Today I thought it would be a good idea to make A sd-card reader as an extension for my Ultimaker, I designed it for the newer electronics which can use the SPI pins because there is a break out to an expansion header. Because I printed a prusa mendel on my Ultimaker a few weeks ago and I’m aiming to use Ultimaker electronics for it the new printer.
The schematic and board layouts are down here, here’s the download.
About a week ago I found out a few things like:
The 15 euro 600w oven I bought some time ago is pretty good for a reflow oven, I now use it for baking PCB’s (in stead of bread:) It comes in about 3:48 seconds to a temperature of about 165 degrees Celsius, which is perfect since I’m using this dealextreme solder paste. The paste melts at about 155 degrees Celsius and gives me a real nice result with shiny solderings ( http://www.dealextreme.com/p/lodestar-soldering-paste-50g-4711)
I do not even have to use a temperature regulator because of the relative low temperature, perfect!
Another thing I found out was that is is pretty difficult on deposit the solder paste on small pads. About a few days later I found this site: http://www.millpcbs.com/ The site gives a lot of usefull information about milling PCB’s, but there is also an article about milling a solder stencil, which was perfect for me! (http://www.millpcbs.com/index.php?option=com_content&view=article&id=28&Itemid=49)
So here’s the result, first try:
The plastic I used is a bit to thick but for this small job it worked fine. Below are a few pictures, I used some tape to place the stencil on the PCB, then I filled the holes in the stencil with paste using a little plastic card.
Then I baked the PCB in my mini oven and the result was pretty good:
I even soldered the Transflash micro sd socket in the oven and they didn’t melt 🙂 I bought these ones very cheap ($4,99) on ebay (search for: 10PCS TransFlash TF Micro SD Card Socket Adapter).
So there’s the result:
Now I can use this add-on for controlling the Ultimaker without a computer, but first there has to be code written for reading a sd card and use the data on it. The idea is that the Arduino mega reads the gcode file on the sd-card in stead of receiving the gcode from the computer (serial).
In the mean while I can use it for discovering the SPI function from my bus pirate and learn how to work with sd-cards without writing code!