StepStick - Allegro from snipermand configuring

As I mentioned in my last post I purchased a StepStick stepper driver from spinermand on eBay (link to item) and the trimpot kept turning.

I posted the a thread on the RepRap forums and promptly got the following reply.
On the 'normal' stepstick it would be the left pad and upper right. If your multimeter supports measuring resistance, you might want to use that to determine how far the trimpot is open.


Ironically enough the person how replied was (or at least seems) to be the same guy who runs RepRapWorld. Which I purposely avoided due to the questionable selection of parts in the RAMPS DIY kit.

Connections to measure highlighted

By attaching the multimeter in resistance mode to the highlighted points (see above image) on the new
StepStick then comparing it to be resistance one of my RepRapWorld StepStick I was able to match the settings.


For this reason I would avoid snipermand for StepSticks as it adds another step to the set-up and would be even more tricky if don't have a StepStick with a ended trimpot as you'd have to calculate the values.

Update

I just noticed that I haven't updated this blog in quite sometime.

Why the delay?

Stepper motor driver

Firstly the stepper driver I fried. It took about a week for a new one to arrive.
Instead of going with RepRapWorld (I choose against it due to the issues I had with the RAMPS kit) I brought it from eBay (link).

It worked out about £1 more, but I thought it would be nice to try a different supplier.
I ordered it on the 16/11/2011 and it arrived 24/11/2011, this alone set me back a full week.

When I came to install the stepper driver yesterday I noticed the trimpot (the little circular part at the bottom) kept turning.

I asked the supplier and got the following reply
There are no stops to these trimpots.
But you can adjust the current limit by measuring the voltage on the trimpot dial.
Adjust the voltage to 0.7 x max stepper current.

This means more testing and even more delay

Drill bits, drills and family business

When I planned for this project I took into account a selection of tools which my father owns. Unfortunately for me he was using them at my sisters new house which meant I couldn't just use them.
This set me back a few days.
Then when I finally got hold the a drill he didn't have a 3mm drill bit...

On top of this my sister is pregnant and she offered to let me go with her for the scans. I can build a RepRap any time, but my sister will only have her first pregnancy once.

Wire strippers and hot glue gun

These two items I brought myself and thought I knew exactly where they were. However it turns out a family member had borrowed them then another family member put them in a bag then into the back room*.

I spent a few hours yesterday cleaning out one of the large cupboards and still didn't find them. On the plus side I did find a selection of tools and strangely enough about £20 worth of women's beauty products.


*the back room is where all the random items go, similar to a loft only with fishing tackle and pet hedgehogs.

It lives (RAMPS)

After finally finishing the RAMPS assembly last night I thought I'd give it a test run.

In truth I was expecting it to go pop and not even turn. I did so many things wrong or in a roundabout way it is stupid.
To quote on of my favourite songs, Do as I say not as I do.

I found the easiest way to wire RAMPS up to a computer psu was to use the pin pin 12v yellow and black connector.
Snip the end, strip the wires then attach.
For anyone reading the RAMPS 1.4 wiki entry and wondering what the heck the COM wire is on  diagram explaining how to attach the power its ground.
COM = ground
It stands for common return path.
So using the 4 pin connector wires it goes;
*top near the 6 pin screw connectors*
Yellow
Black
Yellow
Black
*bottom near the reset switch*

A quick way to start an psu is to use a paperclip (I was told this my Corsairs psu technicians) from the power-on lead to any ground.

I powered on the RAMPS board, connected the usb then booted up the Arduino software (link to download page).
Windows 7 picks up the Arduino drivers, however with XP or similar you'll have to point Windows to the drivers folder in the Arduino software folder.
After setting the coms port to com 3 (generally you have two ports com 1 and com x, use com x) and board to 1280 I uploaded the test file (link).
To my utter surprise it worked, well the LED's all flashed.
So I powered down RAMPS and installed one of the stepper drivers (I'm using StepStick) and attached one of my stepper motors.

Before I installed the stepper driver I carefully turned the dial to 25% (all the way counter clockwise then back 25% of the way), however in a complete daze I installed the stepper the wrong way around.
Install the stepper drivers so the dial away from the mosfets.
Bam Windows no longer regonised the usb device and I instantly knew what I had done wrong.

Luckily it only blew the stepper driver and not the whole RAMPS board. Replacing the stepper driver with a new one and installing it correctly resulted in my stepper motor majestically turning left then right.

Of cause this means I'm one stepper driver down, but atleast my RAMPS works.

Avoid RepRapWorld for electronics - UPDATE DIY kits only

I posted earlier about a few of the pins being bent on the stepper drivers and the headers.

As the assembly went on I noticed more and more issues.

