the ESP8266 variants to provide the WiFi connection. The challenge is to get the wifi and I/O throughput high enough to give a good speed for uploading files to the SD card. This may require a major rewrite of the ESP8266 firmware.

Well i found this and looks like its quite active in periods :)

[github.com]

Like every other ESP8266 solution I have seen, that uses async serial comms between the ESP8266 and the host. That's OK for just monitoring and controlling the printer, but nothing like fast enough for file upload. The max achievable speed would be about 25kbytes/second, compared to 200kbytes/sec on a Duet using the Ethernet port (and work is in hand to increase that). So my first task will be to modify the ESP8266 firmware to use SPI with something like a 2Mbit transfer speed between the host and the ESP8266, unless someone has done that already.

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TRoager

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dc42
Yes I am looking at using one of the ESP8266 variants to provide the WiFi connection. The challenge is to get the wifi and I/O throughput high enough to give a good speed for uploading files to the SD card. This may require a major rewrite of the ESP8266 firmware.

Well i found this and looks like its quite active in periods :)

[github.com]

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dc42
Yes I am looking at using one of the ESP8266 variants to provide the WiFi connection. The challenge is to get the wifi and I/O throughput high enough to give a good speed for uploading files to the SD card. This may require a major rewrite of the ESP8266 firmware.

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dc42

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TRoager
Hows it going with the board dc42?? :)

I've given up on my original design, for two reasons:

1. The kit manufacturers I spoke to didn't want plug-in drivers, because on-board drivers are more reliable and bring the cost down. So the market for the board would have been limited.

2. Since I started the design, Replikeo has started second-sourcing the Duet. They are now selling it for $49.99, which is less than the price I would have sold my board at, AND it has Ethernet. The MKS SBASE Smoothieware-compatible has also appeared and is selling at $56.53. The AZSMZ Mini (a 32-bit board with plug-in drivers and no Ethernet) has come down to $50. So there are already at least three low-cost 32-bit boards available.

I'm now working on a design with built-in WiFi.

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TRoager
Hows it going with the board dc42?? :)

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dc42
As nobody has replied, I'll assume that virtually all users use the maximum microstepping available. So I'm not going to include microstepping jumpers on the board - they add substantially to assembly cost, and are one more thing for users to get wrong (as they often do with RAMPS). However, I'll make it possible to drill off the surface of a via (which is easier than cutting a trace) if anyone needs to change the microstepping of individual drivers.

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Don Recardo

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dc42


The parts cost is less than £15 including PCB. Assembling it in the UK would be uneconomic because of the large number of through-hole parts (i.e. the connectors), so it would have to be assembled in China. I'll get some quotations when the Chinese New Year is over. The initial selling price I had in mind was about £35, but if the production volume became high enough then sub-£30 + shipping + tax (where applicable) should be achievable.

.

Only just spotted this thread so probably a bit late to come to the party but
regarding assembly costs above , would it be feasible to supply boards with any SMDs already assembled but leave the user to fit the through hole components
Would the saving in assembly costs leave enough maybe to fit ethernet into the design?

Don

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dc42


The parts cost is less than £15 including PCB. Assembling it in the UK would be uneconomic because of the large number of through-hole parts (i.e. the connectors), so it would have to be assembled in China. I'll get some quotations when the Chinese New Year is over. The initial selling price I had in mind was about £35, but if the production volume became high enough then sub-£30 + shipping + tax (where applicable) should be achievable.

.

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AndrewBCN
@KDan & cxandy

I took some time to check the ESP8266 WiFi modules that are now available for around $3 from China and I have concluded for many reasons that they are not really fit for use to provide a WiFi connection for 3D printer controllers. They are really designed for IoT use and the bandwidth and latency they provide are geared for that kind of application. Besides that, I would describe them as "experimental devices", and would require considerable time and effort to interface (in software) to any of the existing RepRap firmwares.

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dc42
I still have this project going on the back burner. Schematic capture is nearly complete, and the most important parts of the PCB layout are done. Here is the specification:

Size: 100mm x 80mm x 22mm.
Processor: 32-bit ARM Cortex M3, 64MHz clock speed, 256K flash, 48K RAM.
Power input: 12 to 30V. On-board 5V regulator, with provision for attaching a heatsink to allow high-current devices on the 5V output e.g. TFT screen.
Stepper drivers: 5 sockets accepting either standard Stepstick-type drivers, or modified Stepstick drivers with digital control of stepper motor current, or a mixture of both. Dual Z motor connections.
On-board SDHC card socket.
I/O:
- Native USB port (not serial-over-USB)
- 16A heated bed output (I might be persuaded to make this 20A)
- Two 6A extruder heater outputs
- One 2A controllable fan output
- One permanent fan output (for hot end fan)
- Three endstop inputs
- 4-pin Z-probe connector, to suit just about any kind of Z probe
- Expansion connector with 11 I/O pins + power including UART, SPI, TWI. Uses include connecting PanelDue colour touch screen (uses 2 pins), or connecting 12864 mono GLCD + rotary encoder (uses 6 pins).
LEDs: one per heater, one for the controllable fan, one per endstop, one to indicate 5V power.
BOM cost (1000 off): approx. 75% of BOM cost of Arduino Mega + RAMPS.
Assembly cost: less than Arduino Mega + RAMPS.
Target selling price for first batch: GBP39/USD59 excluding VAT/sales tax.
Firmware: I will port RepRapFirmware to it. This is 32-bit firmware supporting Cartesian, CoreXY and Delta printers, with digital control of stepper motor current, flexible configuration using gcodes and gcode macro files (no need to rebuild and upload the firmware to change configuration), segmentation-free delta movement, fast delta calibration in a single iteration, and many other advanced features. If the board takes off, then I guess others will port 32-bit Marlin to it if there is enough demand.

The question I have is: is there enough interest in the board for me to justify having 100 manufactured; or would I end up with a lot of unsold stock?

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JustAnotherOne

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dc42
They haven't quoted a target price, but I expect it would be quite high, probably higher even than Smoothieboard.

If you look at the rewards, then you can get the BBP Board for $79 and the BBP 1S for $99

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cxandy
I have completed part of the test, repetier host 1.06 and smoothieboard connectivity, when printing at present no problems found now.

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dc42
They haven't quoted a target price, but I expect it would be quite high, probably higher even than Smoothieboard.

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veng1
@dc42 You might want to look at this Kickstarter to compare features and price:

[www.kickstarter.com]