Author Archives: sandy

sandy

About sandy

Designer and builder of Polargraph machines, software etc.

Who will rid me of this troublesome SD card reader

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Happy New Years Polargraphers!

So I got a recent report from a soul who was impeded by an SD card not reading in his new PolargraphSD machine… And these are cards that I’d supplied along with the kit mind, so you’d expect them to work right?

Well, I did too. I could replicate his issue perfectly – New 4GB Kingston SDHC card (from this giant batch I’d patted myself on the back for getting such a good price on, and so many!…), that shows up during the Polargraph boot sequence as having no usable partition. Oh. Yet try the same card in an older machine kit and it shows up fine. Huh. What’s that, ah the touchscreen (which incorporates the SD reader, and I buy as a discrete unit) is now v1.3 rather than v1.2. Hm. I hadn’t noticed that.

Yet the 4GB cards work fine in everything else I put them in, they read and write and format fine on a computer. So that’s a problem. Luckily for me (and the next couple of orders) I _do_ have some spare 2Gb cards that work fine, so it’ll not slow delivery, and of course I’ll be sending a replacement out to anybody who has got one of these 4Gb cards late in December. That was obviously a goof.

Furthermore, the 4GB card works ok when powered over USB, but not if a higher-voltage supply is connected as well (or instead of). It’s a power supply or signal level issue.

In software, this kind of regression testing is second nature, in hardware, I suppose it should be an even higher priority because the stakes are even higher. In software, unit tests can be rattled out in an afternoon, and can be messed up a hundred times with only a time penalty. In hardware mistakes are expensive, and making up test jigs is another venue for mistakes to occur in.

None of that is an excuse, it’s just a convenient explanation that I’d give to the pointy-haired boss (which in this case .. is myself …  that’s frightening). It sounds comically like the same excuses I’d give to bosses in bygone times about why it wasn’t worth doing unit testing in software, ha. Embarrassing.

The devil here, if we must have one, is in the detail lost during the commoditisation, homogenisation of resources and products – On paper, v1.2 and v1.3 of the reader are identical, and the SD cards also are identical. No reason to think they wouldn’t work together.

So, the takeaway is that if you ordered a PolargraphSD and got an SD card that isn’t working in it, and I haven’t already been in touch with you, drop me a line, or buy a replacement 2GB SD card and bill me!

The reason I’m dwelling on these issues of delays and problems so much, is not [just] because I’m a masochist, it’s because I think it might be useful for other folks who are venturing down this same kind of path as I am. Not helpful directly, but I admit I always found the war stories inspiring.

Happy Holidays

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So the building that my workshop is in closes down over the holidays, from now until the 2nd of January, and like Bagpuss, when the studio goes to sleep, the Polargraph Company goes to sleep too. Of course I NEVER sleep, and will hopefully get a bit of time to finish the polargraph processing library over Christmas and New Year. That and Battlefield 4.

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There’s a couple of new professional developments that might bear some fruit next year too, including a project with the Science Festival to make a big, show-and-tellable version. I’m hoping that will be a springboard to get auto-homing working properly, and do a bit more work on large scale machines.

Thanks to all the folks who have supported me this year, I hope you think it’s been worth it.

See you all in 2014!

Sorry I’m slow again, but on the other hand, you are fast (like Dreamcast), and you make my day

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I got a good portion of the backlog moved when I got the batch of PCBs in, and PCB production is going fine.  I’m waiting on LCDs though. More about that in a minute.

I noticed we silently broke through the 200th Polargraph mark last month: Since September 2011 you’ve helped me move parts for over 200 drawing machines.  I think that’s remarkable, and for that, I salute you, drawing warriors!

In particular I would like to thank all the folks who have contributed to the forum, or written elsewhere and brought more people to the community. You know who you are.  

This is probably the first time I’ve been involved with something that wasn’t already happening anyway, and it’s very gratifying indeed. (Also mildly terrifying.)

So, now, back to our scheduled apology:

I know it’s pathetic to be waiting on parts (it’s not like it’s a surprise requirement), but I was surprised to find that the last handful of LCDs I had in stock were all cracked.  Still work, but not really usable for paying customers, what.

I’ve got a mega big batch of LCDs arriving soon, and they have been arriving soon, since I ordered them a fortnight ago.  I’m just going to have a whinge, so I apologise in advance – everybody else I know has already heard this whinge more than once, so it comes to you, kind, gentle, compassionate reader.  Long lead times is fine, and short lead times is great. Reliable lead times is best. The previous batch of LCDs I ordered astonished me by arriving 5 days later, from the other side of the world. Amazing! So, after ordering this next batch two weeks ago, I was expecting it to be here by now, but in fact I only got a tracking message about it yesterday, saying it was in Hong Kong.  Oh: less amazing.  The good news is that it means it’ll be here some time next week, the actual delivery is air freight, so super fast.

