[Mark Rehorst] has been busy designing and building 3D printers, and Son of Megamax — one of his earlier builds — needed a bed heater replacement. He took the opportunity to add a Kelvin-type kinematic mount as well. The kinematic mount and base efficiently constrain the bed in a controlled way while allowing for thermal expansion, providing a stable platform that also allows for removal and repeatable re-positioning.
After a short discussion regarding the heater replacement, [Mark] explains the design and manufacture of his kinematic mount. Of particular note are the practical considerations of the design; [Mark] aimed to use square aluminum tubing as much as possible, with machining requirements that were easily done with the equipment he had available. Time is a resource after all, and design decisions that help one get something working quickly have a value all their own.
If you’re still a bit foggy on kinematic mounts and how they work, you’re not alone. Check out our coverage of this 3D-printed kinematic camera mount which should make the concept a bit clearer.
There has been a lot of activity from [Richard Horne] regarding 3D printing filaments lately; most recently he has shared two useful designs for upping one’s filament storage and monitoring game. The first is for a DIY Heated DryBox for 3D printing filament. It keeps filament dry not just by sealing it into a plastic box with some desiccant, but by incorporating a mild and economical heater intended for reptile habitats inside. Desiccant is great, but a gently heated enclosure can do wonders for driving away humidity in the right environment. The DryBox design also incorporates a handy little temperature and humidity sensor to show how well things are working.
The second design is a simple spin-off that we particularly liked: a 3D printed adapter that provides a way to conveniently mount one of the simple temperature and humidity sensors to a filament spool with a desiccant packet. This allows storing a filament spool in a clear plastic bag as usual, but provides a tidy way to monitor the conditions inside the bag at a glance. The designs for everything are on Thingiverse along with the parts for the Heated DryBox itself.
[Richard] kindly shares the magic words to search for on eBay for those seeking the build’s inexpensive key components: “15*28CM Adjustable Temperature Reptile Heating Heater Mat” and “Mini LCD Celsius Digital Thermometer Hygrometer Temperature Humidity Meter Gauge”. There are many vendors selling what are essentially the same parts with minor variations.
Since the DryBox is for dispensing filament as well as storing it, a good spool mounting system is necessary but [Richard] found that the lack of spool standardization made designing a reliable system difficult. He noted that having spool edges roll on bearings is a pretty good solution, but only if one doesn’t intend to use cardboard-sided spools, otherwise it creates troublesome cardboard fluff. In the end, [Richard] went with a fixed stand and 3D printable adapters for the spools themselves. He explains it all in the video, embedded below.
His existing unit operates on two D-type batteries which need to be replaced once they are depleted. [Vadim] wanted to implement a reversible method since he lives in a rented place. He replaced the original cells with battery adaptors and brought out the connections using two wires. He then proceeded to add two cellphone batteries with a TPS54233 regulator so as to supply the desired voltage to the gas heater. This is interesting since the module used is an official Texas Instruments EVM instead of the traditional eBay purchase.
The batteries in question are charged using modules based on the TP4056 which in turn are fed 5V from power supply modules. The DC voltage is coupled with a LM1117 to provide power to the heater from the mains and the switch over is accomplished using an SPDT relay. The enclosure is a humble box which resembles a plastic food container and is fitted with PG9 cable glands along with a fuse holder to boot. Take a look at the original post for a plethora of images and details of construction.
This an excellent example of a project that came together using available parts to solve a problem without the frills. The DIY fish feeder is another example of a project with functional design and is a great example of DIY.
What was your first car? Mine was a 1965 Triumph Herald 12/50 in conifer green, and to be frank, it was a bit of a dog.
The Triumph Herald is a small saloon car manufactured between about 1959 and 1971. If you are British your grandparents probably had one, though if you are not a Brit you may have never heard of it. Americans may be familiar with the Triumph Spitfire sports car, a derivative on a shortened version of the same platform. It was an odd car even by the standards of British cars of the 1950s and 1960s. Standard Triumph, the manufacturer, had a problem with their pressing plant being owned by a rival, so had to design a car that used pressings of a smaller size that they could do in-house. Thus the Herald was one of the last British mass-produced cars to have a separate chassis, at a time when all other manufacturers had produced moncoques for years.
My 12/50 was the sporty model, it had the high-lift cam from the Spitfire and a full-length Britax sunroof. It was this sunroof that was its downfall, when I had it around a quarter century of rainwater had leaked in and rotted its rear bodywork. This combined with the engine being spectacularly tired and the Solex carburetor having a penchant for flooding the engine with petrol made it more of a pretty thing to look at than a useful piece of transport. But I loved it, tended it, and when it finally died irreparably I broke it for parts. Since then I’ve had four other Heralds of various different varieties, and the current one, a 1960 Herald 948, I’ve owned since the early 1990s. A piece of advice: never buy version 0 of a car.
[Ken Rumer] bought a new house. It came with a troublingly complex pool system. It had solar heating. It had gas heating. Electricity was involved somehow. It had timers and gadgets. Sand could be fed into one end and clean water came out the other. There was even a spa thrown into the mix.
Needless to say, within the first few months of owning their very own chemical plant they ran into some near meltdowns. They managed to heat the pool with 250 dollars of gas in a day. They managed to drain the spa entirely into the pool, but thankfully never managed the reverse. [Ken] knew something had to change. It didn’t hurt that it seemed like a fun challenge.
The first step was to tear out as much of the old control system as could be spared. An old synchronous motor timer’s chlorine rusted guts were ripped out. The solar controler was next to be sent to its final resting place. The manual valves were all replaced with fancy new ones.
Rather than risk his fallible human state draining the pool into the downstairs toilet, he’d add a robot’s cold logical gatekeeping in order to protect house and home. It was a simple matter of involving the usual suspects. Raspberry Pi and Arduino Man collaborated on the controls. Import relay boards danced to their commands. A small suite of sensors lent their aid.
Now as the soon-to-be autumn sun sets, the pool begins to cool and the spa begins to heat automatically. The children are put to bed, tired from a fun day at the pool, and [Ken] gets to lounge in his spa; watching the distant twinkling of lights on his backyard industrial complex.
Most circuit boards any maker could need for their projects can be acquired online at modest cost, but what if you need something specific? [Giorgos Lazaridis] of pcbheaven.com has designed his own etching bath complete with a heater and agitator to sped up the process of creating your own custom circuit boards.
[Lazaridis] started by building a circuit to control — in a display of resourcefulness — a fish tank heater he would later modify. The circuit uses a PIC 16F526 microcontroller and two thermristors to keep the temperature of the etching bath between 38 and 41 degrees Celsius. The fish tank heater was gingerly pried from its glass housing, and its bimetallic strip thermostat removed and replaced with a wire to prevent it shutting off at its default 32 degrees. All of it is mounted on a small portable stand and once heated up, can etch a board in less than 10 minutes.
Ahh, sweet scope creep! Usually it’s the death of a nice, simple little hack. But once in a hundred times, a small hack doesn’t get buried under the extra features, but instead absorbs them in stride and blossoms into a beautiful system. [rockfishon]’s Arduino-powered wood stove controller is one of these beautiful exceptions. (OK, we’d admit that it could use a fancier faceplate.)
He started off simply enough, wanting to connect a thermocouple to an Arduino, read out the value, and issue an alarm when the temperature got too high. But who could stop there? Just one air-baffle servo away from a closed-loop heating control system? So [rockfishon] added a display and a few more buttons and has a system that will keep his wood-burning stove running at exactly the right temperature, even overnight when nobody’s around to tend it. As a bonus, everything is logged for later analysis.