Back from holiday

Hi everyone,
I'm back.  I had a fantastic time away and it was good to see friends I haven't seen for a while.  Boston is a very pretty city and smaller than I was expecting.  Quincy market was great and I recommend anyone going to Boston to visit it.  Beacon hill on a crisp, but warm autumnal morning has a picturesque view of the common and is the location of a monument to the 54th Regiment Massachusetts Volunteer Infantry and Colonel Shaw.  Seeing the monument reminded me of the film Glory, depicting the endevours of the regiment.  There are lots and lots of things to do in Boston.

We did the usual touristy things: visiting the universities, museums and zoo; toured the sights in a DUXW (pronounced Duck) and went for a drive in the Charles river that run through Boston.  I was particularly impressed by the Science Museum.

Halloween was fanscinating - Americans really go all out to celebrate it, closing off roads and having kids street parties.  Students were of course enjoying wine and cheese while handing out candy. All very civilised and much nicer than my experience of Halloween in the UK.  :)

The Stanford online ai-class has been hard and was a mite tricky keep up with while I was away, fortunately our hosts were very understanding.  My results are good so far, but I'm surprised at the quality of delivery of the course, particarly the performance of the supporting IT infrastructure and it's to date lack of reliability.  Chatting to our hosts, it seems the quality of online course delivery in the US is generally very poor.  The expected culture is that you attend classes and be lectured at for umpteen hours.

Who else is doing the free ai-class?  I remember asking on the SumPod forums, but since they are down I have no other means of keeping in touch with other SumPoders(?) taking teh course.  A big shame I think.

I've got to sort out the inevitable backlog of work and stuff that builds up while away, but I'll be continuing my SumPod build as soon as humanly possible (including investigate Andy's [Andy who?] suggestion of using Marlin firmware) while writing up my PhD and family things.

I understand more SumPods are in the wild, more pics at 3D-printer-kit.com (I hope the upgrades for Richard's CNC machine have been successful, but I haven't heard from him) and the packages keep getting better with extras like a list of contents. 

Until then
Matt

Holiday Time!

I'm visiting friends in the states for the next couple of weeks.  So it's highly unlikely I'll be posting anything new on my SumPod build, unless I perfect the ability of being in two places in the same time; in which case I'll be rich enough to get Richard to assemble my SumPod for me.

Back on planet Earth, I'll still be checking my email and blog comments in case I can help with other builds.

Note to potential 'visitors of opportunity' in my absence.  The dogs are staying at home and they prefer their steaks raw. :)

SumPod Guinea Pig

Hello World! I am SumPod!

Continuing with the build and step by step testing of the SumPods electronics we have the LCD.  This is a generic 16x2 alphanumeric parallel display driven by an industry standard HD44780 compatible driver.  With a funky blue backlight and white text it certainly looks the business.

And it works!  It's nice when things work first time and as intended. :)

I'll document the connections after I've had some sleep.

Solder a pin header to the LCD with the pins pointing out of the back.

The connections on the LCD are:

1. VSS (Gnd)*
2. VDD +5V*
3. Contrast adjustment (VO)
4. Register Select (RS). RS=0: Command, RS=1: Data*
5. Read/Write (R/W). R/W=0: Write, R/W=1: Read*
6. Clock (Enable). Falling edge triggered*
7. Data Bit 0 (Not used in 4-bit operation)
8. Data Bit 1 (Not used in 4-bit operation)
9. Data Bit 2 (Not used in 4-bit operation)
10. Data Bit 3 (Not used in 4-bit operation)
11. Data Bit 4*
12. Data Bit 5*
13. Data Bit 6*
14. Data Bit 7*
15. Backlight Anode (+5v)
16. Backlight Cathode (Gnd)

*I haven't included core colour because you may not get the same 8 core cable, just assign a colour to each asterisked connections and make pigtails to matching signals

I would normally connect a pot between VDD and VSS and feed the wiper into VO, however the display supplied with the SumPod, performs nicely if VO is connected directly to VSS (and the SumPod kit doesn't include a pot), thus I save a component and some soldering.

Using the supplied crimps and housings build the cable to connect the LCD to the RAMPS board.  It should look something like this:

I use a small pair of ridged pliers to attach the crimps to the wires.  I find it easier if the crimps are still on the strip (and less likely to drop and loose them) and when finished then remove them.

