THE SHOLLEY PROJECT

I have a shopping trolley. It is made in Germany and quite good, it has lasted me several years of weekly shopping trips during which I would push it to the mall and shop and then push it home full - and over that time I learned that there are problems with the design – and since I could, I started designing my own to replace it.

Original model weaknesses

1. Front wheels are too small. Even a small ditch can stop the cart.
   

2. Bendy. Some would call it a feature but the plastic frame bends a little on uneven ground. I want something a bit stronger. I am concerned that this will eventually result in it breaking.

3. Folding. The current model has a lot of complexity and parts because it folds flat while I don't need that. Yes, it is nice but unnecessary.
   

4. Low ground clearance. When I  take it up steps the bottom gets scraped.

Basic Dimensions in cm:

length minus handle 64

width 54

height 84

ground clearance 8

main wheels 17

front wheels 9

upper bench height 57

handle overhang 23

Handle height 104

Bin internal 50 x 34 x 26

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DESIGN QUESTIONS

ONE: To fold or not to fold?

This is the big one: a solid frame is a lot simpler to make but not as useful.

I have designed a number of folding models but the existing model has almost never been folded. This, however, does not mean it will continue this way: I could in future move to a smaller place that makes folding necessary – but the complexity also brings weakness.

TWO: Stair Climbing

This means putting tri-wheels on the back - I would need to take these off an existing hand trolley. A useful feature as there are a lot of places where even a small step can cause a lot of trouble. The plastic trolley has its bottom gouged from these – the tri-wheels would not solve this but an aluminium frame will. Better ground clearance will help too.

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DESIGN VERSIONS

Version 10

This is based on the mostly plastic folding trolley I already have.

Version 30

Trying to make the lower tray accessible I split the tray. Not bad but I would need to find or probably make the split trays, not easy.

Version 40

Shifted the main wheels back to allow sliding the lower tray out sideways . This not ideal engineering wise however.

Version 63

This is the peak of folding designs – I even worked out a locking system for the front and back verticals. The down side? First, the complexity, second, the bottom tray has no protection against getting hit upward on bumps or steps. This was directly because I was trying to make it fold small and keep it light.

Version 67

At this point I was still thinking of folding it up and loading on the back of my bike so I put the folded design onto a virtual bike to see what it looked like and it looked bad. Clumsy and heavy.

From version 70 or so I decided to simplify and drop the folding aspect as it made things too complex. I also decided to add triwheels to make it easier to get up stairs and on and off public transport.

Version 74

The triwheels have arrived so here is the latest design with them as well as a solid (non-folding) frame.

This will make construction a lot easier and stronger but there is one down side: you can’t easily put brakes on triwheels. Still, this is looking the best yet. It is probably wildly overbuilt but as I don’t have FEA software I don’t care. It is made mostly of rectangle section alu with stainless steel bolts and nylock nuts. Brakes? Who needs them ! All of the parts are easily available and cheap enough - and now in my garage.  all that I need do now is get time and space to actually put it together.    Hopefully this will happen over the holidays. 

The TRX40 Build - Prices

 Purchase Date: November 2020

A major reason I decided to upgrade at this time was warnings from computer geeks that part prices would soon climb and that the shortages of parts would get worse.

This was highlighted by the GPU being $3000 and that was from a reputable supplier which listed several models of 3090 but could only guarantee supplies of one or two models.

I am still happy that I did get it though – it is the first computer that I am really happy with.

AMD TR4    3970X CPU (32Cores)                     $3279

MSI TRX40-PRO WIFI Motherboard                    $559

64 Corsair 3200 DDR4 RAM                                 $418

Corsair HX1200 PSU                                            $439

NH-U14S TR4-SP3                                               $159  (Special TR4 socket cooler)

Define 7 Compact Case                                        $199

Noctua NF-P12 PWM Fan x 3                              $147

Samsung EVO M2 SSD 500GB                           $145

EVGA RTX 3090 GPU                                       $2999

Samsung NVMe M2 2TB                                     $499

NF-A15 PWM Fan x 2                                            $98

TOTAL                                                               $9154

This was also my most expensive computer buy to date. I considered buying the AMD TR4 3990 64 Core processor but apparently Windows 10 does not run on it. Nope. You need Linux for that and I am not going to go there. Oh, and it cost $6000.

