richard

Maplin geiger counter

Maplin published a design for a Geiger counter a year after the Chernobyl explosion in the September 1987 issue of the Maplin Magazine. I bought the kit for the remote head and constructed this. I never built their meter, because I used two CD4017 decade counters to make a faux dekatron display, feeding the output of the chain into a mechanical counter bought from H.L. Smith in Edgware Road in the early 1980s. Edgware road used to be a haven of weird and wonderful surplus electronics shops.

I’m not really sure why Maplin didn’t go the counter way, it’s not like seven-segment LED displays didn’t exist then. The dekatron display is better than a digital count for the first couple of digits, because the spin of the display gives a feeling of count rate, in a way that changing digital display numbers doesn’t.

The kit was shockingly expensive at the time – the Maplin Magazine shows the kit was £79.95 in 1987. That’s about £221 nowadays. Perhaps markups were much better in Maplin’s geeky heydays, whereas now they are competing against Banggood and Dealextreme. The original schematic shows an oddball AG1407 GM tube, it looks like I couldn’t afford the kit when it came out and built it in the early 1990s, when they had substituted the LND 712 tube, which is still made, LND 712 datasheet here. Datasheet seems to indicate 6E-5 R/hr for a count rate of 1CPS for Co60 source, so a conversion 0.0036R/hr for 1CPM

Olympus LS-14 clock fix

When I bought an Olympus remote control to reverse-engineer the Olympus remote control code, I got a Olympus LS-14 for £30. I’ve had a LS-10 for donkey’s years, these are reliable. However, the RS-30 is £60 and there was a LS-14 with RS-30 on ebay for £90. The LS-14 is a nice machine, key things that it does better than the LS-10 are a pre-roll buffer and the sound is a little bit more natural from the mics, where the LS-10 could venture on the tinny side.

It can also sample the first 12 seconds of sound to set recording level, should you lack the smarts to be able to learn how to set record level yourself 😉 No automatic recording level setting has ever been made that works properly, although the smart recording feature will work fine for a band running a sound check in the first 12 seconds, it leaves record level alone after the initial sound check. The feature is about as useful as a chocolate teapot on unscripted field recordings and wildlife

The clock on my LS-14 wouldn’t keep time. Indeed, after a couple of days I’d turn it on and it would invite me to set date and time. That’s easy enough to do, but irksome to do regularly, and usually means the lithium clock backup battery is shot.

Manufacturers do clock backup in various ways – some use a lithium primary cell, on the principle that planned obsolescence means you should have changed the device out in three years. You throw it away and buy a new one. Others use a supercapacitor, charged from when the device is switched on. That works well, these have a service life of about 10 years, you can buy replacements on ebay. Some use a rechargeable lithium cell, again these have a ten-year plus lifetime.

Nobody else seems to moan about the clock needing resetting on the LS14, so Google was not my friend in this case. I suspect mine had been in storage for a while. There was something about the seller getting this for his daughter to use at uni and it didn’t work out. Perhaps he left it in the garage or a shed in the damp. There’s not much else made of mild steel in the LS-14 to compare.

Dismantling the LS-14.

Take the three screws out the back. You do not need to remove the screws on the microphone housing. To get at the battery sadly you will need to take out the little board at the very back. It has a plug on connection to the main board, use your intelligence and ease this off. I had to unsolder one of the main battery connections. You will be presented with the main board, and the offending article can be seen here.

You can see that the battery is rusty as hell. Couldn’t decide whether the chemical splurge was the flux from the solder or some battery catastrophe. It was stiff like flux, whereas battery ooze usually wipes off.

The battery looks like bad news, particularly as I have not managed to determine the type or a replacement number. Probing with a multimeter showed it is charged to about 3V when the unit is powered.

Since I didn’t know what sort of part this was – rechargeable battery of supercap, I had a go at it with a fibreglass pencil to clean off the rust. I’ve had this experience with watch batteries – if you have one leak in a watch you have got to get all of the gunk out of the battery compartment, else you will find replacement watch batteries only last a few months before dying. That means either a special type of watchmaker’s putty, which is the right way to do the job, or q-tips and isopropyl alcohol. This is a less critical case than a watch. I don’t mind resetting the clock after a few months of non-use, it is resetting it after less than a week that hacks me off. I figured all that rust was possibly giving a high-resistance leak across the battery shortening battery life.

Luckily for me, cleaning all the rust off this was a win, the clock keeps good time and lasts over a couple of weeks still ready to be used again. So if you have trouble with the clock needing resetting in your Olympus LS-14, give cleaning the battery a go. I needed a replacement for my trusty LS10 which has been claimed by another family member, so fixing this means I have a useful upgrade now.