The other end of the cable will look something like the image below.  I'm not sure about the distriution of crimp housing sizes, but for ease of assembly make sure you put VDD and VSS into their own two position housing.

I don't believe the custom SumPod firmware is available yet, so to test LCD operation I modified the Arduino LCD example sketch to work with the RAMPS board to display a message.

That's all folks!
SumPod Guinea Pig zzzzz

Updated SumPod RAMPS v1.3 Build

The SumPod RAMPS build varies very slightly from the standard RAMPS build, with the addition of the LCD connector.  In this post, I provide updated pictures of the RAMPS board, the ancillary stepper boards and the Arduino Mega.

Here are the pics, first up we have pictures of the two variants of the RAMPS board, one of which you will receive with your SumPod.  They are electrically identical:

Gold pads

Immersion silver pads

I prefer the second board type, with the silver pads, because it has a silver immersion finish; the overlay shows the resistor values and there is a fraction of a millimetre difference in component clearance (or my imagination) of the socket and pin headers at the top right of the board making assembly easier.  Other than that they are identical.


The additional 4 pin headers (each labelled 2B 2A 1A 1B) are required for stepper motors X, Y, Z, E0 and E0.  With the LCD pin header on the far right my RAMPS board looks like this:

Mounted in the Arduino Mega 1280 dev board:

With the full complement of five A3983 stepper driver boards for the dual feeder based system:

The overall board stack looks like this:

When mounting the stepper drivers ensure they are orientated correctly.  To help this legend on the underside of the driver PCBs indicate the pin function matching the legend on the RAMPS board.

Uprated PSU and Improved Stepper Performance

Currently the SumPod uses a 12VDC supply.  I am intending to use a higher voltage supply (24VDC) because superior stepper performance is possible, and besides the driver boards will run at voltages of up to 35VDC.  

Since the SumPod comes with high torque (44Ncm) hybrid steppers using the chopper current limiting stepper drivers, greater speed is possible with a higher voltage.  This is because of the natural low pass filtering that occurs with an inductor (stepper coil).  As frequency of pulses increases the amount the stepper coil energises (directly affecting torque) reduces.  Increasing the voltage proportionally improves energisation rates and hence top speed.

.

I realise the Mega 1280 board supports a maximum input voltage of 12V and I intend to use a DC-DC step down converter to provide an acceptable supply.

LCD

I haven't yet connected the LCD, but here are some pics and technical details:

Datasheet for LCD

Until next time

SumPod Guniea Pig

SumPods Have Landed and Dancing Motors

I spoke with Richard earlier this evening and he confirmed other SumPods had been released into the wild.  This can only be a good thing, with eager owners now (feverishly? God I've got to get out more!) building their new 3D printers and Richard getting the feedback he desires.

Me, I'm still waiting for a print bed part to arrive. I noticed at the beginning of the week when I started assembling the SumPod MDF parts that something was missing.  I'll proceed with the mechanical build when the missing part arrives - it should have turned up two days ago checking with Richard.  Richard isn't the only one suffering from delays - hurry up Royal Mail!  Rather than sit on my hands or write  more of my thesis (God I hate thesis writing and this blog provides some light relief), I soldered up a few more bits of the SumPod and coaxed a few of the stepper motors into life.  The following short video shows my progress.

It may not seem much, but to me it's significant, the equivalent of getting a LED to flash at the right frequency on a newly designed board.  It proves the software toolchain and hardware are working.  For the SumPod it means I've correctly soldered the RAMPS board; downloaded the complete Sprinter firmware from GitHub, modified it to work with the RAMPS hardware and uploaded it to the Arduino Mega 1280 board; soldered up the steppers correctly and got ReplicatorG working.  Phew!


The following steps describe how you could replicate this experiment to check your software and hardware setup:

Hardware
Stepper motors connections are as follows (taken from here)

Zapp Automation / SY42STH47-1684B

Stepper motor datasheet

Pololu Pin	Colour
2B	Black
2A	Green
1A	Red
1B	Blue

I used some of the leftover socket headers from the RAMPS build, soldered to the stepper motor leads to connect to the RAMPS board.  I'll post later the updates I've made to the RAMPS board.

Software

Plug the Arduino board to a computer using the supplied USB cable. Now for the software.

