Reed Organ MIDI Conversion Tickles All 88 Keys

What did you do in high school? Chances are it wasn’t anywhere near as cool as turning a reed organ into a MIDI device. And even if you managed to pull something like that off, did you do it by mechanically controlling all 88 keys? Didn’t think so.

A reed organ is a keyboard instrument that channels moving air over sets of tuned brass reeds to produce notes. Most are fairly complex affairs with multiple keyboards and extra controls, but the one that [Willem Hillier] scored for free looks almost the same as a piano. Even with the free instrument [Willem] is about $500 into this project. Almost half of the budget went to the solenoids and driver MOSFETs — there’s a solenoid for each key, after all. And each one required minor surgery to reduce the clicking and clacking sounds that don’t exactly contribute to the musical experience. [Willem] designed custom driver boards for the MOSFETs with 16 channels per board, and added in a couple of power supplies to feed all those hungry solenoids and the three Arduinos needed to run the show. The video below shows the organ being stress-tested with the peppy “Flight of the Bumblebee”; there’s nothing wrong with a little showing off.

[Willem]’s build adds yet another instrument to the MIDI fold. We’ve covered plenty before, from accordions to harmonicas and even a really annoying siren.

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Super simple controller for Motorcycle LED lights

For automobiles, especially motorcycles, auxiliary lighting that augments the headlights can be quite useful, particularly when you need to drive/ride through foggy conditions and poorly lit or unlit roads and dirt tracks. Most primary lighting on vehicles still relies on tungsten filament lamps which have very poor efficiency. The availability of cheap, high-efficiency LED modules helps add additional lighting to the vehicle without adding a lot of burden on the electrical supply. If you want to add brightness control, you need to either buy a dimmer module, or roll your own. [PatH] from WhiskeyTangoHotel choose the latter route, and built a super simple LED controller for his KLR650 bike.

He chose a commonly available 18 W light bar module containing six 3 W LEDs. He then decided to build a microcontroller based dimmer to offer 33%, 50% and 100% intensities. And since more code wasn’t going to cost him anything extra, he added breathing and strobe modes. The hardware is as barebones as possible, consisting of an Arduino Nano, linear regulator, power MOSFET and control switch, with a few discretes thrown in. The handlebar mounted control switch is a generic motorcycle accessory that has two push buttons (horn, headlight) and a slide switch (turn indicators). One cycles through the various brightness modes on the pushbutton, while the slide switch activates the Strobe function. A status indicator LED is wired up to the Nano and installed on the handlebar control switch. It provides coded flashes to indicate the selected mode.

It’s a pity that the “breathing” effect is covered under a patent, at least for the next couple of years, so be careful if you plan to use that mode while on the road. And the Strobe mode — please don’t use it — like, Ever. It’s possible to induce a seizure which won’t be nice for everyone involved. Unless you are in a dire emergency and need to attract someone’s attention for help.

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Educational Robot for Under $100

While schools have been using robots to educate students in the art of science and engineering for decades now, not every school or teacher can afford to put one of these robots in the hands of their students. For that reason, it’s important to not only improve the robots themselves, but to help drive the costs down to make them more accessible. The CodiBot does this well, and comes in with a price tag well under $100.

The robot itself comes pre-assembled, and while it might seem like students would miss out on actually building the robot, the goal of the robot is to teach coding skills primarily. Some things do need to be connected though, such as the Arduino and other wires, but from there its easy to program the robot to do any number of tasks such as obstacle avoidance and maze navigation. The robot can be programmed using drag-and-drop block programming (similar to Scratch) but can also be programmed the same way any other Arduino can be.

With such a high feature count and low price tag, this might be the key to getting more students exposed to programming in a more exciting and accessible way than is currently available. Of course, if you have a little bit more cash lying around your school, there are some other options available to you as well.

Jenkins Given an Industrial Stack Light for Build Reporting

When working on software development in a team environment, it’s important to know the status of your build at all times. Jenkins can display build automation info on a screen but where’s the fun in that? A popular office project is to build some kind of visual display of a project’s status, and [dkt01] has done just that with this stack light build monitor.

In this day and age of online shopping, random bits of industrial hardware are just an eBay away, so it’s easy to find some cool lamps or indicators for any project. [dkt01] sourced a standard 24V stack light off the shelf. With its green, red, and yellow indicators, its perfect for showing the current status of their build server.

The project uses an Arduino Pro Micro combined with an ENC28J60 Ethernet adapter. We used to see that chip all the time but in 2017 it’s somewhat of a classic setup with the great unwashed masses largely migrating to the ESP8266. However, for the purposes of this project, it was perfect for connecting to the wired office network (after all, you want to know the status of your build and not of your WiFi). [dkt01] even managed to get a web configuration to work despite the relatively meager resources of the ATmega32u4.

The build is cleanly executed, with the microcontroller and Ethernet hardware tucked into a 3D printed base for the stack light’s enclosure. It’s far more likely to become a permanent office fixture if it’s a tidy build without wires hanging out everywhere so a custom PCB ties everything together neatly. In another nice touch, the stack lights flash on initialization to indicate if the DHCP lease was successful, which makes troubleshooting easier. There’s an overview of all different light combinations and meanings in the video after the break.