Knud Viktor’s remarkable sound paintings from 1977 released

The Vinyl Factory has released Knud Viktor’s sound paintings– featuring creatures from the Luberon in France

The sounds are sparse, opening with a nightingale, but the sounds work into a fine narrative. Towards the end of the first track there is a great mix of some fellow moaning out into the night against a nightingale and the humming of bees

Harassing hounds

This pair holler at everybody walking down the footpath by the side of the house. At least there’s a tall wooden fence at the front so they don’t go off at people walking on the main road. The dogs seem to be triggered by sight rather than sound. There’s a little growl on the in-breath that gives me a feeling of aggression behind the yap.

Unusually for a soundmark, they are reactive to a listener’s presence.

Maplin once supplied geeks with geiger counters and laser tubes rather than overpriced Chinese tat

Back-from-the-dead supplier of marked-up Chinese tat Maplin started life out as a supplier run by geeks for geeks, with a wide range of electronic music modules and later on projects which didn’t have any real use, but were technical curiosities.

Maplin sold a lot of Geiger counter kits in the years after Chernobyl. Mine is still in service, I vaguely seem to recall the tube was a ZP1401 with the thin mica window. It saved me a radon survey –radiation is a problem in the south-west with radon leaching out of granite underground. The Geiger counter reads lower in the basement than on the first floor my old house (Maplin’s tube was a mica-window type). Interestingly in 1996 Maplin magazine claimed that the prototype of this detected the Chernobyl cloud passing over Britain.

Another story behind the scenes was that during the testing phase of the Geiger Counter project, the normal background radiation readings rose significantly, these were recorded for prosperity on a printout.We later learned of Chernobyl, the world’s first major nuclear accident. It was detected here first at Maplin [^1]. The implication of this is that the radiation cloud passed over Britain, and not just contaminating the hillsides in Wales.

The display is styled after the dekatron counter tubes in my school’s Griffin and George Physics lab Geiger counter

In rural Wales you still need an AM radio, until the last tube fails in service at Droitwich

We used to match the medium to the message and the terrain, but now we seem to assume mobile data is everywhere. AM radio is dying, because everybody is online. Except when they aren’t.

I recently went hillwalking in Wales, and it’s handy to have the weather forecast, and FM doesn’t really happen in remote Wales. I was lucky enough to still have Radio 4 Longwave reception on 198kHz, but I was surprised at how quickly FM became useless in Wales. RDS doesn’t really help because the problem is there is no alternative signal to switch to in a lot of Snowdonia. There’s no useful mobile signal in a lot of mid-Wales either – I have a dual-SIM dumb mobile (which ahs better RF performance than a smartphone), on the O2 and Virgin networks for diversity of networks, and that doesn’t get anything in large parts of the hills.

Cuckoos, Lake Vrynwy

Lake Vrynwy is a RSPB reserve which has a lovely ambience and little noise pollution. Geese and cuckoos in the morning, from the south side of the lake

AT8022 XY

birds and sea from the cliffs overlooking Beer beach

The South-West coast path takes you high up on the cliffs overlooking Beer beach. A robin was signing, with a background of crows and the waves from a distance.

Binaural, OKMII

Scorhill Stone Circle panorama

I wanted to try out panoramic photography at Scorhill stone circle near Gidleigh in Dartmoor as well as tinkering with radio. I didn’t have much time there, it’s a tough drive through winding roads and Google maps had already warned me that I had about an hour on site tops if I wanted to make a meeting in Exeter in the afternoon. It’s worth a rematch, because there’s quite a lot of interesting stuff within a mile, what with the Shovel Down stone rows and possibly another circle to the northwest.

A long time ago I had ambitions to take panoramic pictures of stone circles. The moving panorama thing really sings with megalithic stone circles, they don’t move so much so you don’t need video for the immersive experience, and we have 900 stone circles still extant in the UK, mainly in the west of the country. Those were the dotcom days of Apple QTVR and plugins, and hardware that was only just up to the job. QTVR is pretty much dead now. Backwards compatibility isn’t really in Apple’s DNA. The problem with QTVR was these had to be encoded in that format, because computers weren’t hard enough to do the processing of the source file on the fly like Panellum does. So these images are lost in Apple-history-land, although the source files I do have show just how poor digital cameras were¹ in the 2000s, the pictures won’t particularly benefit from being QTVR un-munged and re-munged to whatever is the panoramic tech of the moment. On the plus side, the stones are still there so a reshoot is possible 😉

