Lessons in Rapid Prototyping and Design

Never before did I realise what a huge difference software and firmware can make to 3D-print quality.

Not long after setting my reprap up again in its new home, I found it having problems moving in the Z-axis, where the motors would refuse to move half the time, which after describing it on IRC people helped me figure out that the controller was telling the motors to accelerate too fast.
The acceleration that had been implemented in June 2011 Sprinter firmware still caused a significant amount of 'jerkiness' in axis movements. By updating to the latest version for June 2012, not only did more appropriate acceleration, adjusted by a predictive 'look-ahead' buffer, improve this current problem, but it also cut out a vibration problem that broke my Y-axis last year, by pausing at the end of each move for a few ms, when making very short successive movements in order to draw a narrow zig-zag fill line. This helps because in most stepper-motor use there is no feedback control mechanism - the idea being to move a set number of steps then lock in place and hope for the best, which in reality can result in nasty vibrations. By stopping for a moment, the transient vibrations resulting from overshoot can settle, so there is less chance of them feeding into some resonant frequency and shaking the printer to bits.

Illustration of overshoot, via Wikimedia Commons.

In the new firmware a minimum temperature is now set by default, which might have prevented another previous incident that I had with over-heating when a thermistor connection broke.

It Hits The Fan

Gardening in a region where you're almost always surrounded by sheep has its obvious pitfalls...
Sometimes those sheep or their mischievous little lambs find a way past the fences you put up, because they can see that not only is the grass greener on the other side, but there are also tasty things other than grass to chew on.

One or more of those sheep got over a fence recently and wreaked havoc among the crops I'd planted, trampling some while eating the tops off others...

They seem to love eating fiddleneck flowers

Confluence of Aspirations

On locally appropriate crops, some Alpine Strawberries that I planted out along the swale wall from pots are doing fine, and I hope to give them some rhubarb in between for company soon by separating some of the rhubarb that's already growing around here.

This Alpine Strawberry plant is just going through flowers and starting to grow fruit at the same time.

Flora and Fauna Identification in Sutherland

In this post I will try to identify many of the seedlings and volunteers/'weeds' that I have seen growing well around my local area in the cool maritime climate of Sutherland, around the North/West coast of Scotland. Your help is greatly desired, so please leave a comment if you have a clue! This post will be updated until I consider it reasonably complete. (Last updated 1/7/12)

As for local flora, daisies, dandelions, nettles and heather (all with edible parts) are so ubiquitous around grassy areas here that there's no point wasting a photograph on them. Seriously, this last month I've seen a whole sheep field turn white with daisies, mowed lawns shine bright yellow with dandelions, everyone on this island has probably seen how nettles like to take over any odd nook or slope where moisture gathers, and heather... well let me just say that every few years the sheep farmers set entire hillsides ablaze up here to get rid of the stuff after it has taken over; some of the current google maps satellite images for the region still show glowing patches and smoke clouds at low levels of detail.

Most plants here suffer salt-burn from the coastal winds if not well protected, especially trees:

This is a native Rowan tree, known for producing a quite tart fruit similar to cranberries only much more sour, typically used to make jellies to accompany meat, otherwise a great bird food when left on the tree. It probably prefers to be further inland though.

Sowing Perennials Indoors

Progress was slow over the last few weeks; I lost a lot of work time looking after a friend's hungry hair-generating quadruped for them while they were away (I'm getting a bit tired of the number of animals people feed with agricultural produce when this society won't even distribute it to all humans, can you tell?), but I have learned some more about what works in this region in the meantime.

Most of the fruit trees have started blooming, this damson tree was the earliest.

Did you say shrubberies?

As I mentioned a few days ago, the elaeagnus pungens shrub that I planted from a pot looked quite unhealthy, since most of its leaves were turning pale and some dropping off though it should be an evergreen plant. The hybrid Elaeagnus x Ebbingei from a pot was doing very well by comparison:

Although a few of the leaves were turning that same way.

A Brief Update

I hate moving house.

Some of the elaeagnus shrubs are struggling here.

Snow in April.

That is all.