MicroSD Adventures

My MicroSD adapters arrived in the post today, so I thought I would give one a try.

I moved the PIC18F4550 onto a separate breadboard as I seem to be running out of space for experimentation at the bottom of my current breadboard, plus I want to wire up the MicroSD adapter somewhere close to the pins it actually uses.

7 pins worth of header strip and 6 wires later (using the pinout mentioned in the last post) and I am ready to try it out.

Ribbon cable is only providing power, (plus it is easier to leave the pins for the USBasp firmware programmer connected than work out the correct pins again from scratch), I really must make a USB power cable – I have enough random USB cables, I can afford to cut one up for the job! You will also see the serial programmer still attached but with no USB cable connected.

Fire up Pronterface – promptly fails to start due to wxPython not being installed (previous tests have all been run from Pronsole which is purely command line).

Download and install wxPython and try again, still no joy – seems my Mac Mini is only 32 bit, so needs an additional environment variable setting first “VERSIONER_PYTHON_PREFER_32_BIT”needs setting to “yes” and then it starts without issue.

Connect to the Bluetooth connection, no message saying that the SD card is not present, so that looks good, upload an STL file, nice and fast, rendering takes a few seconds, and then try to save to the SD card – seems to be rather quick, so I check the SD card and there are no new files on it.

Try a few gcodes to access the card reader – M21 – SD Init failed – hmm…

Maybe the card is in the wrong format, so I try reformatting it, still no joy, double and triple check the wiring – all looks good.

I then notice that whilst inserting and removing the MicroSD card, the light on the adapter goes out – perhaps we have a bad connection (after all it is not soldered to the pins), just resting on them.

I lift up the board so that the opposite edge is making contact with the pins and try the M21 code again – no failure response this time, so I try M20 and am rewarded with a list of files from the MicroSD card – success.

Rather than continue to hold the adapter in place, I locate something to wedge it into the current position.

I then try uploading the gcode to the MicroSD card, boy is that slow, I can see why people generate the gcode and load it onto the SD cards from their computers – 39 seconds to generate the gcode file for Pirates of the Caribbean Coin, over 3 minutes to upload it to the MicroSD card via the “SD Upload” button! would be less than a second to upload via a USB adapter to the MicroSD card.

I use one of these:
Cost me £0.99 a couple of years ago, you can pick them up on eBay for about £0.44 now with free shipping from HK or China! Absolutely tiny (25x12x2mm), 10 times faster than trying to use full size SD adapters. and you don’t need a media card reader slot either.

eBay sellers in HK and China sell these sorts of things as loss leaders to inflate their feedback and sales history, costs them more in postage than they are selling the item for, so why not capitalise on that sales strategy? I will make up a suitable cable for the MicroSD adapter so it can connect to the Sanguinololu board in the same way as the SDSL, I added a bunch of female 10 pin IDC connectors to my last order from Rapid, they worked out at less than £0.10 each and use ribbon cable, of which I have plenty, although I could just as easily use individual pin connectors.

I am still not happy with my Prusa frame, despite having adjusted it again so that all of the bars are equal lengths and distances from each other, it still does not sit flat, nor are some of the bars parallel or making true squares. I am in agreement with Nophead on his blog, where he analyses the triangular structure, and all but states that it is not fit for purpose.

Still I will persevere with the structure, most of the items I have purchased can be used on another design at some point in the future, at the very least it needs to be capable of producing some replacement parts, or parts of whatever replacement I decide to build, as stated on the opening posts of this blog, There was never an intention for this initial build to be the end goal.

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