After the pins I discovered the red LED's where far smaller then the green LED (I suspect 0603). This made soldering them harder and much trickier.

As I neared the final steps I noticed RepRapWorld had supplied me with 6x 8pin headers (for the stepper drivers) as opposed to 2x 24pin header. This meant I had to file the middle headers and slightly force it in, both of which are risky to do.

On top of all this the Arduino Mega 1280 (a clone..) doesn't even come with a USB cable or feet. To make matters a little more confusing (to a newbie at least) its preloaded with the blink example.

Add all this to the fact it took them 13 working days to even dispatch the order, I'm not happy with them.

To top it all off when I mentioned RepRapWorld on the IRC channel Kliment instantly said RepRapWorld had caused people no end of hassle and he was getting annoyed with RepRapWorld.

Honestly if my RAMPS board ever works I'd be surpised.

OK I'll be honest some of the trouble is down to be and my tools*, but RepRapWorld have caused way more then there fair share of issues.

*I know the common phrase a poor workman blame his tools, but in my case my soldering iron tip was fubar and it seems like my soldering iron overheats.

Quick update - misc items

The crimps and connectors from Hobbytronics arrived yesterday.

The loupe (20x18mm) and 0805 10k resistors arrived today, pretty damn good considering I only ordered them yesterday.

The difference a loupe makes is immense. From barely being able to read the 0805 rating to being able to see the individual pixels on my phone.
This means I can be 100% sure my soldering is on spot on (well as best I can achieve).

I would highly recommend anyone who is even considering soldering ramps themselves to budget for one and I consider it an essential if you choice to assembly the ramps yourself.
Seriously the difference it makes counters the very small cost of one.

Fingers crossed my new soldering iron tips will arrive tomorrow and I can resume the soldering.

Connectors, crimps and wires

When I was initially budgeting for my build I didn't think twice about the connections I'd need for the stepper motors, endstop or anything else.
I just thought, I can save time and hassle by soldering them on.

Now looking at the time its taking to solder RAMPS (damn you tiny smd parts) I'm very reluctant to solder anything to the board. Its like a piece of art which is taking time to create and perfect
You don't go and whack a nail though the canvas on a piece of art now do you?

There is only one reasonable solution, crimped connectors.
However there are literally hundreds if not thousands of different connector types. All in different shapes and sizes.
After looking through the RepRap forums I found this thread. This gave two very important bits of information;
1. Dupont connectors are good for the job
2. The size is 2.54mm or 0.1"

This in mind I headed over to ebay to see if I could find any dupont connector. There were loads, however they were all based in the US or Asia. Both of which would take at least a week to arrive (without I paid a silly premium).
Back to google I went, after about 10 minutes of searching I found exactly what I needed at HobbyTronics.
A nice selection of 0.1" housings and both female and male crimps.

I figured I need 4 crimps per motor (excluding one of the Z motors), 2 for each end stop and 6 for the hot end (4 for the resistor and 2 for the thermistor).
So 28 ( (4*4)+(3*2)+6).
For the housings I need a few sets of 4 (for the motors), a few sets of 2 (for everything else) and some singles just in case.

Final basket

1x Female Crimp Pins for 0.1" Housings 50-Pack  - £2.25
1x Crimp Connector Housing: 0.1 inch pitch 1x4-Pin 10-Pack -£0.45
1x Crimp Connector Housing: 0.1 inch pitch 1x2-Pin 25-Pack -£0.59
1x Crimp Connector Housing: 0.1 inch pitch 1-Pin 25-Pack -£0.55
Sub-Total -£3.84
Delivery - £2
Total - £5.84

Bargain now I don't have to trash the connection on RAMPS.

PS. I ordered around 3pm and there where shipped at around 4pm.

Arrg, damn you 0805 resistors.

On Monday when I started soldering the smd parts I had managed to drop one of the resistors on the floor which luckily I found a few minutes later.
However last night I managed to lose 2 of them.
First it was a 4.7k resistor, which like the night before, shot out of the tweezers and off the desk. I did manage to find this later.
Second and most baffling lost resistor was a 10k. I opened the package on the plastic side, I resealed it then went to tin the connections. When I went to pick up the resistor there were only 4 in the packet where there should have been...
I looked everywhere, but couldn't seem to find it.

In the end I managed to find someone on eBay selling a set of 10 for £1.30 (with 1% accuracy compared to others on eBay with 5% or higher).

On top of this I noticed my soldering irons "hotspot" no longer seems to be the tip, but about 5mm down from the tip. I had tried sanding the tip then re-tinning, but it didn't do anything.
So I ended up ordering a set of replacement tips at £3 for 3.

