Year: 2022

Simple CNC Gear Production With Arduino

October 10, 2022 by 21 Comments

We’ve seen plenty of people 3D printing custom gears over the years, but [Mr Innovative] decided against an additive process for his bespoke component. He ended up using a simple CNC machine that makes use of several components that were either salvaged from a 3D printer or produced on one. Using a small saw blade, the machine cuts gear teeth into some plastic material and — presumably — could cut gears into anything the saw blade was able to slice into, especially if you added a little lubrication, cooling, and dust removal.

If you’ve built a 3D printer, you’ll see a lot of familiar parts. Stepper motors, aluminum extrusion, straight rods, bearing blocks, and rod holders are all used in the build. There’s also a lead screw and the associated components you usually see in a printer’s Z-axis. Naturally, an Arduino drives the whole affair.

The saw blade was custom-made from a washer, grinding an edge and using a 3D printed template to cut teeth in it. We might have been more inclined to use a cut-off wheel from a rotary tool, but this certainly did the trick. An LCD accepts the gear diameter and number of teeth. The stepper rotates the correct number of degrees and another stepper lowers the cutting head which is spinning with a common DC motor.

As impressive as this machine is, the fact remains that a 3D printer can produce more complex designs. For example, a herringbone pattern can help with alignment issues. It has been done many times. You can even use a resin printer, although you might prefer to stick with FDM.

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Lithium-Ion Battery Circuitry Is Simple

October 10, 2022 by 55 Comments

By now, we’ve gone through LiIon handling basics and mechanics. When it comes to designing your circuit around a LiIon battery, I believe you could benefit from a cookbook with direct suggestions, too. Here, I’d like to give you a collection of LiIon recipes that worked well for me over the years.

I will be talking about single-series (1sXp) cell configurations, for a simple reason – multiple-series configurations are not something I consider myself as having worked extensively with. The single-series configurations alone will result in a fairly extensive writeup, but for those savvy in LiIon handling, I invite you to share your tips, tricks and observations in the comment section – last time, we had a fair few interesting points brought up!

The Friendly Neighborhood Charger

There’s a whole bunch of ways to charge the cells you’ve just added to your device – a wide variety of charger ICs and other solutions are at your disposal. I’d like to focus on one specific module that I believe it’s important you know more about.

You likely have seen the blue TP4056 boards around – they’re cheap and you’re one Aliexpress order away from owning a bunch, with a dozen boards going for only a few bucks. The TP4056 is a LiIon charger IC able to top up your cells at rate of up to 1 A. Many TP4056 boards have a protection circuit built in, which means that such a board can protect your LiIon cell from the external world, too. This board itself can be treated as a module; for over half a decade now, the PCB footprint has stayed the same, to the point where you can add a TP4056 board footprint onto your own PCBs if you need LiIon charging and protection. I do that a lot – it’s way easier, and even cheaper, than soldering the TP4056 and all its support components. Here’s a KiCad footprint if you’d like to do that too.

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A Raspberry Pi Phone For The Modern Era

October 10, 2022 by 43 Comments

While it might seem like mobile phones are special devices, both in their ease of use and in their ubiquity in the modern culture, they are essentially nothing more than small form-factor computers with an extra radio and a few specific pieces of software to run. In theory, as long as you can find that software (and you pay for a service plan of some sort) you can get any computer to work as a phone. So naturally, the Raspberry Pi was turned into one.

[asherdundas], the phone’s creator, actually found a prior build based around the Raspberry Pi before starting this one. The problem was that it was built nearly a decade ago, and hadn’t been updated since. This build brings some modernization to the antiquated Pi phone, and starts with a 3D printed case. It also houses a touchscreen and a GSM antenna to connect to the cell network. With some other odds and ends, like a speaker and microphone, plus a battery and the software to tie it all together, a modern functional Raspberry Pi phone was created, with some extra details available on the project page.

The phone has the expected features — including calling, texting, and even a camera. A small WiFi USB dongle allows it to connect to the Internet too, allowing it to do all of the internet browsing a modern smartphone might want to do. The only thing that it might be pretty difficult to do is install Android apps, and although there are ways to get Android apps working in Linux, it’s not always strictly necessary to have this functionality.

3d printed fish feeder system with food basin, electronic housing with red button on top and servo attached on the side. A pile of food is coming out of the 3D printed fish feeder mechanism. In the middle of the picture is a can of goldfish pellet food. On the right is a hand interacting with a propped up cell phone, setting a time.