1. Download the Arduino software
2. Download the Sprinter firmware I've selected this because it has built in support for printing from an SD card.
3. Extract the Sprinter firmware into the hardware folder of the Arduino software directory.
4. Open the Sprinter.pde file using the Arduino IDE and edit configuration.h for the correct board #define MOTHERBOARD 33 
5. Now edit the pins.h firmware file, changing the X_MIN_PIN, Y_MIN_PIN, Z_MIN_PIN to -1 (to disable them otherwise your steppers will only go in one direction during your test) in the MOTHERBOARD == 33 section.
6. Click verify in the Arduino IDE to recompile the firmware.  You shouldn't get any errors and the updated firmware can be uploaded ready for the next stage.
7. Download ReplicatorG
8. Run the ReplicatorG and connect to the board.  Select the correct serial port and Klimetkip (115200 baud) Drive under the main Machine menu.
9. Now click the Control Panel button after connecting and you should be able to replicate the little stepper motor dance from the video.

Enjoy.
SumPod Guinea Pig signing off

Investigating 3mm Filament for the SumPod

I'm thinking of sourcing the parts (initially just the tubing) to use 3mm filament with the SumPod.  The trouble was, I didn't know the exact dimensions of 3mm filament.  Checking the wikis and reading through various blogs, I was none the wiser of the elusive dimension (or my search skills have abandoned me) and hence the required tube size.  Was the filament less than 3mm in diameter?  If so I could use a metric 3mm PTFE tube or was it actually 3mm, and require an imperial 3/16" (3.2mm) inside diameter tube?

Not getting anywhere fast I decided to buy some.  Specifically some PLA filament from Fabadashary.co.uk (no affiliation).

Once before I had dealings with this company, for their 1.75mm rainbow filament kit.  I was happy with the site and the speed of delivery (UK based, so not really surprising).  The real plus and my reason for going back for this application is they offer short lengths of filament (minimum 5m). Utterly perfect for my needs.  For anyone that doesn't know they hold the widest range of coloured filament I have known a comapny to stock.  They were nice enough to include some sample filament along with my original order for some 'mellow yellow'.

 

Measuring the filament in several places along its length to check consistency,I can happily report a diameter of 2.8mm, with a variation of no more than a 0.04mm.

Now, I am making the massive assumption that 2.80mm is the actual size of nominal 3mm filament.  If I am mistaken and anyone knows any better please, please, please comment below, before I waste money on the incorrect inside diameter tubing.

Now I know the filament diameter, I will source some appropriate PTFE tubing.  When I get a working setup I'll post my findings.  In the meanwhile, if as I suspect others are looking at using 3mm (2.80mm?) filament with their SumPod, due to the lower cost, I am happy to supply lengths of tubing.

SumPod Guinea Pig signing off

SumPod Unit Visit

I have visited the unit where Richard builds the SumPod; it's real and bigger than it looks in the pictures.  I was asked nicely and agreed not to take photos inside the unit, until he is happy with it's condition.  Nevertheless, Richard is happy to accept visitors, as per his email:

Hello,

Kits are being finished off but unfortunately due to cutting parts off-site and at night I am not able to finish these until I return back to base. I still think even given this I should have sent all first campaign within the next few days and that some of the second should be ready and hopefully sent at the end of the week. There is a long list of jobs but I am getting through them.
These problems would not exist when the cnc machine I bought is fixed as I can do all hand finishing and other jobs whilst parts are cutting,
To allay any fears and for those willing to travel, the postcode of my unit is ########, ######. Its not much to look at as this was phase two but you can see the setup is real and I can show you the problems with the cnc machine. My phone number is ############ but when at the unit I am only reachable by mobile, ########### which is quite flaky. I am willing to call anyone in person, please just email me a best time. Please allow for time difference although I am up most hours.
I am truly sorry for the delays.
Please email (or call) me if you would like to visit and I can call and arrange a time.
Lastly the site will be fully functional soon with extra content.
Thanks
Richard

This email was sent on the 10th October.  I have redacted his personal details for publication on the wider web. I think Richard didn't appreciate the quantity of work he was taking on and suffered unforeseeable delays due to faulty equipment (specifically the brand new CNC router).

That's all for now folks

SumPod Guinea Pig