21 March 2025
by wpAdmin
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House of David

Since I’m enjoying another month of ‘trial’ membership of Amazon Prime (I imagine that enough people forget to cancel that they cover the costs of those who have learned the game of signing up every now and then), I am watching their new series, House of David. I don’t think it would be too far off to say that it is like The Chosen, except for being set about 1,000 years earlier. It does include lots of material from the Bible but it doesn’t necessarily shy away from adjusting timing, adding more detail and making it flow much more like a 21st century drama.

That isn’t necessarily a bad thing and they are very upfront about that, with a notice displayed at the start of every episode. If anything, I would say that, so far, it follows the biblical story more closely than The Chosen although (a) that isn’t a high bar and (b) The Chosen has four gospel accounts to weave together rather than the single core narrative of 1 Samuel. One thing that has puzzled me, though, is the suggestion that David was an illegitimate child of Jesse.

The Bible doesn’t hint at this but it turns out that some Jewish traditions get partway there. Mind you, the Jewish traditions also have David’s father, Jesse, as one of the greatest scholars and purest men of day and suggest that his great-grandfather, Boaz, died the day after marrying Ruth. I’m not sure they are necessarily any more historical than British legends of King Arthur and Robin Hood.

One thing that definitely doesn’t fit is the idea that David’s mother died when he was young – in 1 Samuel 22 he asks the King of Moab to look after his mother and his father (at risk from King Saul). So far (I’m up to the end of episode 3), House of David has only covered chapter 15 and about half of 16 and Jesse has already been a widower for many years. As with any historical drama, it is important to remember that script writers rarely let facts get in the way of a good story!

20 March 2025
by wpAdmin
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The Radius of Arcs

Today I have been revising how to calculate the radius of an arc. I’m working on a design for a printable widget that I can use to damp the strings of the various instruments hanging on my wall. I’ve had some foam jammed between the strings and the fretboard, which has worked well, but the foam is beginning to tear apart on the ones I use more often.

One thing I spotted after my first version was that instruments typically have a radiused fingerboard. Rather than being completely flat, the fretboard is like a small section (or arc) of a much larger circle. That is good for playability but makes for another factor to consider in the design. Given the width of the fretboard and height of the centre compared to the edges, it can be calculated with the formula h/2 + w^2 / (h*8) (as it is written in OpenSCAD). The revision was to remind myself of how that is derived – easy to look up online but worth spending a little while to understand.

Mind you, having printed a second test piece, I still haven’t nailed the fretboard radius of the electroacoustic bass in question. It isn’t entirely straightforward to measure the height element, even with vernier calipers. As another step, I’ve downloaded some radius gauges which I’m partway through printing. Of course, if they work, I won’t need to go the measure and calculate route directly although the maths will still come in useful. Even if I can gauge the radius by feel, I’ll still need to work out the height of the arc for the fretboard width in order to position things properly on my model.

19 March 2025
by wpAdmin
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Tomato Germination

I normally do pretty well with tomato germination but I can’t remember hitting 100% germination or getting those results in less than a week before. I think the difference has been the hot bath idea. That includes some seeds that were two or three years old. There is still a long way before they get the chance to become productive plants but it has been a positive start and I got all 32 seedlings potted up today – the next test is to see how they do now they have been moved from the heated area to a well lit spot (although still inside the house at this stage).

18 March 2025
by wpAdmin
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Too Tall?

I got a bit side-tracked in 3D design this morning, trying to work out some trays to hold seedlings. I had the bright idea of seeing I could make them tall enough to stack like modules on top of each other. The trouble was that trying to reinforce the top mean support material was called for (a waste of filament) and, going back to flat sides (no support required) was going to use a lot of material and take hours to print.

I think I might just go back to smaller, lower trays. Stacking up also has potential issues like reducing light at the lower levels or knocking over the stack. It was interesting to spend some time exploring but sometimes a bright idea isn’t the same as a good idea!

17 March 2025
by wpAdmin
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Why Lazarus?

The name Lazarus turns up in two places in the Bible. One is a friend of Jesus, who lived at Bethany and was the brother of Martha and Mary. We read about him in John 11 and 12 – he is the one who dies but then called forth from the tomb. The other is a character in a story Jesus told in Luke 16, about an unnamed rich man and a beggar called Lazarus. Actually, the rich man is sometimes called Dives but that is from the Latin translation and is simply the Latin for ‘wealthy’; in modern English, perhaps we should call him Rich! Lazarus, or ‘Lazaros’ in the original Greek text, is believed to come from the Hebrew name Eleazar, which means ‘God has helped’. Old Rich certainly didn’t extend any help in that direction but, when they die, Lazarus finds himself comforted by Abraham while Rich is in torment.

In the Bible study we attended this afternoon, we pondered the question of why the beggar character was called Lazarus. Further research online says it was a common name in 1st century Judea but that argument is typically backed up by citing the friend of Jesus and the fictional beggar. I can believe names like Mary or Simon were common, because we find multiple real people called by them in the New Testament, but I’m less convinced about Lazarus and I can’t lay my hands on sources outside the Bible to take that further.

