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.

It’s such a good feeling when I put a new blade in, cutting like butter, and every time I do (every time) I reflect that I mustn’t leave it so long next time – the benefits of having the right tool for the job outweighs any notional benefit of being a cheapskate.

As with soldering.  I can do the surface mount stuff easily and quickly en masse, but I dread the through-hole stuff, the pin headers and sockets.  It just seems to take forever, and is a battle.

I looked at the iron tip, which has slowly been getting narrower and narrower.  It was initially thin to do 0804-scale surface mount soldering, but I now use hot air for that.  It’s no longer the right tool for the job, and it’s terrible corrosion makes it even worse.  I looked for a replacement, but remembered I had got a multipack of tips last time, containing a mixture of sizes.  Grumbling, I put the next smallest one I had on, and after the first joint, wished I’d done it months ago.

Bigger tip = more heat = quicker joints.  Obvious.

As an amateur, economy plays a large part in my reluctance to snap off a blade segment, or unwrap a new blade, and also storage and access (trying to remember where I put the spares months ago).

As a professional (which I suppose I am) I have to balance cost with speed and quality.  And as an employer (employing myself albeit) I have to balance cost with quality of life.

Right tool for the job.