I’m only really exposing this whinge to indicate that I share your pain and to wave a pathetic little white flag. It’s dead frustrating to have ordered something, and then not to have it a month later, when you were quoted a month as lead-time.  I’m sorry about that. What I would like to impress on you is that I take this very personally, and take the necessity to provide a good service for your hard cash very personally, and in cases like this, I really feel I’m _not_ giving good service. It’s disappointing, and disheartening, and makes me sad and anxious.

I’m not blaming my suppliers of course, I’m sure they have their reasons for the delay, and assume they are just as invested in keeping me happy as I am in keeping you happy. The solution for me is unsurprising, and more frustrating because of that – just add a healthy margin of error onto expected shipping dates. That’s what I’ll do in future, again.

I’ve discovered that achieving consistency in a service is a much harder thing than achieving consistency with a pen, on a page. That’s something that I have a much clearer understanding of now, but it is surprising to me that having an understanding of the problems is only a very small part of providing solutions to those problems.

In other news, I have a big pile of _everything else_ sitting around, looking forlorn.  That is what passes for good news at this juncture.

Polargraphs, finally go again!

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After a long wait, Polargraph machine are finally available for sale again!

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http://polargraph.bigcartel.com/

I am pleased with the last batch of Polarshields I had made, so I’m waiting for a Big Batch coming in the next week or so, and I already have all the other stuff I think.  But in the meantime, I am taking orders – I find having the anxiety of holding onto peoples cash focusses the mind wonderfully.

 

New boards, and hack circus

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Ha, so the good news is that I got the fixed v1.5 Polarshields back, and so far they are looking good.

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Not properly tested the motors yet, but so far, so good.

I’m going to be away for a week though so I am not going to have much time to work on this.  One of the things I’ll being doing next Sunday is showing a different project at a Hack Circus event in London.

Linear Clock is like a circular clock, but unrolled.  It’s a project from a while ago that I recently revived, and I’ll be doing a show and tell.

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That’s Sunday, 6th of October, between 2 in the afternoon and 6 o’clock in the evening. It’s in the back bar of the Star of Kings pub, Kings Cross, London.  Tickets can only be bought ahead of time at this site, and I think it’ll be a lot of funny, as well as jolly interesting.

Please come along and see what happens, if you like technology, speculation, funny things, theremins, the phenomenal Sarah Angliss, or chat with brainy folks.  It will be lovely to meet you.

New boards No.

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So I was excited to get the sample for the “final” version of the polarshield v1.5 through today, very nice… Except I noticed it only had traces on one side of the board!  No traces on the bottom!

Hm.

To have a board made, I produce a bunch of files, each one containing information about one layer of the board – silkscreen printing, soldermask, copper traces, cutting outline, drill holes etc – and zip them up (they’re also on github).   I raced to check the files I had sent, and – crestfallen – spotted that I’d somehow managed to miss the bottom copper files.

Infuriating! The wasted money stings a bit, but the main penalty is that production is knocked back another two weeks, and it’s already been too long.  I’m getting anxious, and making stupid mistakes like that really doesn’t help.

 

New boards ho

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Well that’s a nice surprise – the new v1.4 boards work!  I shouldn’t be surprised I guess, since they are just the 1.3 boards with less stuff on, but it’s always nice when something just works.

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I had a thought when soldering this up though: Because the pins for motor A protrude through the board, they need to be filed down and insulated so that they don’t short against the housing of the USB-B connector on the arduino underneath (a blog about it).  This is a pain, and in principle (if not in practice), makes for a weaker connection.  This has never been a problem for building the full kit, because the arduino mega I use has a mini-USB connector, but for everyone else (and all the vitamin kit parts), it’s a glaring issue.

So I think I will swap motor A with motor C, so that by default, for polargraph, that filing doesn’t need to be done.  Will still be wise to put a bit of electrical tape on it because it could still contact, given the right pressure.

Motor C was added because I had the space, and also because I have a few plans for things that might like to have a third axis of control.  The parts for motor C will be unpopulated by default, for Polargraph products anyway.

So, I think I’m immediately going to revise this to swap A and C, but also I might try to move the servo and endstop pins, and add some more lights.  I’ve got all these LEDs to use up!

Another fortnight for v1.5.

Studio tenants show on this month

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The building where I have my studio has a exhibition of work on all through August, so I’m in it too.  I’ve got a cabinet of jewellery and a polargraph drawing!  Why don’t you come and see it?

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My photograph is dismal, the reality is better.  I might have some live drawing at some point, but I failed to move fast enough (and ran out of parts) to get it sorted out for the launch.

I’ll be at the preview tonight, Friday 2nd of August at Arts Complex, St Margaret’s House, 151 London Road Edinburgh EH7 6AE, but the show runs all month, and there’s three massive galleries of stuff across a range of budgets, so call in. My stuff is in Gallery 3.

If you want to come down, drop me a line and I can come and meet you! And show you some other stuff if you want to see it.  Or not, if you don’t want to, that’s fine too.