Journal Entries
Possible new lead
Posted May 16, 2005
With various people dropping out, leaving only 2, a planned digging trip in Wales yesterday lunchtime didn't happen.
After a morning spent setting up a new PC, the two of us decided on a quick afternoon tourist trip to check out the end of an old and abandoned cave dig. A draughting entrance led straight to a winding and often flat-out passage, which after various contortions reached a place where the passage twisted vertical, and it was possible to stand and look along a tight passage a few metres to the end of the cave. On the way in, I had felt distinctly claustrophobic in one section while waiting for D. to dig out gravel from a low crawl. It seemed the only real way to progress would be by opening up the entire passage, all the way back to the entrance, probably by taking a slice off the roof.
Apparently the draught is usually very strong in summer and winter, with the outward summer druaght sufficient even to clear fumes from 'chemical widening' fast enough to allow multiple excursions in a single day. Despite the day being hot, the relatively cool air temperature wasn't enough to drive a strong draught, yet even given that, the narrow passage did feel slightly airless.
While reversing out (the only practical way to negotiate the passage), I was surprised by a sudden feeling of cold air on my face a few metres inside the entrance. What appeared to be simply a few small gaps between fallen boulders to one side of the main crawl seemed suddenly rather interesting, though dark spaces visible could have simply been gaps between fallen-in-situ boulders. A short digging later, the manageable rocks had been removed to give a better view of an interesting lead.
Progress was blocked by a large rock (~150kg+) which seemed possibly to be supporting the slab that formed a section of the roof. Given the small size of the pasage to the entrance, the lack of manpower and tools, we couldn't do anything with it, so we went back to D's for a think.
Deciding on another quick trip, we collected various implements of destruction, and returned in the evening. One near-perfect and near-silent cap reduced the rock to a dozen chunks ranging from the easy to the just-manageable, and within ~15 minutes of our return, the ex-boulder was safely outside. The roof proved not to have been dependent on the rock, after all.
Beyond, the previously-seen small voids were found to be larger than guessed, and it appears we are in the top of what might have once been a reasonable-sized passage, though with in-situ boulder infill on a possible mud floor, and a dodgy, partly-collapsed bed of rock coming out of the roof in places preventing immediate progress. However, above the dubious roof layer, the next bed of rock is ~2m thick and quite solid-looking, so the lead is *definitely* mineable for the moment, and with the main draught being with us, it's a much better prospect than the end we had originally gone in to inspect.
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Latest reply: May 16, 2005
Digital shuffle month
Posted Apr 29, 2005
I have had numerous problems with my ISP/webhost/domain registrar, including an incident where
a) all my email names fell into the hand of spammers, including unguessable ones, *and* ones that had never actually been used and existed nowhere except on the ISP's servers.
b) other customers had exactly the same problem at the same time.
c) the only other customer of theirs I know personally had the same problem.
and
d) they denied it could possibly be their fault.
So, I decided to switch to soemoen honest and/or competent.
It seemed the best move was to transfer the registration and hosting away from them first, then switch to another ISP. A mate had started up a hosting company, so I decided to use him as the webhost/email provider, and use 123reg as the registration provider.
The first domain transfer (one of mine) was fine, apart from being charged £14 by my ex-hosting company for them to do a couple of minutes work. When I came to switch the second domain (my sister's), the muppets killed the website and mail before starting the transfer, but fortunately 123reg were excellent, and managed to recover the situation quickly, so the site and email were soon running smoothly on the new site. Sorted, though it does seem they may have billed me twice for the f*&^%d-up second transfer.
I then asked for a MAC code to allow me to switch ISPs without loss of service, but the *email* support person at F*****a told me he wasn't *sure* if he could give me one or not, but could probably mail me in a week, and if I wanted one sooner, I could ring the [charged-for] telephone support people, who *could* (probably) give me one.
My reply wondering how come I could get a MAC from their phone support, but not from someone on email support, presumably sitting in the same building, seemed to fall on deaf ears.
In any case, I should finally be out of their stinking clutches soon.
However, I got a mail yesterday from my mate telling me his hosting operation hadn't taken off, and was folding at the the end of the month (ie Saturday midmight), so I had to do a hurried search for a new hosting package and go through the whole site/email server setup and tranfer operation all over again (the second time in a week for my sister's site).
Also, my sister's PC has been unwell for 2 weeks - an initial apparent disk corruption problem in an uniquely sensitive system file which took the system down was seemingly recovered from by a little dirty work with the assistance of an old 'unofficial' version of XP I had lying around on a spare drive but subsequently has turned out to have deeper roots - there's a subtle hardware problem causing occasional data corruption that has eventually required the purchase of a new motherboard and processor (arriving next week) before it's even worth trying a fresh install of XP, or a recovery from the backup tapes.
It certainly has been a learning experience - from now on, I'm definitely going to do regular system drive backups of both my machine and my sister's to CD/DVD to avoid the hassle of recovery from tape.