Looking at the same store now, the same model RTX 3090s are still available but now they cost $3600. All prices are in AUD.

This is all here for historical reasons: I am curious to see how this looks in future.

My new E- bike

I bought this to ride to work. My workplace is about 30 mins ride from home on my unpowered bike - fine, but when it gets late and I am tired I would prefer to not be getting so much “exercise” which is where this bike comes in.

From what I can find, it is completely road legal in NSW. It is pedal assist (you still need to pedal) and the motor is 250 watts and it is speed limited to about 25 KM/H.

I added a bell and a tail light to get it to road legal day or night – the headlight was already on the bike.

Although the front forks have suspension the rear does not so I bought a Suntour spring seat post which cost over $100 but it is well worth it. The solid tail on the bike means you can fit a carrier, which I have on order along with mudguards.

I also fitted a rear view mirror that fits on the end of the handlebars. This is a very useful item as it means you can see traffic coming behind you – I don't know why it is not a regulation.

At $1300, it is very good value compared to the assisted e-bikes for sale in other stores. It also a fat bike, that is it has big tyres and I wanted this because it makes the bike better for any offroad or rough surfaces. Oh, yes, it also looks awesome too.

You don't think it's such a good deal? Check out the common assisted bikes – they start around $4000.
I won't even mention the top prices, they are just crazy.
If you are good with spanners and wrenches it is easy to assemble and all the tools you need are supplied.
The only thing I did other than that was grease the chain.

I took it out for a 20 km ride today. Most of the trip was flat but there was a very steep hill at the far end – I could not have pedalled up that hill on my old 21 speed alu frame bike. Ever. The electric assist did it just fine.

There is one area of the bike that did give me slight reason for concern: the cables under the bike seem exposed and might get damaged during offroad riding – I might make a metal crashguard to fit there later on once my workshop is set up – but I am not expecting to go offroad so it is not a big deal for now. The front chain sprocket also protrudes well past this so in most cases it should protect the wires. 

I also considered adding turn indicators and the switch for them: chopping into the wiring loom is a serious matter and I am not in a hurry to do this - well, maybe later. It is still better than waving hands.

A special thanks to TDR Moto for the bike.  No, they did not pay me for this,  it's just a good product. 

If you want me, I'll be out every weekend, riding the city's bike trails . . . . 

ASSORTED WEIRDNESS

 

 . . . and finally, something on a more serious note. 

TRUTH FROM THE ROBOT REVOLUTION

 

THE DUST FREE COMPUTER PROJECT

 The main goal is getting the inside of my new computer as dust free as possible.

All of my previous computers needed to be regularly opened and the dust blown out, the earlier ones I even had to take them apart to do this and they had no dust filters. None.

Yes, you can buy filtered cases for industrial use but they are big, ugly and probably sound like a jet engine while my design needs to be very quiet and small – well, small enough to fit behind the monitor on my desk which has specific size limits since it is in a corner.

The previous PC (7980XE)  in place

As you can guess, I don't want glass doors, RGB or any bling at all either.

The new computer will be built in a case that comes with dust filters – but these filters are thin fabric mesh, only effective for larger bits of dust like hair – the fine stuff just goes straight through and there is a reason for that: the better the filtration, the harder the fans have to work to suck air through them.

None of the cases I have seen met my needs so I settled for the Fractal Define 7 Compact knowing that I would have to modify it to get what I wanted.

I found a review that suggested that there is not enough front air intake area in the Define 7 Compact case as supplied. Nobody mentioned the total lack of positive pressure though: it seems that other people don't care if there are gaps between the fans or if parts of the case block fan intakes. Some areas of the case have vent holes in places that make it look like the airflow can easily become circular! I am not going to have any of that though. The filter box will leave a gap at the bottom where air from the bottom of the case can be drawn in.

Original case front with fan mounts

My mods will not show outside the finished case and they should give positive pressure.

Please note that I am not complaining about the case: I am sure that Fractal made a good case, it is just that my needs are apparently a bit unusual.

THE CASE MODS

The design uses automotive air filters (the type used for cabin air, not the engine ones) which will be sucked on by three 120mm Noctua fans. Finding the right filters was a bit tedious since the measurements need to be close but I found something that will do. They are listed as “ Ryco Cabin Air Pollen Filter RCA294P fits Great Wall X200 2.0DT 4x4” and cost $45.90 AU for two.