Overall it’s a solid build with some off-the-shelf components that serves a genuine purpose. For a similar project built on a smaller scale, check out the Indictron. For something bigger, show us how you’ve learned to output your server status on the city’s traffic lights. Ask first, though.
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Hackaday Prize Entry: Vibhear

Hearing impairment, either partial or total, is a serious problem afflicting a large number of people. Almost 5% of the global population has some form of hearing disorder. For those affected by this disability from birth, it further impacts the development of language and speech abilities. In recent years, cochlear implants are increasingly being used to address this problem. These implants consist of two parts – the receiver and electrode array are implanted under the skin near the ear (with the electrode array terminating inside the Cochlea), while the microphone, electronics, transmitter and power source are attached on the outside. Often, the external unit has to be removed – for example, when the person needs to sleep. This is particularly so in the case of young children. The external unit is fairly large compared to their head and causes discomfort during sleep. And parents are worried that the expensive device could get damaged when the child is sleeping. This leads to the alarming situation where the child is asleep and has no audio sensory inputs being received from the surroundings. Not only can they not hear morning alarms, but also cannot react when there is an emergency situation such as a smoke alarm going off.

[Srdjan Pavlovic] came across this problem first hand when he visited his friend and learned about their six-year-old son with hearing loss since birth. The parents said their child will not be disturbed by loud noises at night since the external unit of his cochlear implant is removed each night. [Srdjan] then started work on building the Vibhear – an assistive hearing device to be used when the main hearing aid is removed or not working. It is a low-cost arm-band that provides a vibratory signal in response to high ambient noises.

The main components are a microphone, amplifier, microcontroller and vibration motor powered by a LiPo battery through a boost converter/charger. An RTC module allows setting up daily wake up alarms. It’s currently prototyped around the Arduino, but the next iteration will use a specialized DSP which can be programmed to perform signal processing operations on input sound. This will allow identification of specific sounds such as car horns, barking dogs, smoke alarms or emergency sirens.

[Srdjan] is in the process of choosing components for his next iteration, so if you have any recommendations to help him choose the microcontroller, power supply controller or other parts, do let him know via comments below.

Impressive Drawing Machine For One Made So Simply

Not all of us have CNC machines, laser cutters and 3D printers, and I’ll bet most of us didn’t start out that well equipped. The low-cost drawing machine that [jegatheesan] made for his daughter reminds us that you can prototype, and then make a functioning mechanical Da Vinci with very basic materials and mostly hand tools. He also wrote his own drawing software, with an interface that has its own simplicity.

There really are a lot of things to like about [jegatheesan]’s project. He first works out the math himself by doing something the likes of which we’ve all enjoyed, digging out the old school trigonometry and algebra books for a refresher. Then he got started on his prototype, made using a cardboard tube for the main support and straws and safety pins for the drawing arms. He already had a motor shield for his Arduino but it supported only 2 servos, so he made his own 3-servo shield. In the end, the prototype told him he had to redo some calculations, allowing him to move on to the final machine.

One thing we can say about the final machine is that hot glue must truly be the maker’s connect-all — you won’t find many screws here. Even the servos are held in place with copious quantities of glue. And the mechanism for lifting the pen is also quite clever. The whole thing is mounted on two vertical guide rods, so that it can easily slide up and down. To get it to actually move up and down, he glued a toy car wheel off-center on a servo arm. When the servo turns, the off-center wheel acts like a cam, pushing down on the wooden base to either lift the machine up or lower it down, depending on where the wheel is in its rotation.

See his hackaday.io page for the full step-by-step development process. But first check out the videos below to see how impressive such a simply made machine is in action.

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A BluePill for Arduino Dependence

Arduinos are helpful but some applications require more than what Arduinos can provide. However, it’s not always easy to make the switch from a developed ecosystem into the abyss that is hardware engineering. [Vadim] noticed this, which prompted him to write a guide to shepherd people on their quest for an Arduino-free environment, one BluePill at a time.

With an extended metaphor comparing Arduino use and physical addiction, [Vadim’s] writing is a joy to read. He chose to focus on the BluePill (aka the next Arduino Killer™) which is a $1.75 ARM board with the form factor of an Arduino Nano. After describing where to get the board and it’s an accompanying programmer, [Vadim] introduces PlatformIO, an alternative to the Arduino IDE. But wait! Before the Arduino die-hards leave, take note that PlatformIO can use all of the “Arduino Language,” so your digitalWrites and analogReads are safe (for now). Like any getting started guide, [Vadim] includes the obligatory blinking an LED program. And, in the end, [Vadim] sets his readers up to be comfortable in the middle ground between Arduino Land and the Wild West.

The debate for/against Arduino has been simmering for quite some time, but most agree that Arduino is a good place to start: it’s simpler and easier than jumping head first. However, at some point, many want to remove their “crippling Arduino dependency” (in the words of [Vadim]) and move on to bigger and better things. If you’re at this point, or still cling to your Uno, swing on over and give Vadim’s post a read. If you’re already in the trenches, head on over and read our posts about the BluePill and PlatformIO which are great complements for [Vadim’s].