Build Thread- SLAmStepper & BOB Construction thread

[racedirector]

Hi All

Thought I might document the build of my SLAmstepper boards and 4axis BOB I bought from James Newton.

I'll start with the 4 axis BOB, a nice simple one to get me going. First up is a pic of what a kit contains when you buy a 3 axis kit with stepper drivers.



What is displayed here is:

The board itself, capable to handling 4 stepper drivers, relays, limit switch connections and parallel port for connection to your PC.

The 5V power kit consisting of 3 capacitors, 3 way connector, LED, resistor, voltage regulator and diode (hidden).

3 limit switch connectors plus resistor pack

4 way cable for connection of up to 4 stepper drivers

DB25 parallel port connector (attached to the side of the PCB - not soldered yet)

There is also a 6ft parallel cable (not shown) that comes with the DB25 connector.

Tomorrow I will start putting all the bits on the PCB, I will take pics as I go so everyone can see how this thing goes together.

Question for James if he pokes his head in here.....

The instructions talk about the relay driver but as that option is not yet available I couldn't get one. What components do I need to install that as well?

Anyhoo, more tomorrow.

Cheers
Bruce

[racedirector]

So here I am again, continuing on with my build. I have finished the BOB to the point where I need to wait for answers but I will so each component as I went along.

Oh and I use a Goot 45W pencil iron and .71mm rosin cored solder. I find the 45W iron gives good heat for short bursts rather than having to hold the iron on the part for too long while waiting for things to heat up.

First up, the DB25 Parallel connector is soldered on. This will only line up with the pads one way. Mine arrived pushed on to the board but it is simple enough to get it on if you start at one end and slowly fit it to the pads. Heres my end result:




It is recommended that you alternate ends when soldering to allow one end to cool before soldering the tab next door. I actually went from one end to the opposite end on the other side of the board just to be safe.


The next suggested item is the axis cable header but that gets in the way of installing the relay driver so I waited until I find out about that.

So I moved on to the 5V power section; These are all the 5V power related parts:



You start by installing the diode, D6. Just match the striped end to the board and bend the legs to match the hole spacing. This next shot show the diode fitted plus the entire section of the board that the 5V parts utilise:



Up next is U2, the power regulator. This is fitted to the board so the mounting tab is towards the outside of the board:



Capacitors are next starting with C4, thats the big guy in the parts pic. It is suggested the this be fitted to the opposite side of the board and be made to lie down on the board itself, attached with double sided tape or a blob of silicon. Thats what I did making sure the + leg was in the right hole, the "square" one:

From the bottom of the board:



And how it looks from the top:



C5 is next, again making sure the + leg is in the right place:



I fitted R5 the resistor next, it needs to be standing up as the holes are close together and there are other items around it. Simply bend on leg over 180' and fit the two ends into the respective holes:



And then C6, the little yellow ceramic cap goes in next to R5. Now, the instructions on the piclist site make no mention of this little cap. From what I could gleen from the pictures there, it goes in with the lettering facing away from the edge. Looking it up on the web showed no info of + & - legs so I went with the lettering distinction:



I should have fitted the LED next but I want to put that in the panel on my future enclosure so at this stage I have left it off. I am considering fitting a 2 pin header here (if it will fit) to allow me to disconnect the LED from the board if I eve need to take the BOB out for any reason. Having the LED in my panel with show me that the 5V side is working as expected.


So the final piece of the 5V supply regulator is the connectors for the actual power itself:



I then moved down to the limit switch side of the board and fitted the resistor network needed for the switches to function correctly. No pic of that yet, will get one when I fit the limit switch connectors.

QUESTION
The limit switch connectors. As far as I can see from the board traces, there are two possible way to fit these, one is sideways as in the images on the piclist page (on the right of the screen printing) and "forward" with the connections pointing out to the back of the board. This is done by using the hole in the centre of the switch markings (towards the left of the screen printing). Which one is right or preferred?

Tomorrow I will document either fitting more to the BOB or starting a SLAM board.

Cheers

[James Newton]

Nice! Anyone wondering how Bruce is figuring out where the components go and which way 'round and so on should know that there is a printed booklet of instructions included which is printed from this web page: techref.massmind.org/techref/io/stepper/linistep/4axis5build.htm which includes step by step directions for assembling each option on the board.

That's important, because that PCB is complex as all heck, and there are a LOT of options available for it, only about half of them actually relate to it's use as break out board for the stepper motor drivers. More details on other possible uses at:
techref.massmind.org/techref/microchip/bob.htm

As to the relay driver, the schematic is at:
techref.massmind.org/images/member/RB-ezy-Q33/4axis/4axis4sch.png, and the relay part is just below center, starting with R2, C8, Q1, D8... D7 and R3 are optional. All the part values are listed, and the sizes should be obvious from the board. I'm working on a kit of parts for sale, and I'll let you know when that is ready.