Stage 1

To make sure the filtered air all goes into the case and provides positive pressure I worked out the places where the case needed to be sealed off and made patterns for the parts. I did this with cardboard and used sticky tape to hold them in place. 

 Above: Patterns fitted to case

There is the filter box, the lower air box which seals off the bottom of the case from the insides and two blanking plates, one to close the hole at the bottom of the door and one for the inside bottom of the case.

Stage 2

Next I got some ABS sheet off Ebay – this was not cheap but it is well worth it.

Since it was black I put masking tape over the sheets where I wanted to draw lines and then marked out the parts from the patterns I had made on the tape.

The back of the filter box was made of 5mm thick sheet , most of the rest were 2mm and the blanking parts were 1mm sheet.

To cut the back of the filter box I first drilled out the fan holes with a 115mm hole saw. This is best done first since if they are off or you get the plastic too hot it could ruin it. In a bigger sheet it will be more stable and easier to handle. Then I cut the outside shape with a saw.

The thinner parts were cut with a heavy craft knife – clamp a metal ruler over the line you want then cut repeatedly until it gets thin or the groove gets deep enough that you can crack it off. Sand and file everything to exact size and you are done. Note that cut edges will have a raised edge and a V shaped profile which is why you need to file and sand.

 Cut parts. 1- Filter box back, 2 & 3 - sides, 4,5,6 - Lower Air Box, 7 - Bottom plate, 8 - Door Blocker

Stage 3

I taped all of the filter box parts together with masking tape on the outside and checked that they all fit together nicely at the joins. Then it was a simple matter of running superglue ( I used Zap-a-gap) along inside the seams to stick them together. You don't need a lot of glue and it should run along the seams by itself, with a little help from gravity.

Once the glue was set I took off the tape and ran more glue on the outside seams now exposed.

Stage 4

While the glue was drying I got out my dremel- like device and suitably covered in mask, earmuffs, safety glasses and gloves, chopped the front of the case to fit the filter box.

Before I did this I took everything removable off the case as the metal and paint dust is the type of gunk that you do NOT want in a PC case. It took an hour or two and three saw blades but I kept at it and chopped the front out as well as a small part of the inside so that the filter box would go behind the case front plate.

After that I filed all of the metal edges as smooth as possible and then washed the whole case in lots of water and a cleaning rag to get all of the metal dust off.

This is crucial and I washed it twice as I missed some corners the first time. 

Front of case after cutting

 

Extra edge area that had to be chopped

Stage 5

I sanded the filter box to get rid of the glue lumps on the outside and taped it into the case and started fitting the parts of the lower air box to the case with more sticky tape, adjusting the part shapes until they all fitted neatly together.

Then it was a simple task to take the assembled lower air box parts out and glue them together as previously described. While that dried I worked on the filter box. I needed to add some supports for the filters and I had already drilled holes for some coathanger wire rods across the box for this purpose. I wanted to make sure the spot in the middle where the two filters met did not leak and I found an offcut of 5mm that fitted nicely there. I also made three small blocks of 5mm on the side of the box where it could be screwed into the case.

By using screws to attach it I could modify it later and it just looked neater.

Filter Box finished

Stage 6

The lower filter box needed finishing and a bit of reinforcement but once that was done and filed down neatly it all looked good. The bottom screw holding the filter box also holds on the lower air box. Originally I thought of gluing it all into the case but in the end I got some heavy black tape and used that to seal the air gaps and fix the lower air box to the case. 

Lower Filter Box

 

Stage 7

The door blanker was glued in, the big plate stuck inside the case with double side tape and then there was one last thing to do: The knobs that clip the door on needed to be shaved a little to avoid hitting the filter box.

Once everything was installed it looked good. I did not paint the cut areas of the case as it was more trouble that it was worth – this is not a display case. I don't expect the metal to rust as it should not get wet.

All parts fitted

After finishing the installation of everything and testing, it all works just fine, no overheating anywhere - but then I credit that to AMD making an excellent CPU with a nice big heat spreader and Noctua making a good cooler to match it.  The new PC has an AMD 3970 CPU and an Nvidia RTX 3090 GPU and it really is a big improvement over the old one. 

 

Everything installed