RobjUK

That's certainly another approach, each sensor can stay on its default address that way rather than having multiple configs.

From the data sheet, it looks like you can use the CE (GPIO0) input to selectively power on the sensors, so each can have its address set before enabling the next one. You would need a few extra I/O lines - or a shift register and pins for clock & reset, to step through the enables to any number of sensors. Edit - note that you need to wait more than a millisecond after setting the enable high, before trying to access the sensor or reconfigure it.

An assembly video I watched for a different das87 kit showed them annealing a couple of brass parts with a gas torch, so they could be opened up and reformed around around other parts. Could that be what's needed with the final track connection?

There was an old manually operated crossing on a colliery line through farmland near where I grew up. Just heavy wooden barred gates, normally set across the "road" (farm track), that had to be swung inwards across the rail lines to allow a vehicle through, then moved back to their normal position. I seem to remember each side had a double gate, but I could be wrong & it was just a big single gate each side. Generally the layout was something like the one in these photos, over a double track. The photos are probably the era you need anyway: https://www.1900s.org.uk/images-1940s50s-level-crossings.htm Edit - I believe the gates on the one I remember were more this style: http://haylingbillyheritage.org/places/langstone/langstone-level-crossing-circa-1900-1914-from-the-roger-nash-collection/

I've seen quite a few where a strip of foam or possibly felt is used as an underlay below the track, but never any clay? The idea is usually to reduce vibration passed through to the baseboard, hence a slightly elastic material.

This place stocks some das87 stuff and they have a branch in Derby. Very good service! https://www.tiny4x4.com/shop/

They look to be spot on! I wish I'd seen them a couple of weeks ago.. Looks like a future project

I've gone with this idea, at least for now - but some Marklin E320552 HO wheels, 9.5mm diameter. They look relatively wide so hopefully they will run OK.

Those rechargeables are totally compatible with any properly-designed gear intended to work with dry cells. Although dry cells are nominally rated at 1.5V and give around that when new, they are not considered totally flat until they have discharged down to around 1V - so starting at 1.2 - 1.3V and down to 1V flat from a NiCd or NimH cell is absolutely fine, or should be. The problem arises when equipment makers skimp on specifications and do not design things to work over the full voltage range, so they pack up or show batteries being flat long before they really are. That's common problem with things using 9V batteries and 7805 type voltage regulators - the battery consists of six 1.5V cells and can provide power down to 6V, but the regulator does not work properly below 7V... Typical per-cell discharge voltage curve for dry cells - anything that cuts out at 1.2V is wasting a good part of the cell capacity:

Are you using a two digit or four digit address for the loco? CV1 is only used for short address mode; CVs 17 & 18 hold a long address, I believe. Edit - do you have a stay-alive connected? Depending how they are built and wired, they can bypass the motor current pulse used for feedback to the controller, as it's supplied by the stay alive and not the track connection.

Have a look at Hardy's Hobbies, especially the "Civilians" category. https://hardyshobbies.co.uk/product-category/civilians/ They are each available in multiple scales, eg. one figure at random: https://hardyshobbies.co.uk/shop/civilians/man-with-hands-in-pockets/ 1:43.5 is 7mm to the foot. You should be able to find a suitable figure that can be painted as appropriate?

Ouch - that's just a bit on the expensive side. It is probably Alu-sol, I've had a reel of that for decades & still got a good amount left. The flux reaction seems near nuclear, the solder will flow on aluminium without too much difficulty and such as stainless and piano wire are a doddle. It's not cheap, but a half kilo reel is about the same cost as four or five short bits off ebay: https://cpc.farnell.com/multicore-solder/629443/solder-alusol-0-91mm-500g/dp/SD00059 [Edit - RS have the same thing rather cheaper: https://uk.rs-online.com/web/p/solders/0555099/ ] My antique:

There are a couple of similar versions on this site: https://kslaserdesigns.com/O-gauge-Paving?product_id=249 https://kslaserdesigns.com/O-gauge-Paving?product_id=248 And some more types in the "pavement & furniture" section" https://kslaserdesigns.com/O-gauge And masses on ebay, though they are the US 1:48 version so about 10% smaller than 7mm scale would be. eg. https://www.ebay.com/p/15-Pcs-O-Scale-Model-Park-Benches-Platform-Settee-cb/1831289582

If you use superglue on small or detail parts, get some activator spray! That can be wafted over a glued part and causes the glue to harden instantly. Or you can apply a trace of that to one part and the glue to the other, causing it to set very quickly when fitted together even if it's not in an airtight location. The "Mitre fast" glue and activator kit is very good for doing small parts as it's also a thicker grade of superglue, rather than a water-thin type. Some builders supplies also sell the glue for that kit separately, as the activator lasts for several bottles of glue. https://www.toolstation.com/mitre-adhesive-kit/p47409 I put a drop of the glue on a bit of scrap plastic bag and use a wire offcut to put it on to small parts or build up joints. If using an activator with a different make of glue, test it separately first.. eg. I use the "pound shop" packs with ten small tubes of glue for a lot of things - but despite the information on the tubes claiming it to be exactly the same basic chemistry as the mitre fast one, neither that activator or a generic one has any effect whatsoever on it! As others say though - with metal parts, if it's at all possible, solder them.