[racedirector]

Thank you James I forgot to mention the instruction booklet you supply, will make up for that when I build a driver

Thanks for the pointer to the scary schematic. As as junior geek I am quite proud of myself for a) finding the section I needed to look at and b) actually working out the parts list There are two reasons I want to relay driver - 1 to turn on my vacuum/dust extractor at some point in my machines life and 2 so I can install that pesky iN4001 diode before installing the cable header due to the melting problem highlighted in the docs. I should be able to get the parts from the local Jaycar store today but will definitely buy a kit from you when they are ready to support your efforts. I will be buying another SLAM driver anyway for my planned slaved X axis on my next machine.

I'll continue this thread later this avo after I get back from buying the parts I need.


Oh, and did you see my question regarding the limit switch connectors? If you could clarify that I can pretty much finish the BOB off today...

Cheers
Bruce

[racedirector]

James, if you pop your head in here again before I need to go out... I am having trouble locating the 10n cap (C8) for the relay driver, basically because I am not really sure what I am looking for. I have deduced it is a little ceramic bugger but the 10N has me stumped, any chance of a hand up with that one?

One other question on the relay driver, how many relays can it actually drive?

Cheers
Bruce

[James Newton]

So the right way to install the limit switch connectors is which ever way you like the best. The prior version of the board only had holes for the 90' orientation, the hole in the middle you found is a new thing and I haven't replaced the picture yet. ,o)

In order to use less space on schematics and PCBs, I use a shorthand where the prefix letter (M for Mega, K for Kilo, m for milli, u for micro, n for nano) is put in place of the decimal point. So a 4.7K Ohm resistor is 4K7; the Ohm symbol is just dropped... it's a resistor so what else would that be? That takes 5 symbols down to 3. A 47K would be... well... 47K. 1M, 2M2, and so on. 470 is just a 470 Ohm. It can be a bit more confusing for a 680K Ohm as that would be M68... see why? 680K is also 0.68M. But if I have room I write 680K just to be a bit less confusing.

So cap with 10n is a 10 nano farad cap. And honestly, anything in that general range will do just fine. It's just there to keep the signal from ringing.

[racedirector]

Excellent, thank you. Just quickly looked up conversion charts etc and am getting my head around all this sizing - 10nf = .01uf = 10000pf - the mind boggles! I am learning so much here, it's really cool!

Good news on the switch connectors, I'll move the resistor network to underneath and put the connectors facing out for easier connection.

Cheers
Bruce

[racedirector]

Well, I will definitely be wrapping up the BOB build today, I just returned from Jaycar with the required parts. I also picked up everything bar the hall effect switches that I need to implement Roman's home/limit switches, almost bought half the shop in different resistors to try out! Anyway, I digress. Off to fit my new .3mm tip to my iron and get started....

Cheers

[racedirector]

So to continue and finish the BOB....

I got a little carried away with the relay driver parts and forgot to do a blow by blow account. Sorry 'bout that. But here's a pic of the finished section:



The little white 2 pin header you see is not a standard item, a LED would go in this position. However, I squeezed this header in here so I could remote mount the LED in my future control panel, it will just plug in to this header.

I also got another 2 pin header and installed it over in the 5V power section. Again, the standard is an LED directly in the board but, again, I am remote mounting my LED's:



Having done those 2 things I moved back to the driver cable header. As suggested by the instructions I put it under the board so the top is not so crowded. Here a shot of where it would have gone on the top:



and one of where it is now, on the bottom of the board:



Now the next thing is going to have James cringing.... try as I might I could not get the resistor network off the top of the board like I wanted to. It was going to go underneath. As I still wanted my switch connectors to face the front pushed the network over so I could fit SW4 connector in the way I wanted, plus I trimmed the little tab off the connector. I then soldered the remaining switch connectors in facing the "front" for easy connection:



So now my BOB is done, at least for the time being anyway Here is an overall of the board minus the cable:



I will now move on to documenting the construction of a SLAmstepper driver as well.

Later....

Cheers
Bruce

[racedirector]

Another question for James:

Now I am done can I connect 12V to this to test out connections, LED's etc? Safe to do without breaking anything?

[RomanLini]

Hi Racedirector, I'm not James (obviously) but when connecting power to a PCB build for the first time it's good to use a PSU limited to only 50mA or 100mA.

Or if you don't have a current limited supply like that, you can put a 100 ohm resistor between the 12v supply and the PCB. If there is no fault the resistor will do very little, but if there is a short circuit, or reversed component etc the resistor will limit the current and generally save the day.

Once it all tests ok the resistor can be removed.

[racedirector]

Cool, thanks Roman. I'll wait until my power supply is fully built and then I'll try. I have 2 or 3 projects ging on in tandem at the moment, I should really finish one before I get onto the others but it is sooooo tempting to play with what I have