The DIY Opencockpit thread....

[simunut]

Hello folks,

I just finished several opencockpit cards and may have useful info for anyone wanting to go the same route.

I plan on editing this first post with all the info I have, making it the first thing users see. I will include a few suppliers that I have found helpful(in the US). I will also include tool info along with a few tips I feel worth passing on. Finally, I will add a BOM for the following cards:

USB Expansion
Master card
DISPLAYII
USB Relays
7-segment LED
USBLCD
Encoders Card (still building)
Others as I build them.


Suppliers:

If you are in the US, you can get just about all your misc parts from this place http://www.phoenixent.com/
Explore their site! Phoenixent has just about every connector/pin/socket/hardware/tools we need for building OC cards.

Digikey a no brainer for parts
Newark has won me over.. saved tons vs going Digikey
octoparts.com is a neat search engine for parts.

Tips:

Check your items when they come in ASAP. Most of our orders will be broken down from larger stocks. I have overlooked missing caps from an OC encoder kit as well as not getting all my items from digikey. We are all human and accidents happen.

Because I was building a bunch of cards at once, I basically kitted each card. I got ziplock bags, printed out pcb diagram/bom and made little kits.

Do not try to build more than two master cards in one day You will start to see things after the 90th diode.

Make sure to get the right size solder for the job. I recommend starting at .031 in dia.

Make sure the solder tip is the right size for the job. Some of joints are in tight spots. (I use a hakko fx-888 with its default tip)

Start with the lowest height components first.

Plan ahead when down to the larger components.

Be mindful to the orientation of diodes,IC's, leds, #1 pin of the IDC connectors and the 5vdc power pins.

Prior to powering up the cards, recheck all solder joints under a magnifier.

Have datasheets handy to know your way around the ic chips if you get into trouble

more to come.....


FWIW.. All but two of my cards worked without any problems. My laptop did not see the first usb/mastercard combo. After sweating it out, rechecking joints, cursing while metering voltages at the ICs, I tried a different usb port and it worked.

My second usb expansion card suffered from me not paying attention to the orientation of an IC.

OC BOM v1.01.txt

I plan on posting the BOM as text vs an attachment. Just need to figure out why the formatting goes crazy when importing from word.

[UKV1342]

hi,
can i offer some tips - please incorporate if you agree - but please remove this post when you have read
1 always use header plugs for all ic's - its false economy to solder into board - the board is worth more than the ic and heat is virtually the only thing that will kill it (desoldering chips)
2 when out buying your soldering iron buy a wrist band with extension lead to earth board and more importantly the chips when they are taken off of the expanded polystyrene transport medium. The chips are generally CMOS devices and hate static electricity
3 make an earthing kit - simple 12" square tile that is wrapped in cooking foil - attach wrist strap to the foil when moving IC's
4 use tweezers to move ic's from transport medium to foil prior to inserting in the board. put the board on the foil and push down to make good contact with the soldered pin connections under the board. now using tweezers - lift ic and check leg distances against headers. if necessary to bend inwards (usual because they are make to go in 'cutting' the metal in the headers to make a good contact) put the ic sideways on the foil and push down slightly. (you still got the wrist strap on yes!) insert ic in header and push down smoothly and check no legs bent inwards underneath chip before pressing home all the way. a firm pressure is needed to make sure they seat well, IC's that are not properly seated have a habit of popping up when power (heating form circuits inside) is applied but usually not for weeks after and then the head scratching starts !!!
Mike
Have also built OC kits sucessfully

[Dwayne Dibbley]

in the OC BOM V1.01.txt you mention for the USB Expansion that for C1 the value changed add 0.1mF cap. where/why has this changed as i have mailed OC support and they say it should be a 220 nf still??

