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We often like to say that if something is worth doing, then it’s worth overdoing. This automatic cat feeder built by [krizzli] is a perfect example of the principle. It packs in far more sensors and functions than its simple and sleek outward appearance might suggest, to the point that we think this build might just set the standard for future projects.

The defining feature of the project is a load cell located under the bowl, which allows the device to accurately measure out how much feed is being dispensed by weight. This allows the feeder to do things such as detect jams or send an alert once it runs out of food, as well as easily adjust how much is dispensed according to the animal’s dietary needs. To prevent any curious paws from getting into the machine while it’s doling out the food, the lid will automatically open and close during the filling process, complete with optical sensors to confirm that it moved as expected.

All of the major components of the feeder were printed out on a Prusa i3 MK3S, and [krizzli] says that the feed hopper can be scaled vertically if necessary. Though at the current size, it’s already packing around a week’s worth of food. Of course, this does depend on the particular feline you’re dealing with.

In terms of electronics, the feeder’s primary control comes from an ESP8266 (specifically, the Wemos D1 Mini), though [krizzli] also has a Arduino Pro Mini onboard so there’s a few more GPIO pins to play with. The food is dispensed with a NEMA 17, and a 28-BYJ48 stepper is in charge of moving the lid. A small OLED on the side of the feeder gives some basic information like the time until the next feeding and the dispensed weight, but there’s also a simple API that lets you talk to the device over the network. Being online also means the feeder can pull the time from NTP, so kitty’s mealtime will always be on the dot.

Over the years we’ve seen an incredible array of automatic cat feeders, some of which featuring the sort of in-depth metrics possible when you’ve got on onboard scale. But we can’t help but be impressed with how normal this build looks. If nothing else, of all the feeders we’ve seen, this one is probably the most likely to get cloned and sold commercially. They say it’s the most sincere form of flattery.

Do you need a small weight scale? You can of course buy one, or you could instead make your own 3D-printed device with a load cell and an Arduino, as shown in the below video by MN Maker.

In his setup, the load cell first sends readings to an HX711 breakout board, which converts this analog signal into a digital output that the Nano can easily interpret. The output is displayed on a 0.96” 128×64 OLED, with a button on the back to switch power on and off, and another to tare the scale to zero. 

Code for the project is available here, while print files can be found on Thingiverse.

When the average person looks at a bed, they think about sleeping. Because that’s what beds are for. You cover them with soft, warm cloths and fluffy pillows and you sleep on them. [Peter] is not your average person. He’s a maker. And when he looks at a bed, he thinks about giving it the ability to track his weight.

The IKEA bed has four Chinese-made TS-606 load cells under each foot with custom aluminum enclosures. Each one goes to an HX711 analog-to-digital converter, which offers a 24 bit resolution. These feed an Arduino Nano which in turns connects to a Raspberry Pi via USB to UART bridge. Connecting to the Pi allows [Peter] to get the data onto his home network, where he plots the data to gnuplot.

This smart bed doesn’t just track [Peter’s] weight. It can also track the weight of other people in the house, including his pets. Be sure to check his GitHub for full source code.


Filed under: Arduino Hacks

[Paul] participated in a hackathon at work and created a hack to help solve what was ultimately a people problem. A soda fridge at work wasn’t getting refilled when empty. Instead of trying to make people less lazy, [Paul] went with making the fridge more needy.

The first thing [Paul] did was make a soda fridge refill sensor from a scale. As the fridge got emptier, it got lighter. The scale senses that and can decide it’s time for a refill. The only part missing was how to read the output from the scale. To do that, he took an unusual approach.

Soda Fridge on Hacked Scale
Soda fridge on an analog scale with color sensor reading the dial

The soda fridge sits on an analog scale with a dial. [Paul] saw there was no need to measure the exact weight of the fridge, only to detect a refill threshold. He came up with a simple hack: colored paper attached to the scale’s dial and an Arduino with an OSEPP COLOR‑01 color sensor pointed at the paper. The dial moves in response to the fridge’s changing weight, and the color sensor reads the color of the paper as it moves under the sensor. With a little bit of trial-and-error calibration and some barely modified sample code for the sensor, it was possible to reliably detect when the fridge required refilling. With the sensor done, it was time to use it to solve the lazy people problem.

In a way, the root problem wasn’t that people couldn’t be bothered to check if the fridge needed a refill – it was that the right people weren’t finding out at the right times. This resulted in spotty refilling as well as soda not being ordered when needed. This hack means that the fridge can now actively announce its state, which now allows things like notifying people via email that it is their turn to refill and re-order. It turns out that a fridge that can tell people what it needs has a much better chance of being serviced, compared to a one that has to wait for people to check up on it.

We’ve seen people interface directly to the load sensors in weight scales before, but this hack took a completely different approach.

Thanks to [Paul] for sharing.


Filed under: Arduino Hacks

Beehive connected to internet.Learn how to pull realtime sensor data from a beehive to monitor its weight, temperature, and humidity over the internet.

Read more on MAKE

The post The Internet of Bees: Adding Sensors to Monitor Hive Health appeared first on Make: DIY Projects, How-Tos, Electronics, Crafts and Ideas for Makers.

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Adding a display to a USB digital scale

arduino, arduino hacks, HD44780, scale Commenti disabilitati su Adding a display to a USB digital scale 

arduino_scale

[Oleg] found himself in possession of a Stamps.com Model 510 5lb digital scale.  It’s a great scale, but only works as a USB HID device. In other words, it’s a digital scale without a digital display. He decided he wanted it to be more standalone, so he added a Toshiba HD44780 (compatible) display. An Arduino UNO and USB Host shield were used to make it happen. His sketch simply polls the scale and outputs the weight on the display.

In this case, he used the USB Host Shield from Circuits at Home, but a brief look shows they use the same MAX3421 controller chip as Sparkfun and other versions of the board. You might also be able to pull off the same functionality with an AVR running V-USB, though admittedly it wouldn’t be so easy.

We haven’t found a great way to add USB host mode to projects other than shields like the one [Oleg] used. If you know of a better way, share your ideas in the comments.

Of course, if this isn’t hardcore enough for you, forget using a consumer scale – make your own from scratch!


Filed under: Arduino Hacks


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