My sister was fairly busy painting, so didn't *have* to use her PC for film-scanning or preparatory work for pictures, but it has brought home how much she relies on it, and so we'll probably get a multi-pronged backup/archiving strategy in place soon - using tape, CD/DVD *and* external USB hard drive, and possibly soem over-the-network backup between our machines.
I'll probably need to write a bit of code or a fewe batch files to automate things for her, but then I *will* get to use the shiny new external disk myself as well, and any similar future problem should be easier to recover from.
However, quite a bit of time has been soaked up, just at the point I was finally ready to start building some more lights. The new 'B17' design is now finalised, and working well in a demo version in my new headtorch - a ~£10 Petzl Zoom lookalike body with a £70 (retail) lighting unit sliced up and inserted inside. Possibly the second most expensive headtorch in the UK, but rather better than its competitor, just like it is underground.
I have definite orders for 2 units, and likely ones for 3 or 4 more, which is enough to fund the construction of a few speculative units as well. My unpaid promotional agent in the Mendips seems to be generating some interest as well - with luck, sales will soon follow.
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Latest reply: Apr 29, 2005
Mineshaft progress
Posted Jan 27, 2005
Without wanting to jinx anything, it seems we may have made a little progress in the North Wales mineshaft dig.
After removing several feet of domestic and farm rubbish and ~60ft of rocks and mud, we seem to have reached some kind of level (horizontal mine passage. It appears to run in two directions along the direction of the sloping vein (fault) that we have been excavating down. One way is currently partially blocked, but the other lead for 10ft along the vein, then turns 90degrees and runs for 10ft through the hanging wall (the overhanging face of the sloping vein), before reaching the top of an underground shaft 20-25ft deep, which we are yet to descend.
It seems possible that the miners reckoned it was easier or safer to mine the offset lower shaft through more stable rock to intersect the vein at a lower level, but we won't know about that (or the other horizontal posibility in the level until we return, probably on Saturday.
Fingers crossed.
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Latest reply: Jan 27, 2005
More electronics
Posted Jan 24, 2005
It seems my previous light design wasn't as ultimate as I had hoped.
Despite working fine in home-made light units (secondhand headset and cable, and cheap helmet-mounted battery case), some commercial setups using using swappable helmet-mounted or waist-mounted batteries can cause problems.
This is because the cable from the headset plugs into an external socket built into a battery box, and over time, the contacts in the sockets on some batteries can become corroded or slightly displaced to the point where contact isn't very good.
Just general moving around (let alone banging into cave walls) when wearing one of these setups can result in an intermittent connection. With regular bulbs in the headset, this makes the bulb flicker. When (like me) you use a microcontroller chip to control brightness levels in the lamp beams, having power randomly connecting and disconnecting can be a larger problem.
Even though strictly speaking, someone else having a bad battery connection isn't *my* problem, it could still be a barrier to them buying a lighting unit from me that isn't bad-battery-resistant, and it's an interesting challenge to try and make a digitally-controlled device as insensitive to constant supply interruption as a bulb is.
I have an idea how to tackle the problem. Since it can't just be a case of modifying the controller program unless I want to lose functionality, success depends on how much extra electronics I need, and whether I can squeeze them into an already small space.
Also, it's a little annoying when a commercial lighting system is in some ways less robust than a homebuilt one, and not possible to do much with if it does start to degrade. At least on my personal hacked-together system, if a plug fails on one of my battery packs, or on the end of my cable (mechanically well protected *inside* my battery box in any case), I can easily replace the plug with a new one for a minimal price. If the connection fails underground, I can still bodge something together that should work until I can get back to safety.
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Latest reply: Jan 24, 2005
Electronic constructions
Posted Oct 21, 2004
Having pretty much finalised my new kick-ass cave-light design, (high efficiency, built-in redundancy, variable power, twin Luxeon LEDs, wide and spot beam, simple and advanced operating modes, etc.), streamlined the production process, and sold versions relatively cheaply to most of my closer caving mates (hoping to move into more profitable wider distribution soon), I'm trying to work out what to make next.
I started toying with a smart charger for cavelight battery packs, but got distracted into making a rough-and-ready amp-hour meter, since I have multiple uses for one, and it should only take a couple of days to knock one together. However, I can feel feature creep starting already on the amphour meter design, which is almost unavoidable given the possibilities opened up by circuits built round microcontrollers.
The cave light started out rather simpler than it ended up, though something I'm expecting other people (especially people I like) to rely on as their main source of underground light is probably better for the inclusion of the extra redundancy, and for some of the user-interface simplifications.
It *would* be great to have a battery simulator that I could use to check out the lamps - being able to fast-forward and rewind in time to the voltage/internal resistance performance of multiple battery packs could be even more useful than the amphour meter, but a bit more complicated to make, and it would really require the existence of a simple datalogger to use to record voltages and currents over time.
A datalogger would make testing virtually all the other things easier, but would probably be trickier to make than all the other things I want to build at the moment, and is probably something best worked up to gradually.
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Latest reply: Oct 21, 2004
Potholer
Researcher U92580
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