Commercially available radio control tanks are fun and all, but sometimes you’ve just got to build your own. [Let’s Print] did just that, whipping up a tank on his 3D printer before taking it out in the snow.
The tank is a fairly straightforward build, relying on a pair of brushed motors for propulsion, controlled by twin speed controllers hooked up to standard radio control hardware. Everything else is bespoke, however, from the 3D printed gearboxes, to the chassis and the rather aggressive-looking tracks. The pointed teeth of the latter leave deep indentations when the tank cruises around on mud, though weren’t quite enough to stop the little tank from getting high-centered in deep snow.
The build isn’t for the impatient, however. [Let’s Print] notes that the tracks alone took over 80 hours to run off in PETG, let alone the rest of the frame and gearboxes. However, we’re sure it was a great learning experience, and great fun to drive outside. Now the next step is surely to go bigger. Video after the break.
When I started writing this, there was a container ship stuck in the Suez canal that had been blocking it for days. Just like that, a vital passage became completely clogged, halting the shipping schedule of everything from oil and weapons to ESP8266 boards and high-waist jeans. The incident really highlights the fragility of the whole intermodal system and makes us wonder if anything will change.
Setting the Standard
We are all used to seeing the standard shipping container that’s either a 10′, 20′, or 40′ long box made of steel or aluminum with doors on one end. These are by far the most common type, and are probably what come to mind whenever shipping containers are mentioned.
These are called dry storage containers, and per ISO container standards, they are all 8′ wide and 8′ 6″ tall. There are also ‘high cube’ containers that are a foot taller, but otherwise share the same dimensions. Many of these containers end up as some type of housing, either as stylish studios, post-disaster survivalist shelters, or construction site offices. As the pandemic wears on, they have become so much in demand that prices have surged in the last few months.
Although Malcom McLean did not invent container shipping, the strict containerization standards that followed in his wake prevent issues during stacking, shipping, and storing, and allow any container to be handled safely at any port in the world, or load onto any rail car with ease. Every bit of the container is standardized, from the dimensions to the way the container’s information is displayed on the end. At most, the difference between any two otherwise identical containers is the number, the paint job, and maybe a few millimeters in one dimension.
Standard as they may be, these containers don’t work for every type of cargo. There are quite a few more types of shipping containers out there that serve different needs. Let’s take a look at some of them, shall we?
When it comes to dominating offroad performance, many people’s first thought is of tracked vehicles. Bulldozers, tanks and excavators all use treads, and manage to get around in difficult terrain without breaking a sweat. Today, we’re exploring just what makes tracked vehicles so capable, as well as their weaknesses.
It’s All About Ground Pressure
Let’s first look at how tank tracks work. There are a huge variety of designs, with differences depending on application. Different trends have been followed over time, and designs for military use in combat differ from those used for low-speed construction machines, for example. But by looking at a basic tank track design, we can understand the basic theory. On tanks, the track or tread itself is usually made up of individual steel links that are connected together with hinges, though other machines may use rubber tracks instead. The tracks are wrapped around one or more drive wheels, often cogged, which directly pull on the track. On the bottom of the vehicle are the road wheels, which ride on top of the track where it lies on the ground. The weight of the vehicle is carried through the road wheels and passed on to the tread, spreading out the load across a broader area. Outside of this, the track system may also have one or more idler wheels used to keep the track taught, as well as return rollers to guide the track back around without touching the road wheels.
For some, the idea of several hours of painting and designing intricate models with minute details and features sounds like a delightful afternoon spent. Some of us would much rather just have it come already painted with motors so that it can move. [Cory Collins] sought to combine these two hobbies by building a highly detailed motorized tank dubbed Tankbot 2.3. (Video, embedded below.)
It’s based on a simple hexapod kit ordered online that includes a built-in Arduino compatible board (it’s based on the Arduino 2560 Mega). The legs were redesigned to match the aesthetic that [Cory] was going for. The redesign allows for an extra pivot in the leg mechanism. The turret section was designed and built on top of the base with support for a servo to turn it (though the firmware isn’t quite there yet). After all the parts were 3d printed, the laborious process of painting began. With some delicate airbrushing and some quick stencils cut for the decals, it was complete.
When we first looked at this tank, we thought it was pretty cool. The sides are unpainted 1/2″ (12mm) plywood, so it is not flashy. The dimensions came from Google-fu-ing the heck out of the WWII Hetzer and scaling them to 1:6. What knocks our socks off is how much [Bret Tallent] made use of parts you would find in a hardware store or bicycle shop. He uses twin motors from electric bikes, and the wheels look like replacement shopping cart wheels. The best part is the treads, which are dozens of hinges fastened with pairs of bolts and nylon-insert nuts. Something is reassuring about knowing that a repair to your baby is no further than a bike ride.
We don’t know what started [Bret] on his path to sidewalk superiority, but we suspect he is cooped up like the rest of us and looking to express himself. Mini-Hetzer is not licensed by Power Wheels and never will be, so it probably won’t turn into a business anytime soon. There is a complete gallery starting with an empty plywood base, and the pictures tell the story of how this yard Jäger got to this point. There are plans to add a paintball gun and streaming video, so we’d advise that you don’t mess with the jack-o-lanterns on his block this year. Give his gallery a view and see if you don’t become inspired to cobble something clever from the hardware store too. Then, tell us about it.
Radio control is good and all, and it’s always fun to watch a little vehicle scoot about the backyard. But there’s always something to be said for feeling as though you’re really in control. First person view, or FPV, is the way to do it, and [Brian] has gone down that route with this tidy tank build.
The tank is 3D printed, from the chassis right down to the wheels. There’s even a moving “eye” up front containing the FPV camera, controlled by a servo, allowing the driver to look up and down. A 5.8 GHz transmitter is used to send the signal back to the driver’s goggles. The tracks are a snap-together design that are fully 3D printed, requiring no additional metal links or hardware. Forward propulsion is courtesy of a pair of 12 volt gear motors, driven from an L298N motor driver. An Arduino Nano is used in conjunction with Spektrum RC gear to receive signals and tell the tank where to go.
There’s almost always more than one way to get any particular job done. Suppose for instance you have a tank you fill up from a well, and you’d like to know when the time is right to refill the tank. The obvious answer is to measure the level of the tank, and there are plenty of ways to do that. However, [Liam Hanninen] has a different approach. Using a flow meter, he measures how much water leaves the tank. Assuming that you know it was once full, you can deduce how much water is left.
Using a YF-S201 flowmeter on a Raspberry Pi, the code uses Python to populate a database. The meter will need to be calibrated to get an exact volume measurement.