Automated System Keeps Camper Van Air Fresh And Warm

Air quality has become a hot topic in recent years. [Ryan Stout] was interested in improving it in his camper van, and set about doing something about it. His solution was an automated system that provided cleaner air and better comfort to boot.

The concept was simple. [Ryan]’s system is based on an Arduino clone, and uses a SparkFun SCD40 as a CO2 sensor, and an MCP9808 for temperature. When the system detects excess carbon dioxide levels, it opens the MaxxAir fan in the camper by triggering it with an infrared signal. Similarly, when it detects excessively low temperatures inside the van, it kicks on a diesel furnace for heating. In a neat addition, to avoid the fan sucking in exhaust fumes, it also closes the fan in order to avoid exhaust fumes entering the camper unnecessarily. All the hardware was then  wrapped up in a simple 3D printed enclosure.

With this setup, [Ryan] has managed to cut the buildup of CO2 in his camper at night, and he credits this with reducing morning headaches when he’s out in the camper. We’d call that a win, to say nothing of the additional comfort created by the automatically-controlled heater! If you’re interested in something similar for your home HVAC system, we’ve got you covered.

More Ideas For Setting Up An Electronics Workbench

Setting up an electronics work area is a highly personal and situational affair, with many interesting problems to be solved, and for many of us, significant budget constraints. The requirements for electronics development vary wildly depending upon the sort of work to be undertaken, but there is core equipment that many of us would consider a bare minimum for usability. [Badar Jahangir Kayani] is at the start of his career as an electrical engineer, and has documented the kitting out of his personal work areas for others to learn from.

A place for everything, everything in its place

As we already touched upon, the cost is often the main driving factor determining what we end up with, and this cost-vs-performance/quality tradeoff is what makes some of us fret over a buying decision. Buying secondhand off eBay is an option, but a lack of warranty and the unknowable condition are not great selling points.

[Badar] has a good grasp of the basic concepts of usability, such as keeping the most frequently used tools, instruments, and components out in the open. Less frequently used stuff is stored in drawers, bins, and compartment boxes. Buying the same storage systems keeps things as consistent as much as possible since it makes storing them easier. We were particularly interested in the use of the cloud-based database solution, Airtable used to create a parts database for minimal outlay.

Oooh! Cable tray action

There is also a lot of detail about how to walk that cost/quality/performance tightrope and get the best-valued gear currently on the market. Some notable examples are the UNI-T UT61E Digital Multimeter for general test use, the Controleo3 reflow controller for SMT assembly, and the Omnifixo OF-M4 magnetic fixament kit for that fiddly wiring part. [Badar] also recommends the FumeClear Solder Fume Extractor, although they lament that particular bit of kit is still under evaluation.

Obviously, we’ve talked about work areas a lot on these pages, like this time. For those with more space, this flippin’ awesome bench will be of interest, and if space is tight (or travel is a regular thing) might we suggest this 3D printed DIN-rail mounting cube as a starting point?

Transistors That Grow On Trees

Modern technology is riddled with innovations that were initially inspired by the natural world. Velcro, bullet trains, airplanes, solar panels, and many other technologies took inspiration from nature to become what they are today. While some of these examples might seem like obvious places to look, scientists are peering into more unconventional locations for this transistor design which is both inspired by and made out of wood.

The first obvious hurdle to overcome with any electronics made out of wood is that wood isn’t particularly conductive, but then again a block of silicon needs some work before it reliably conducts electricity too. First, the lignin is removed from the wood by dissolving it in acetate, leaving behind mostly the cellulose structure. Then a conductive polymer is added to create a lattice structure of sorts using the wood cellulose as the structure. Within this structure, transistors can be constructed that function mostly the same as a conventional transistor might.

It might seem counterintuitive to use wood to build electronics like transistors, but this method might offer a number of advantages including sustainability, lower cost, recyclability, and physical flexibility. Wood can be worked in a number of ways once the lignin is removed, most notably when making paper, but removing the lignin can also make the wood relatively transparent as well which has a number of other potential uses.

Thanks to [Adrian] for the tip!

