A Smarter Solar Water Heater

Installing solar power at a home is a great way to reduce electricity bills, especially as the cost of solar panels and their associated electronics continue to plummet. Not every utility allows selling solar back to the grid, though, so if you’re like [Rogan] who lives in South Africa you’ll need to come up with some clever tricks to use the solar energy each day while it’s available to keep from wasting any. He’s devised this system for his water heater that takes care of some of this excess incoming energy.

A normal water heater, at least one based on electric resistive heaters, attempts to maintain a small range of temperatures within the insulated tank. If the temperature drops due to use or loss to the environment, the heaters turn on to bring the temperature back up. This automation system does essentially the same thing, but allows a much wider range of temperatures depending on the time of day. Essentially, it allows the water heater to get much hotter during times when solar energy is available, and lets it drop to lower values before running the heater on utility electricity during times when it isn’t. Using a combination ESP32 and ATtiny to both control the heater and report its temperature, all that’s left is to program Home Assistant to get the new system to interact with the solar system’s battery charge state and available incoming solar energy.

While it’s an elegantly simple system that also affords ample hot water for morning showers, large efficiency gains like this can be low-hanging fruit to even more home energy savings than solar alone provides on paper. Effectively the water heater becomes another type of battery in [Rogan]’s home, capable of storing energy at least for the day in the form of hot water. There are a few other ways of storing excess renewable energy as well, although they might require more resources than are typically available at home.

Autofeeding CNC Lathe Cranks Out Parts All By Itself

The trouble with building a business around selling low-margin widgets is that you have to find a way to make a lot of them to make it worth your while. And if the widget in question is labor-intensive to make, you’ve got to find ways to reduce your inputs. That sounds like a job for industrial automation, a solution that’s often out of reach of small shops, for all the obvious reasons. Not if you’re clever about things, though, as this fully automated CNC lathe work cell shows.

This build comes to us from the woodshop of [Maher Lagha], where he’s making wooden honey dippers. Wooden dowel blanks are dispensed from an infeed rack and chucked between centers on the headstock and pneumatic tailstock. A two-axis stage in front of the workpiece moves a tool against the spinning stock, carving out the honey dipper in just a few minutes. When the lathe work is done, the spindle stops, the tailstock pulls the honey dipper back off the headstock, and a pneumatic piston unceremoniously whacks the almost-finished part — it looks like it still needs a little manual post-processing — into a bin. Lather, rinse, repeat, profit.

[Maher] doesn’t provide many details, but just looking at the work cell shows a veritable feast of industrial automation equipment. The spindle and tailstock of the lathe sit on a bed made from a massive slab of aluminum extrusion, and the X- and Y-axes use linear rails and ballscrews. And mindful of the effects of wood chips on delicate mechanisms, [Maher] did a good job of containing the mess with a host of acrylic guards.

As we said when we saw [Maher]’s wooden coaster work cell a while back, the wood widget business must be pretty good to justify automation like this. What’s nice with both these rigs is that they look like they could be quickly reprogrammed and retooled to create other products. Pretty impressive.

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CNC Soldering Bot Handles Your Headers

Soldering pin headers by hand is a tedious task, especially when your project has a huge number of them. [iforce2d] has a large number of boards with a lot of headers, and has created a rather special CNC machine to to do the job. It’s a soldering robot, controlled by LinuxCNC and you can see it below the break.

Superficially it resembles a 3D printer made in aluminium, with an X-Y movable table and a Z-direction represented by a soldering iron and solder feeder on an arm. The solder feeder uses a Bowden tube, with a 3D-printer extruder motor pushing the solder wire down a PTFE tube and finally into a fine aluminium tube from which it’s fed to the iron tip.

Though he’s done a beautiful job of it, creating the machine is not all that’s required, because the tool path requires more attention than simply moving the iron to each pin and supplying some solder. There’s a need to consider the effect of that heat, how much each pad needs, and how much neighbouring pads contribute.

We’ve had repetitive soldering tasks just like this one though not on this scale, so we can understand the tedium this machine will relieve. We can’t however help being reminded of XKCD 1319.

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You’ve Got Mail: Automatic For The People

When we last left the post office, I told you all about various kinds of machinery the USPS uses to move mail around. Today I’m going to tell you about the time they thought they could automate nearly every function inside the standard post office — and no, it wasn’t anytime recently.

By 1953, the post office badly needed modernization. When Postmaster General Arthur Summerfield was appointed that year, he found the system essentially in shambles. Throughout the 1930s and 40s, the USPS had done absolutely no spending beyond the necessary, with little to no investment in the future. But Summerfield was an ideas man, and he had the notion to build a totally automated post office. One of them would be located in Providence, Rhode Island and be known as Project Turnkey — as in a turnkey operation. The other would be located in Oakland, California, and serve as a gateway to the Pacific.