While I was in a buying mood I purchased a loupe so I can check the finished soldering and properly read the resistor numbering (in case I ever need to change them).

Looks like I won't be done soldering until this weekend.

Electronics finally arrived!!!

During my daily refresh of RepRapWorld last Thursday (3/11/11) I noticed it was finally marked as dispatched and given a tracking number.

A lot of excitement and a few days later I received the package.
So last night when I arrived home I had a spool of PLA filament with a center of electronics.

Prep and Issues

First thing I noticed was one of the Stepstick pins was a little bent so I carefully corrected that.
Second was the scary size of the 0805 resistors, I was expecting small, but they are tiny. I envisioned them being slightly smaller then a grain of rice which was way off the mark. The best example I can give (pictures don't really show the size too well) is pick up a standard staple then cut one of the small sections in half thats roughly the size of the smd 0805 parts.

 

The last thing I noticed and what took the longest to rectify was lack of markings on the resistor packaging.
With the hardware Thingfarm had labelled each bag and the items which weren't labelled were so different anyone would notice the difference.
RepRapWorld on the other hand only separated the main components of the full kit; Arduino MEGA 1280, Stepsticks, Stepstick heatsinks and the diy RAMPS board/parts.

As the resistors weren't marked up I had to read the numbering from the top. Remember how small the resistor is (as described above), now imagine trying to read a set of 4 digits from them.
I couldn't find my magnifiying glass anywhere was after a lot of rumaging and fumbling I found a pair of 1.5x magnification reading glasses.
Luckily the only resistors which could be confused are the 3x 10 with 3x 1.8k and the 5x 4.7k with 5x 10k.
I used this resistor calculator to work out the ratings (last time I resistor values where back in school years ago).



The soldering

Tools used

I had these lying around
Soldering iron
Solder
I brought these for this project
Flux pen
Soldering braid
Tweezers

With my freshly marked up resistors and clean working desk I began the fiddly process of soldering the smd parts.
I used the official RAMPS 1.4 guide from the wiki (link).
I fluxed each contact on the pcb just before soldering and used this guide for my soldering methodology (the actual soldering starts around the 7 minutes mark).
C2 was a little hit and miss, but that was to be expected as it was my first go at real smd soldering.
LED1 (the green one) threw up another curb ball, Place these with the end having green dots away from the + mark on the PCB, fine, but my pcb didn't have any + marks on it. Luckily the images on the wiki show the + mark and it was fairly easy to work out which way was which.
For some reason the red LED's (LED2, LED3 and LED4) seem to have half the width of the green LED which made soldering them a little more tricky.
R13, R14, R15, R12 and R23 all went in fine. I'd recommend soldering R13 after R12 as R12 is situated between R13 and LED1 making it a little fiddly.

Now I bet your wondering why I stopped at R23 and didn't do R24 and R25 at the same time.
Well the answer is I had a slight accident. During the soldering of R12 to R15 I managed to touch a hot section of the soldering iron with one of my fingers. I wasn't a big deal and it barely tingled, however for some reason while grabbing R24 my hand trembled, causing the resistor to shoot off the desk.
I kept my calm and soldered R25 (as I didn't want to lose that as well), then spent about 20 minutes on my hands and knees looking for it.

I was just about to give up then noticed it had landed on the top of my pc and not the floor itself.

I soldered R24 in then called it a night.

My poor burnt finger

Time to order a loupe and clean my soldering iron (the tip isn't heating correctly).

I'll continue the soldering tonight.

Still no electronics

I've not posted any updates in a while as I've not been able to make any progress.

I currently have a full frame, set of stepper motors and assembled extruder (including hot end), however I'm missing the electronics.

From my experience building computers one of the first things you learn is check everything works outside of the case. Its too easy to screw everything in and cable tie the wires in place, only to find one part doesn't work. Leading to dis-assembling the whole thing just to find the issue.

For this reason I've not fixed in any of the stepper motors or hot end.

I ordered the RAMPS Full DIY kit along with some PLA on 16th October . On the 22nd I sent an email asking for a quick update and recieved the following message:

Dear Joseph,

There was a little problem with the RAMPS board. I will shipp it Monday by priority airmail and you will receive it within a few days!

I am sorry for the inconvenience!

Martijn

Shortly followed by:

Ok! Thanks.

Your board is now fully tested!

Kind regards,

Martijn

So I was expecting the order to be shipped on the Monday (24th) and arriving within 3 to 5 days.

I kept checking the order status on RepRapWorld and it never changed.
Now 15 days after I placed my order the status is still the same as it was only a few minutes after placing my order.

Below is a screen shot of the order.

Note the order is still processing and was placed on the 16th.