Sleep Easy With The Fishes Well Fed

October 10, 2022 by 3 Comments

Sometimes daily tasks, like feeding pets, can feel like a real chore. To help with alleviate the mundane aspects of daily life, [Erik Berglund] has created an automatic fish feeder, complete with 3D print files, firmware, and an Android app for complete control over scheduling and feeding.

The mechanics of the fish feeder include a screw conveyor system that pushes the food pellets fed from a food store basin. The screw conveyor is driven by a Feetech FS5106R servo which provides enough force to overcome jamming that might occur with pellets getting stuck in the conveyor system. [Erik Berglund] writes that the system can dispense about 0.9 g/s and that it’s designed for granulated food, as flakes have problems because “their low density and large surface area tend to get them stuck in the throat of the hopper” — an issue that we’ve looked into previously.

[Erik Berglund] used [coberdas]’s fish feeder as the base, upgrading it with a better servo, adding a Raspberry Pi Zero W along with software for the Pi and an Android application to control the schedule of feedings. There’s also a DS1307 real time clock module to keep precision time and a push button for “manual” feeding. If you’re looking to follow along at home, you can find the Python scripts that run on the Pi and the source code for the Android application in their respective GitHub repositories.

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An e-ink screen mounted on a small white box is flanked by four mechanical keyboard switches. A power cable is routed from the device to a power bank that is mostly out of frame.

DIY E-Reader Has Hot Swap Mechanical Keys

October 9, 2022 by 6 Comments

In the early days of e-readers, most devices had physical buttons to turn pages and otherwise navigate the device. [bwkrayb] longed for these halcyon days before touchscreen e-readers and improved on the concept by adding mechanical keyswitches.

By using an Adafruit NeoKey 1×4 as the keyboard interface, the e-reader has four hot-swappable keyboard sockets with built-in LEDs. [bwkrayb] is hoping to use these LEDs to implement a front lighting system in a future revision of the hardware.

The 3.7″ screen displays pages after running an EPUB through ebooklib and Beautiful Soup to generate files that can be used by the Waveshare drivers. Refresh time is reportedly slow, although [bwkrayb] suspects this  might be due more to the limited power of the Raspberry Pi Zero 2 more than the display itself.

If you want to see some other open e-reader projects we’ve covered, check out the EPub-Inkplate or the Open Book Project.

A 3d printed ghost next to the base of an LED tea light that has 4 LEDs poking out and the IR receiver port and micro-USB connector showing.

A Cold Light To Warm Your Heart

October 9, 2022 by 1 Comment

Halloween is coming fast and what better way to add to your Halloween ornamentation than [Wagiminator]’s cute NeoCandle tea light simulator.

[Wagiminator] has modified a 3D printed ghost along with extending [Mark Sherman]’s light simulation code to create a cute light that’s perfect for the holiday season. The NeoCandle uses an ATtiny85 chip to power four WS2812 NeoPixel jelly bean LEDs. The device has an infrared (IR) receiver to be able to control it from a remote that speaks the NEC protocol. There is a light sensor that allows the unit to dim when it detects ambient light and the whole unit is powered off of a micro-USB connection.

The ATtiny85 have limited program flash and [Wagiminator] packs in a lot of functionality in such a small package, squeezing in a bit-banging NeoPixel driver in only 18 bytes of flash that can push out a transfer rate 762 kpbs to update the LEDs. The pseudo-random number uses a Galois linear feedback shift register and comes in at 86 bytes of flash, with the IR receiver implementation code being the largest using 234 bytes of flash. The ATtiny85 itself has 8 KB of flash memory so maybe it’s possible to push [Waginminator]’s code to even more restrictive Atmel devices in the ATtiny family.

With microcontrollers and LEDs becoming so cheap and ubiquitous, making realistic flames with them is becoming accessible, as we’ve seen with previous projects on electronic candles.

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Hackaday Links: October 9, 2022

October 9, 2022 by 16 Comments

Don’t you just hate it when you walk out of the bathroom with toilet paper stuck to your shoe? That’s a little bit like what happened when the Mars helicopter Ingenuity picked up a strange bit of debris on one of its landing pads. The foreign object was spotted on the helicopter’s down-pointing navigation camera, and looks for all the world like a streamer of toilet paper flopping around in the rotor wash. The copter eventually shed the debris, which wafted down to the Martian surface with no further incident, and without any apparent damage to the aircraft. NASA hasn’t said more about what the debris isn’t — aliens — than what it is, which of course is hard to say at this point. We’re going to go out on a limb and say it’s probably something we brought there, likely a scrap of plastic waste lost during the descent and landing phase of the mission. Or, you know, it’s getting to be close to Halloween, a time when the landscape gets magically festooned with toilet paper overnight. You never know.

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