Panoramic photography images are big – the panorama is 1Mb in size, so I’ve put it after the read more break. They aren’t as big as John’s trig point images, but the great advantage of a stone circle is that all the action is in the near field, you don’t have to zoom in so much.

dogs and dappled light

I shot these pics raw, because there was a weak sun through the haze, so I thought I could push some of the shots, However, the weak sun came through dappled cloud, and Sod’s law seemed to say that in one direction the cloud closed in again just as I passed the same direction the second time². I have a Kaidan Kiwi-L and it is sweet, compared to trying to spin round a stone circle on a monopod with the integral level. Some of the win is that the click stop forces you to take enough pictures, and you can mount the camera vertically. There are much cheaper ways of doing this now – well, after you have amortised the cost of the 3D printer.

Kaidan made a big fuss of how you should adjust your camera so it spins around the nodal point, and early software used to be critical on that. I do still try and match that, but either Autopano Pro is a lot less critical of getting that right or I have become a slovenly panorama maker because it seems less critical now. With a stone circle much of the action is at a reasonably constant distance from the lens and the foreground is often miscellaneous grass so maybe a bit of parallax error in the foreground isn’t seen so much as when doing a panorama in a building, with all its straight edges calling out a poorly centred camera.

Scorhill has a lot of human traffic – dogwalkers abound, and I waited about 10 minutes while a lady did her callisthenics in the stone circle. This shortened the photoshoot, I just about took the Kaidan twice round the circle in varying light before some more hikers with a huge hound hove into view and I figured I needed to clear site to head off to Exeter. I could push the exposure for the darker pics, but the problem is the light is different as the sun went in, so they don’t match well.

lighting for panoramas

I need to think differently about lighting for panoramas, since they’re inherently more tricky. You can’t keep the sun behind you with a panorama by definition, and the golden hour is also not ideal. What looks great on a still in one direction will be the sun low in the sky and great big long shadows in the other. Exposure is easy with an overcast sky, but that sky is so boring. It’s probably safe to say too much contrast is a problem in panoramas, because many of the photographer’s tools to minimise it can’t be used through 360 degrees

Probably the best light for stone circle panoramas is a blue sky with plenty of fluffy clouds, one of which is over the sun for the entire duration of the panoramic spin. Panoramas may be more suited to the mid-morning and mid-afternoon, a little bit off the ghastly high-contrast sun overhead at noon time and get some shadows to give modelling but before shadows get out of control.

Look ma, no Linux

Getting away with modest zoom ranges is just as well, because you seem to need Linux to run the splitting program generate.py to get multiresolution images. I don’t have a GUI on my linux box and have already had to rebuild it three times when some software digs itself into a hole I couldn’t get it out of. So when I spot requirements like so

To be able to create multiresolution panoramas, you need to have the nona program installed, which is available as part of Hugin, as well as Python with the Pillow package. Then, run

I think, right, move along now, nothing to be seen here…

When I tried Hugin years ago there was some hoohah about the patented SIFT algorithm, so you got to manually select the tracking points, involving lots of swearing when it didn’t work. Life is too short for that sort of thing.

So I bought Autopano Pro, and they were nice enough guys to trace my license key even though 11 years have passed and I have a new email address, so that is how I process my panoramic images. Kolor is now closed.

It appears that the SIFT patent will expire next year, which is good. Software patents suck. If they exist at all, they should be on a much shorter scale – software and Internet time is shorter than dog years so a maximum term of five years would let you get dominance without jamming progress in a field for over twenty years.

Continue reading “Scorhill Stone Circle panorama”

Sainsonic AP510 APRS tracker experiments

I bought an AP510 some time ago, at the time results were disappointing, but the firmware has improved over the years. Using 20141215 I was getting signals out to about 8 miles from the typical white stick omnis like Diamond X50, and up to 20 miles from near Chagford on Dartmoor when it was mounted in a backpack. As you can see from the header picture, I had a great RF takeoff and not much vegetation in the way from pedestrian height 😉

Thank you G6SQX and G0MAS for running high performance APRS IGates! The difference in performance with the antenna taped to the fibreglass shell at the back of my campervan is visible in the paucity of reports near G0MAS around Uffculme, range was only a quarter of that as a pedestrian. Despite having steady power and a USB lead as a counterpoise to the aerial. Maybe taping the aerial to the fibreglass detuned it, this thing is marginal enough at 1W output.

My track and the stations G0MAS and G6SQX it reached

Some of the idea of getting this was to play with radio on the hills so it’s good that it performs better in pedestrian mode. I’d like to have a better feel of why exactly that was.

Continue reading “Sainsonic AP510 APRS tracker experiments”