MOSFET Heater Is Its Own Thermostat

While we might all be quick to grab a microcontroller and an appropriate sensor to solve some problem, gather data about a system, or control another piece of technology, there are some downsides with this method. Software has a lot of failure modes, and relying on it without any backups or redundancy can lead to problems. Often, a much more reliable way to solve a simple problem is with hardware. This heating circuit, for example, uses a MOSFET as a heating element and as its own temperature control.

The function of the circuit relies on a parasitic diode formed within the transistor itself, inherent in its construction. This diode is found in most power MOSFETs and conducts from the source to the drain. The key is that it conducts at a rate proportional to its temperature, so if the circuit is fed with AC, during the negative half of the voltage cycle this diode can be probed and used as a thermostat. In this build, it is controlled by a set of resistors attached to a voltage regulator, which turn the heater on if it hasn’t reached its threshold temperature yet.

In theory, these resistors could be replaced with potentiometers to allow for adjustable heat for certain applications, with plastic cutting and welding, temperature control for small biological systems, or heating other circuits as target applications for this type of analog circuitry. For more analog circuit design inspiration, though, you’ll want to take a look at some classic pieces of electronics literature.

Sixteen wires of various colors are attached in pairs to record the electrical activity of split gill fungi (Schizophyllum commune) on a mossy, wooden stick. photo by Irina Petrova Adamatzky

Unconventional Computing Laboratory Grows Its Own Electronics

While some might say we’re living in a cyberpunk future already, one technology that’s conspicuously absent is wetware. The Unconventional Computing Laboratory is working to change that.

Previous work with slime molds has shown useful for spatial and network optimization, but mycelial networks add the feature of electrical spikes similar to those found in neurons, opening up the possibility of digital computing applications. While the work is still in its early stages, the researchers have already shown how to create logic gates with these fantastic fungi.

Long-term, lead researcher [Andrew Adamatzky] says, “We can say I’m planning to make a brain from mushrooms.” That goal is quite awhile away, but using wetware to build low power, self-repairing fungi devices of lower complexity seems like it might not be too far away. We think this might be applicable to environmental sensing applications since biological systems are likely to be sensitive to many of the same contaminants we humans care about.

We’ve seen a other efforts in myceliotronics, including biodegradable PCB substrates and attempts to send sensor signals through a mycelial network.

Via Tom’s Hardware.

A notated illustration showing how a mycelial network may be functionalized as a PCB substrate. The process starts with Cu vapor deposition onto the network followed by Au either by more vapor deposition or electrodeposition. Traces are then cut via laser ablation.

MycelioTronics: Biodegradable Electronics Substrates From Fungi

E-waste is one of the main unfortunate consequences of the widespread adoption of electronic devices, and there are various efforts to stem the flow of this pernicious trash. One new approach from researchers at the Johannes Kepler University in Austria is to replace the substrate in electronics with a material made from mycelium skins.

Maintaining performance of ICs and other electronic components in a device while making them biodegradable or recyclable has proved difficult so far. The substrate is the second largest contributor (~37% by weight) to the e-waste equation, so replacing it with a more biodegradable solution would still be a major step toward a circular economy.

To functionalize the mycelial network as a PCB substrate, the network is subjected to Physical Vapor Deposition of copper followed by deposition of gold either by more PVD or electrodeposition. Traces are then cut via laser ablation. The resulting substrate is flexible and can withstand over 2000 bending cycles, which may prove useful in flexible electronics applications.

If you’re looking for more fun with fungi, check out these mycelia bricks, this fungus sound absorber, or this mycellium-inspired mesh network.

A Great Resource For The Would-Be Pinball Machine Builder

Those of us beyond a certain age will very likely have some fond memories of many an hour spent and pocket money devoured feeding the local arcade pinball machine. At one time they seemed to be pretty much everywhere, but sadly, these days they seem to have largely fallen out of favour and are becoming more of speciality to be specifically sought out. Apart from a few random ones turning up — there’s a fun Frankenstein-themed machine in the Mary Shelley Museum in Bath, England — a trip to a local amusement arcade is often pretty disappointing, with modern arcade machines just not quite scratching that itch anymore, if you ask us. So what’s an old-school hacker to do, but learn how to build a machine from scratch, just the way we want it? A great resource for this is the excellent Pinball Makers site, which shows quite a few different platforms to build upon and a whole ton of resources and guides to help you along the way.

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