I wonder if the character was named because Jesus had a friend called Lazarus? The story probably comes before that Lazarus was raised (the latter not long before the ‘triumphal entry’, which we find in John 12 and Luke 19) so there could be an element of divine foreknowledge? It is certainly true that, with the benefit of hindsight, we can see the truth of the words spoken by Abraham (yes, definitely that Abraham although still as a character in a story) that those blinded by wealth wouldn’t believe even if they saw someone raised from the dead. Luke’s account shows that Jesus was telling the story to Pharisees who sneered at him and loved money more than the history of Moses and the prophets that they should have been experts in!

16 March 2025
by wpAdmin
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Wicked Madness

We had a couple of new songs at the Charnwood Symphonic Wind Orchestra rehearsal tonight. One was a medley of tunes from the band Madness. There is a fair amount of syncopation but it was a fairly easy read, probably helped by the fact that the pieces included were all “Top of the Pops” hits when I was at school and paying attention to the pop charts.

On the other hand, the medley of tunes from the musical Wicked was a bit tougher to follow and it definitely needs some homework from me. Possibly it is a bit more complicated but I suspect not knowing the tunes is also part of it so looking those up is the first thing I need to do.

15 March 2025
by wpAdmin
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Tuba Bits Holder

Last month I mentioned that I was working on a 3D design for something to hold the pipes and valves of my tuba so they can dry out but with less chance of mixing them up. The valves in particular will fit in the wrong slots but then you can’t blow through the instrument. Here is the finished result:

I don’t have a multicolour printer and, at the time I ran it off, I didn’t even have PLA filament in any colour other than black, so it was printed in that. It has worked well but the numbers were a little hard to read. Last night I applied some white acrylic paint and this morning I used Dremel-like tool to tidy it up, making them much clearer. The pieces have been designed to tessellate, with the large end having two spikes for the pipe extensions, a valve holder in the middle and then a spike to hold a spring at the other end.

Once the parts have finished drying, I’ll check the lubrication and then pop them back on the tuba, ready for some more practise.

14 March 2025
by wpAdmin
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X-X

I’ve pretty much given up on X (formerly known as Twitter). Fewer of the messages I saw were from people I know or am interested in. That was balanced by an increasing level of messages that were not just junk but brain-rotting sewage. It was the equivalent of going into a newsagents and find that contents formerly relegated to a dodgy corner of a high shelf were all over the place, even mingling with the children’s comics.

I had been accessing X on my iPad. A while ago, I put it off the main screen and then turned off notifications. Last month, I decided to delete the app entirely and I haven’t missed it. The poor little blue bird died a long time ago and I’d now count myself as an ex-X user.

13 March 2025
by wpAdmin
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Custom Clips

The hot bath for plant propagation that I mentioned yesterday was also another opportunity to do some more 3D design and printing. The heating mat only comes on when the temperature drops too low, which means I need a temperature controller (also part of my homebrew set up) with a probe in the water. There was a hole in the propagator lid but I didn’t want the probe running through that for too long as it was a pain every time I needed to take the lid off to check on the plants or add new trays.

The solution was to create a little block to sit on the side of the propagator at one end, propping the lid up and allowing the probe lead to flow through. My first design was based on a cuboid with a couple of other cuboids cut out from it. One resulted in a lip on either side, so it would fit securely on the rim, and the other ran perpendicular to the first, creating a tunnel for the lead.

It worked but had a few flaws. In particular, the weight of the lid pressing only on one side of the block made it feel unstable. I tried a second version with tweaked dimensions, including a long extension down the outside of the rim but it still wasn’t quite right and the overhangs I had introduced didn’t print perfectly. As I worked on the design, I realised I could simplify it into a single solid shape designed from the side and extruded to length rather than cuboids with cut outs. Version 2.5 was a thin variant of the hook design to check the dimensions. One was off and I decided to run another print of that with four slightly different variants.

Finally, I could print V3, the final one for now. The hook is long enough and flexible enough to go under the rim on the outside and resist the force created by the lid that tries to pull the block inwards. There is no cut away, meaning I can print it with one side flat on the build plate for a higher quality and stronger result. Finally, how did I feed the cord through the solid shape? Easy – I printed several of them to hold the lid up (strength in numbers) and the cord runs safely through the gap between them.

Better yet, the tomatoes have germinated pretty well and I think I can see signs of the peppers coming up so the design work is serving a useful purpose.

12 March 2025
by wpAdmin
2 Comments

Hot Bath

My homebrewing might have to take a break for a few weeks as I’ve pressed my heat mat into service to create a warm environment for germinating seeds that like a bit of heat, such as chilli peppers and tomatoes. Those often cite a range from 20-22°C. I’ve still managed to germinate tomatoes inside, even though the house is normally cooler than that but, this year, I’ve set up a large propagator with the heat mat underneath and water inside.

The heat mat keeps the water to about 21°C and then I can put plastic containers in that with compost or small pots. No sign of the peppers yet but the tomatoes are just beginning to show. I’m interested to see if it gives them a stronger start but time will tell.

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