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Heat Pump Control That Works

Heat pumps are taking the world by storm, and for good reason. Not only are they many times more efficient than electric heaters, but they can also be used to provide cooling in the summer. Efficiency aside, though, they’re not perfectly designed devices, largely with respect to their climate control abilities especially for split-unit setups. Many of them don’t have remotely located thermostats to monitor temperature in an area, and rely on crude infrared remote controls as the only user interface. Looking to make some improvements to this setup, [Danilo] built a setup more reminiscent of a central HVAC system to control his.

Based on an ESP32 from Adafruit with an integrated TFT display, the device is placed away from the heat pump to more accurately measure room temperature. A humidity sensor is also included, as well as an ambient light sensor to automatically reduce the brightness of the display at night. A large wheel makes it quick and easy to adjust the temperature settings up or down. Armed with an infrared emitter, the device is capable of sending commands to the heat pump to more accurately control the climate of the room than the built-in controls are able to do. It’s also capable of logging data and integrating with various home automation systems.

While the device is optimized for the Mitsubishi heat pumps that [Danilo] has, only a few lines of code need to be changed to get this to work with other brands. This is a welcome improvement for those frustrated with the inaccurate climate controls of their heat pumps, and since it integrates seamlessly into home automation systems could also function in tandem with other backup heat sources, used in cold climates when it’s too cold outside to efficiently run the heat pump. And, if you don’t have a heat pump yet, you can always try and build your own.

Automation For The NES

Old hardware might not be anywhere close to as powerful as modern technology, but it does have a few perks. Aesthetics can of course drive the popularity of things like retro gaming systems, but the ease of understanding the underpinnings of their inner workings is also critical. The Nintendo Entertainment System, now nearly four decades old, is a relatively simple machine by modern standards and this lends the system to plenty of modifications, like this controller that allows the system to be somewhat automated.

The original NES controller used a fairly simple shift register to send button presses to the system. The system outputted a latch signal to the controller, the shift register would take as input the current state of the buttons, and then would send them one-by-one to the system at a rate of around 1000 times per second. These signals can be sent without a controller easily enough, too. This build uses a CD4021 shift register, which is the same as the original controller, but instead of reading button states it accepts its inputs from a separate computer via a latching circuit. In this case, the separate computer is a custom design that came about through adapting cassette storage for a 6502-based computer, but it could come from anything else just as easily.

With this system in place, it’s possible to automate gameplay to some extent. Since the system can’t get feedback about the game in its current state, it requires some precise timing to get it to play the game well, and a lot of tuning needs to go into it. This isn’t just a one-off, either. Similar methods are how we get tool-assisted speedruns of games and although these are often done in emulators instead of on real hardware, they can result in some interesting exploits.

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Automated Drone Takes Care Of Weeds

Commercial industrial agriculture is responsible for providing food to the world’s population at an incredibly low cost, especially when compared to most of human history when most or a majority of people would have been involved in agriculture. Now it’s a tiny fraction of humans that need to grow food, while the rest can spend their time in cities and towns largely divorced from needing to produce their own food to survive. But industrial agriculture isn’t without its downsides. Providing inexpensive food to the masses often involves farming practices that are damaging to the environment, whether that’s spreading huge amounts of synthetic, non-renewable fertilizers or blanket spraying crops with pesticides and herbicides. [NathanBuildsDIY] is tackling the latter problem, using an automated drone system to systemically target weeds to reduce his herbicide use.

The specific issue that [NathanBuildsDIY] is faced with is an invasive blackberry that is taking over one of his fields. To take care of this issue, he set up a drone with a camera and image recognition software which can autonomously fly over the field thanks to Ardupilot and a LiDAR system, differentiate the blackberry weeds from other non-harmful plants, and give them a spray of herbicide. Since drones can’t fly indefinitely, he’s also build an automated landing pad complete with a battery swap and recharge station, which allows the drone to fly essentially until it is turned off and uses a minimum of herbicide in the process.

The entire setup, including drone and landing pad, was purchased for less than $2000 and largely open-source, which makes it accessible for even small-scale farmers. A depressing trend in farming is that the tools to make the work profitable are often only attainable for the largest, most corporate of farms. But a system like this is much more feasible for those working on a smaller scale and the automation easily frees up time that the farmer can use for other work. There are other ways of automating farm work besides using drones, though. Take a look at this open-source robotics platform that drives its way around the farm instead of flying.

Thanks to [PuceBaboon] for the tip!

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