Thanks

[simunut]

Hello Dwayne,

Consider yourself lucky in contacting OC and getting a response![being you're a diy type] I found out about the substitution via the opencockpits site:

http://www.opencockpits.com/modules....ic=339&forum=7

http://www.opencockpits.com/modules....ic=800&forum=7

http://www.opencockpits.com/modules....c=1061&forum=7

http://www.opencockpits.com/modules....c=2195&forum=1

http://www.opencockpits.com/modules....c=2519&forum=1

http://www.opencockpits.com/html/ioc..._english.htm#2 – El montaje de la placa USB

Assuming that the response you received was recent, I am confused why they would tell you that. Know that all three of my usb expansion cards are running fine with the 0.1mf cap.


Hope this helps.

at work now... will clean this up later.. just wanted to respond quickly

Round 2 coming up for building cards.....

servo
stepper
plan on programming my own microcontrollers too!

[Marsh]

Curious to see how this turns out. So far I've made my own servo and stepper cards. Haven't tested the stepper cards yet (need to find a source for stepper motors). I layed out my boards working off the GERBER files and schematics. Then redrew the traces in AutoCAD. I'm currently working on a combo USB expansion/mastercard. Might end up going with a stacked board. I did a 2-sided board for my stepper cards and I prefer not to do that again. I'm chopped some of the redundant components off as I only need to run one mastercard...just need to be able to run that mastercard from a USB. I have more confidence in the GERBER files than I do the schematics so I'm ending up layering the traces in Photoshop and painstakingly following all traces to verify where they go.

[UKV1342]

a simple source for testing is to use old printer head motors or cd/ dvd motors - How many of us have old computers / printers hanging around collecting dust

[Marsh]

a simple source for testing is to use old printer head motors or cd/ dvd motors - How many of us have old computers / printers hanging around collecting dust

I raided the scrap electronics bin at work and got a bunch of stepper motors. Thing is they are all different sizes, types, operating voltages and some are integrated into a pcb. Would be nice to have all the same.

I gave up on my USB expansion/mastercard combo project. Even on a 6x9 inch board I had trouble fitting in all the traces. So I got a demo of Diptrace (autorouting software). That couldn't do it either. So then I thought about stacking boards, but then I could easily have $40USD just in the boards. So that was pushing the limits of a toner transfer DIY PCB project. So I placed my order to the guys in Spain for an expansion card and master card kit. So now I'm working on an IO breakout/relay card.

[simunut]

I raided the scrap electronics bin at work and got a bunch of stepper motors. Thing is they are all different sizes, types, operating voltages and some are integrated into a pcb. Would be nice to have all the same.

I gave up on my USB expansion/mastercard combo project. Even on a 6x9 inch board I had trouble fitting in all the traces. So I got a demo of Diptrace (autorouting software). That couldn't do it either. So then I thought about stacking boards, but then I could easily have $40USD just in the boards. So that was pushing the limits of a toner transfer DIY PCB project. So I placed my order to the guys in Spain for an expansion card and master card kit. So now I'm working on an IO breakout/relay card.

Bummer, I was curious to see how your combo boards turned out. At one stage, I wanted to build the boards up from the gerber files... but that was wayyyyyy too much for me. Please keep us posted on your io breakout/ relay card. Always good to see the diy works of others.

Not to scratch your IO plans... but you should check out this item on ebay. Search for Omron xw2b-40g4. About a year ago when they had a bazillion of these for sale .. I got them as low as 8 bucks a unit. Lots being sold under 'make an offer' are where you can really clean up house. I think they are the perfect IO breakout solution.


Anyhow... keep us updated...

simunut

[Marsh]

That Diptrace autorouting program is pretty neat. Saves a lot of time. I already laid out the breakout out I/O cards. Currently laying out a display card. Do you need to add resistors to those 7-segment displays? I can't find the displays manual on the Opencockpits website, but they show diagrams on how to connect the displays - no resistors. The 7-segment displays I found all seem to have about a 2V forward voltage and as far as I can guess, the cards are outputing 5V. Makes me think I'd need a 100 ohm resistor in series to each LED segment. Yes or No?

[fordgt40]

No. You do not need resistors for the 7 seg displays when used with the OC display card/circuit as they are multiplexed ie turned on/off rapidly.

David