Subscribe by feed (RSS) LTM on Twitter and Facebook Urban Farming in the 1600sFrom the 16th to the 20th century, urban farmers grew Mediterranean fruits and vegetables as far north as England and the Netherlands, using only renewable energy. How to build a low-tech internetWe don't need 5G. We need a resilient, community-owned internet that uses less energy. Restoring the Old Way of Warming: Heating People, not Places Insulation: First the Body, then the House The Revenge of the Circulating Fan Back to Basics: Direct Hydropower Medieval smokestacks: fossil fuels in pre-industrial times Wind powered factories: history (and future) of industrial windmills The bright future of solar powered factories How to downsize a transport network: the Chinese wheelbarrowFor being such a seemingly ordinary vehicle, the wheelbarrow has a surprisingly exciting history. This is especially true in the East, where it became a universal means of transportation for both passengers and goods, even over long distances.
The mechanical transmission of power (1): Stangenkunst The mechanical transmission of power (2): Jerker Lines Systems The mechanical transmission of power (3): Endless Rope Drives The sky is the limit: human powered cranes and lifting devices Firewood in the Fuel Tank: Wood Gas VehiclesWood gas cars are a not-so-elegant but surprisingly efficient and ecological alternative to their petrol (gasoline) cousins, whilst their range is comparable to that of electric cars. If we insulate our houses, why not our cooking pots? Well-tended fires outperform modern cooking stoves The forgotten future of the stationary bicycle Bike powered electricity generators are not sustainable The short history of early pedal powered machines High Speed Trains are Killing the European Railway NetworkHigh speed rail is destroying the most valuable alternative to the airplane; the "low speed" rail network that has been in service for decades. How to make everything ourselves: open modular hardwareConsumer products based on an open modular system can foster rapid innovation, without the drawback of wasting energy and materials.
The parts of an obsolete generation of products can be used to design the next generation, or something completely different. Power from the Tap: Water MotorsJust before the arrival of electricity at the end of the 19th century, miniature water turbines were connected to the tap and could power any machine that is now driven by electricity. Aerial ropeways: automatic cargo transport for a bargainBefore the 1940s, aerial ropeways were a common means of cargo transport, not only in mountainous regions but also on flat terrain, with large-scale systems already built during the Middle Ages. The velomobile: high-tech bike or low-tech car? Electric velomobiles: as fast and comfortable as automobiles, but 80 times more efficient Some articles have been translated into French, German, Spanish, Italian and Dutch. Another Trains creation, featuring a rotary dumper automated using SBrick Plus and a conveyor belt loader automated using Technic Control Center. Power: electric (Power Functions / Technic Control Center / SBrick Plus)
Weird as they may seem, rotary railroad dumpers have existed since 19th century. Modern versions usually process the entire train car by car, without the need to uncouple cars, as the pivot point goes right through the couplings. Some versions can process two or three cars at a time. I’ve seen one such a mechanism in action a few years ago and wanted to build it ever since. When the LEGO 42055 set was released with new annular gear ring pieces, I saw it as my chance to do so. My rotary dumper could accommodate one or two cars and required the locomotive to be uncoupled manually. I’ve chosen this solution because the Lego train cars are very close to each other when coupled, and to rotate one without uncoupling would require fitting the ring gear with all the bracing within 1-2 studs wide space, or else the cargo would be dumped on the ring gear. Alternatively, the cargo bay on the car itself could be narrowed to create some “buffer space” on its sides, but since the cars were already kind of short, I didn’t like this idea.
The key feature was automating the whole mechanism using SBrick Plus – a new version of the SBrick device, distinguished by its ability to work with LEGO WeDo sensors. Inside the dumper, there was a WeDo motion sensor which would detect a train car and start a sequence pre-programmed using SBrick Profile Designer. The sequence would run for a little over 1 minute and control 3 motors: one for driving the conveyor belt at dumper’s bottom, one for locking the cars and one for rotating the dumper. At the beginning and the end of the sequence there were pauses when only the conveyor belt would be running, to allow for manual decoupling of the locomotive at the beginning and for removing the cars at the end, to prevent the sequence from being re-initiated by a car still waiting inside the dumper. There was a minor problem with stopping the dumper, because it would not always stop with the tracks inside it perfectly aligned with the tracks outside. This could be solved by either finding a perfect timing for the rotation motors (which is unreliable, as it could be affected by e.g. weight of the load), or finding a way to safely block the dumper at its lowest position without damage (which was problematic since it was rotated by 2 significantly geared down PF L motors, and thus operated with enormous torque)
, or resorting to Lego Mindstorms and motors with rotation counters. Having an unloading mechanism called for another one that would load the train, so I’ve decided to try to recreate a mechanism I’ve once seen in a port cargo terminal. The mechanism included a conveyor belt that would dump cargo directly into ships’ hulls, and move from one ship to another along the pier while always staying aligned with its end above the ships. I don’t know how exactly it worked but I’ve reverse-engineered how I thought it worked. In my version, there was a single long conveyor belt section resting on two turntables. One turntable was located atop sort of a car which drove forward and backward along the train and it could rotate left or right. The other turntable was located under a cargo silo which fed the belt, and it was built so that it could rotate left and right, but at the same time the conveyor belt section could slide through it forward and backward. Thus as the “car” moved, it pulled or pushed one end of the belt section with it, forcing it to rotate but also to slide – when the “car” was near either end of the train, the belt section was forced to slide out to reach the train;
when the “car” was near the middle of the train, the belt section was forced to slide in as the distance between the “car” and the cargo silo was reduced. Note that I had to put two battery boxes on the car to make it heavy enough to pull and push the belt section without derailing itself. Alternatively, I could put it on some sort of a track that would keep it locked down and upright, but making it heavier was simpler. The loading mechanism was automated with the use of a LEGO Technic Control Center which has the ability to record a series of command and then to “play” it back. When the empty train arrived, I would only need to start the pre-recorded program and the whole mechanism would then proceed on its own. It was also possible to stop it at any moment and to control it manually instead – which I would sometimes do when the automated loading left some free room in the cars. Note that there was some spillage of the cargo while loading, due to imperfect alignment of the conveyor belt’s output end above the train.