On my day off on Thursday I went on a long and hilly walk. I fancied a change of scenery, so I searched for “walks near London” and stumbled upon a walk up and around Box Hill on a very useful and comprehensive website. I chose the circular route and headed to Waterloo to take the train to the unusually-named settlement of Westhumble.

The walk worked out to about 13km with over 300m of climbing, some of it quite steep. Box “Hill” feels more like a mountain in places, with slopes of 25% or more. It was made harder by the fact that the steps on the ascent are in the middle of being renovated, so some of them are currently just empty wooden frames around which you have to step.

The morning was the hardest part, and I enjoyed a pub lunch and a pint of local beer before the more moderate effort (about 100m of climbing) of the afternoon. I made it back to the station just as the single hourly train was pulling away, and was obliged to wait in another pub with a different pint of local beer, which was of course a great hardship. I think I earned it.

Even though the train journey takes the best part of an hour, Box Hill isn’t actually that far from London. It’s close enough to be served by at least one London bus (the 465), and yet the view from the top is very much not urban. It’s not a natural landscape – it’s as obviously shaped by humans as most of southeast England – but it is a mostly green one without a lot of concrete.

A view from Box Hill. Farm fields are visible in the middle distance, with a few cows that look the size of ants. beyond which the view is mostly trees with glimpses of fields between. The sky is blue where it isn't filled with fluffy white clouds.https://images.po-ru.com/original/box-hill-view.jpg

I saw a common chiffchaff while taking a rest on the walk. They may indeed be common, but you don’t see them round our way, and I hadn’t seen one before.

The saga of my feet continues. The skin is now almost completely back to normal, and, indeed, was perfectly fine with a total of about 17km of walking on Thursday. My heels are now wonderfully supple, as if they’ve been really well exfoliated, which I suppose they have.

But a less welcome effect appears to have been that my toenails didn’t grow properly for a short while. This part is now beginning to emerge from under the cuticle as a section of nail that’s significantly thinner than the rest. I’m concerned about what that’s going to mean as they grow out.

I scratched a Rails app maintenance itch and learned about tree-sitter and its query language in the process. It all started when I was working on an absurdly long test file written using Shoulda Context and struggling to work out where I was within the nested contexts. I recall that Shoulda was popular once upon a time, but nowadays it mostly makes me pine for the better tooling, ergonomics, and all-round developer experience of RSpec.

But pining doesn’t help me when the thing I have to work on uses Shoulda, so I set out to see if there was anything that would help me navigate the test layout in Neovim. This led me to the Aerial code outline browser, which uses the tree-sitter implementation built into Neovim to query the document. It understood normal Ruby code and RSpec blocks, but didn’t know anything about Shoulda. I was able to add the relevant methods, submit a pull request, and it’s already been merged. As a side effect, I fixed a bug in the RSpec implementation, so everyone’s happy. Or at least marginally less frustrated.

I had a good day of fixing electronics on Sunday. I repaired a couple of broken devices I’d picked up on eBay. The first was an Ibanez PD7 bass overdrive pedal. There were two problems with it; the most significant was that a diode had failed short across the power input. I replaced that with a spare from my stocks and cleaned the contacts in the intermittent footswitch. While I had it apart I cleaned up the filthy enclosure with a bit of cream cleaner and an old toothbrush.

It now works perfectly and sounds pretty good, for a total of 1.4p of components and a few pennies’ worth of cleaning products on top of the £20 I paid for the pedal. They go for £90 and up when they work (second-hand, because they’re long discontinued) so that’s 1.4p well invested.

The main circuit board was very interesting: it has holes and tracks for a wide variety of possible circuits, but the silkscreen is marked only for the parts needed for the PD7, and only these positions are populated. From a 2022 point of view, where you can have PCBs made in a few days for a matter of pennies, it seems absurd to go to all that effort instead of designing a board for one single circuit at a time. But the constraints were different back in (I think) 1989 when it first came out, I suppose.

I also fixed a Zoom Studio 1201, a rackmount effects processor from 1997. The only problem was a broken three-way slide switch. I tracked down the original component, and found that it was both available and cheap – but with a minimum order quantity of 1,400 or so. I found another switch of similar dimensions, screwed it to the front panel, and wired it to the panel with some kynar wire (a.k.a. bodge wire).

Slide switches are some of the hardest parts to repair in old electronics. A lot of them seem to be assembled to order from a vast menu of possible combinations, which means that you can’t just buy one. And they’re quite expensive compared to silicon. It’s now cheaper and simpler to do a lot of this kind of thing digitally instead, which in turn means that even fewer switches are available as stock items.

Because the front panel is a plastic sheet glued onto metal, I was able to peel it back and countersink the mounting screws so that the repair is completely invisible. It’s a surprisingly good stereo effects unit for a total cost of under £10 including the replacement switch.

The most interesting things I found inside the 1201 were the eleven-way rotary “switches” on the front. They’re not switches: they’re potentiometers with eleven detents. You or I can’t buy these off the shelf, but if you have the order volumes to specify eleven detents on a potentiometer, it’s a lot less cost and wiring than an eleven-way mechanical switch. You wouldn’t find either in most modern designs, I think. The 1201 is a product from the boundary of two eras: the processing is digital, but the interface isn’t.

I’ve been drinking a lot of cold brew tea lately. Steep 10g of Darjeeling in a litre of cold water overnight in the fridge and it turns into a delightfully floral beverage with a flavour profile that’s quite different from normal tea made with hot water. I recommend it.