Progress! The Barclay chassis is now finished, I believe! I just ran a 2.5mm bit through the holes in the links by hand, which removed a few traces of solder - they then have just a small amount of play on the crankpin bushes and run nicely. Those primed and painted and an extra coat on the chassis and buffer beams, then the buffers installed to complete it. Plus I've finally got around to buying the new mesh for the Deltic roof fans. The original woven brass mesh just looked wrong to me and I was not happy doing anything else on the body until that was changed. The new vent grids are etched nickel silver from the excellent "Main Line Diesel Locomotive Fittings Set" by David J Parkins: https://www.djparkins.com/product.php?productid=18234 They have a major effect on the overall appearance I believe. The fan & duct are just held in place on a fingertip for the photo & not quite perfectly centred, though now the parts are more visible it looks like the ducts need reprinting fractionally larger..

Hi, thanks for the replies. I have looked at various OO/HO wheels but not found anything that has the appropriate proportions. Bearings - interesting idea, they would need to be epoxied up on the driving axle, but definitely worth looking in to! I have been looking at model cars and found a couple of types, that are either suitable diameter or suitable thickness - but not both. They are also mostly aluminium, so difficult to work with. One of my last resort possibilities is some 1:87 cast brass ones I already bought on the offchance, with small sections of brass then mild steel tube soldered over them to bring the diameter out to 9.5mm or so. The wheels are only about 5.2mm diameter and 2.9mm thick... They would still need a flange adding at that, and I cannot see me getting all the parts true without access to a lathe. Another possibility is 3D printing, if any place does actual steel or something similarly strong; I've not really investigated that yet.

Hi, I'm trying to find a source for a set of four wheels approximately 9.4mm diameter. I've spent days searching and I cannot find anything this small with a suitable width for O gauge track. It's for something I've been considering for a while, just as something different (and something else to build) - a "Fairmont Speeder" rail car. The thread about the Ford railcar prompted me to actually have a go at it. The prototype wheels are 16" and look as if they are pressed steel. Or if nothing is available, does anyone know a place that will turn a set to specifications, at a sensible price? I'm not starting anything for this unless I can get suitable wheels, as those are the one special part I cannot make or modify myself. The rest of it should be an interesting challenge if i go ahead, as the space available for the drive system and decoder is tiny. [And it must have sound, the hit & miss engines are one of the most distinctive features of these.] A couple of prototype pictures, for reference:

I'd say they are 4.7uH chokes for suppression.For some reason axial style chokes frequently have a green body. Example: https://www.ebay.com/itm/100-PCS-4-7uH-1-2W-0410-Color-Ring-Inductor-4-7-uH-Axial-Color-Wheel-inductance-/302044857551

There are a few different variations here: http://www.train-tech.com/index.php/sound/scenic-sounds

Hi Michael, thanks for the comments. I've not locked one of the jackshaft cranks to the shaft yet, I want it to run free first. I think the links just need the holes opening slightly to allow a trace of movement on the compensating axle; they are a very close fit at present. The buffer beams have the rivets - see the photo after painting, copied below. I used the 0.55mm solder ball in the primer coat method I mentioned in one of my posts above; possibly a bit small for the buffer beams, but clearly visible. It's an experiment, they should be fine for the cab strips. This is an ebay listing showing some of the sizes available; 25000 per bottle: https://www.ebay.co.uk/itm/1-Set-Lead-free-Reballing-Soldering-PCB-Heat-Universal-Stencil-Balls-BGA-NEW/352428570625 I will remember the plastic padding trick though! Yes.. I'm not looking forward to that rounding-off stage... There does not seem to be much metal to give it such a large radius as the prototypes - do you fillet the inside to give more metal to work with?

Again not a Marshall, but a very nice looking O gauge kit: https://www.ebay.co.uk/itm/O-On3-On30-1-48-SCALE-WISEMAN-MODEL-SERVICES-J-I-CASE-STEAM-TRACTION-ENGINE-KIT/151408181953

The aluminium anti-solder barrier mentioned earlier, just before the parts were separated - and the assembled engine housing, The slightly out-of-line door was reset after I noticed it in this photo, and nothing screwed down at that point, the footplate and body are just resting in place. (I need to re-attach the control console, then I can realign the handrails that wilted during other soldering.) The third photo is my "rivet jig" - a couple of bits of B&Q steel bracket & G cramps, with some tiny recesses made with small drill bits and a pin vice, plus the sharp point of a needle file (tapped with a pair of pliers) to act as the punch. You can see the results in the engine housing brackets & general bodywork.

More soldering and the "centering" adapters on the buffer bodies:

I've been refining my brasswork soldering techniques ever since I started the Barclay - I first used a 150 watt iron for larger parts, which provides plenty of heat but is incredibly messy. You can see the results of than on any photos above which show the inside of the chassis. I now use my 50W Antex electronics iron for small parts, or a miniature gas torch. A combination of the gas torch and carefully applied traces of solder paste seem to work very well for near-invisible joints and I have used that method a lot in building the cab and body, where the joints and any excess solder are in plain view. The cab window frames and handrails in the photos above are good examples of that method, with very little other than occasional colouration beyond where the joint itself is. I used the same method for the engine casing and access doors etc. With laminated parts like the radiator, connecting rods and jackshaft weight etc. I again used tiny amounts of solder paste, plus metal bulldog clips to hold the parts together. I also used steel screws or the axle end etc. through any holes that needed to be aligned. For soldering the fixing nuts to the engine base & footplate, plus the body to the the base while attached to the footplate, I did not like the idea of greasing things as suggested in the assembly notes, it seemed likely to make further soldering later on difficult. I just put a tiny amount of 3 in 1 oil on each screw thread via a cotton bud before assembling the parts to solder the nuts in place. The nuts were soldered with a small iron and cored solder - and all the screws came out again without any problems. For soldering the engine cover etc. to the body base plate, I put a piece of aluminium foil over the footplate before screwing the body / cab base down to it. It ended up rather scorched, especially where I messed up and got one side of the engine cover out of line and had to use a lot of heat to separate that joint - but nothing adhered where it should not have. Photos - the "expanded" motor cut-out mentioned previously, then soldering bits:

I've made quite a bit of progress on the Barclay since my last post in this thread, though not without the odd disaster! The chassis is finished and painted, though needing another coat on the buffer beams and the edges of those touching up. The motor/gearbox, wheels and jackshaft are in. It's not quite as free as it should be, the alignment is not absolutely perfect - and as I've included the compensating system in the rear axle, I think the holes in the links are going to have to be rather a sloppy fit for it to run freely. The compensating system as shown in the kit assembly instructions made me cringe (Sorry Michael..) - as an engineer, having perfectly good brass bearing bushes then taking the load on the edge of a bit of sheet, is just wrong! I came up with a very simple mod to fix this; just a bit of loose brass tube cut to fit over the inner ends of both bushes, then a centre support for the tube to balance on - the load is then take by the bearings. When I first fitted the buffer beams to the chassis ends, they were around 3 - 4 mm too close together and did not match the footplate ends. I have no idea what I did wrong, but luckily I chickened out from using conventional solder for those, not wanting other parts to fall off in teh process, and used low melting point solder (for white metal). That allowed me to remove them again without causing any other damage, and I added some packings to both ends to get the size matched to the footplate. I fitted the buffer bodies to the buffer beams using the same solder. The bosses on those were rather smaller than the buffer beam holes, but a few turns of single strand copper on the boss made it a good fit, then squared across the top with a straight edge to set them square before soldering. I used plenty of 6% phosphoric acid flux and put rows of tiny solder chips against the buffer bodies, which worked pretty well. I have also done some rather more drastic butchery: The Canon motor body is just too wide to fit the footplate and body centre cutout, so after after soldering all the relevant I too a strip off either side of each cutout to allow it to fit around the larger (or rather differently oriented) motor. With some other slight mods to the chassis, I managed to fit that a lot lower in the chassis frame, giving a lot more room in the engine casing for electronics & speaker etc. The control console dropped off whilst I was soldering parts of the engine cover to the cab... That is still to re-attach. I've invented an alternate way of adding rivets? (I've never seen it, anyway). The Barclay was the first brass kit I ever started and I had no clues about detailing such models or pre-punching the etches for rivets, when I started the chassis. I did not punch any of the buffer beam rivets, they are just open recesses, the way I assembled them. I have learned a lot since then, but with my home made jig I'm still not happy doing very small parts that can bend easily, such as the rivet strips on the cab. So, I wanted something else to form the river heads on the buffer beams and strips. The answer is a load of balls - solder balls in fact, available in packs of thousands for a few pounds, sold for "re-balling" BGA typo integrated circuits. They are available in many fractional millimetre sizes. I got a pack of 0.55mm, £3.50 for 25000, I think it was. If these are added to the dimples where rivet heads should be, as the primer coat of paint is being applied so that sets them in place, the result is a perfect dome head! Possibly a larger size would have been more appropriate on the buffer beams, but I think they should be spot on for the cab strips, once I get as far as painting that. A few photos relating to the comments above, then a few more showing some techniques I use etc. in separate posts. I'm learning as I go so a lot may already be standard, but just possibly some bits may be useful to other people.