Old Midi Instruments Don’t Like Modern Midi. What’s To Be Done?

In theory, MIDI is an electrical and protocol standard that allows any such equipped instrument or computer to talk to any other. But as the wonderfully named [Knob Monster] will tell you, when the computer is new, and the instrument is old, it ain’t that simple.

They specialise in using the Web MIDI interface to allow browser control of an instrument. This might typically be done with a USB to MIDI interface, but in this lies a problem. The 8-bit microprocessor on a 1983 synth has problems keeping up with the rapid-fire data that spews relentlessly from the supercomputer-grade machine controlling it, and bad things happen as a result.

Expensive MIDI interfaces have a buffer built in, but a better solution lies in the Web MIDI code itself. They detail how to use the Web MIDI API’s built-in packet scheduler to slow things down a little and let your Yamaha DX7 chill a bit.

Meanwhile, if you need a USB to MIDI interface, we’ve covered one in the past.

Leaky Player Piano Gets MIDI Upgrade In YouTube Restomod

The word “restomod” is a bit nebulous, but it’s normally used in the automotive world to describe taking an old car and making it better-than-new with all the technological improvements the original builders would have used, had they been available. We think the word applies to [Alnwlsn]’s MIDI-actuated player piano, because what are those punched rolls of paper, but the MIDI of the 19th century?

Unlike a lot of automotive restomods though, this one is mostly reversible. He did drill few holes and slots in the original wood, but nowhere that it would alter the integrity or original operation of the player piano mechanism. The MIDI-controlled solenoids just poke the same key paddles from below that the pneumatic mechanism used. From the listener or operator’s perspective, unless the doors that reveal the music scroll or lack thereof are open, the piano behaves exactly the same. Except now it has access to the whole wide array of tracks that exist in MIDI form, rather than a paltry selection of hard-to-find piano rolls.

Each of the relays is driven by a MOSFET via shift registers to get 88 outputs out of the single Pi Pico in charge, with a level shifter involved to get the RP2040 speaking 5 V logic. If you’re wondering how that gets volume control, no, the piano isn’t smacking keys at full volume all the time. He’s using the RP2040’s powerful PIO to create a sort of PWM signal to soften the solenoid blows when needed. To save his power supply, he’s also got it set up to stagger the pulses, so multiple relays aren’t pulsed at the same time when the MIDI file calls for chords.

There was actually more overlap between player pianos and MIDI than you might think, given this presentation of an Apple ][ being used to create the piano rolls.

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How To Kill Humidity Sensors With Humidity

An often overlooked section in the datasheets for popular humidity sensors like the BME280 and DHT22 is the ‘non-condensing humidity’ bit, which puts an important constraint on which environments you can use this sensor in. This was the painful lesson that [Mellow Labs] recently had to learn when multiple of such sensors had kicked the bucket after being used in a nicely steamed-up bathroom. Fortunately, it introduced him to sensors that are rated for use in condensing humidity environments, such as the SHT40 that’s demonstrated in the video.

This particular sensor is made by Sensirion, and as we can see in the datasheet it features a built-in heater that allows it to keep working even in a condensing environment. This heater has three heating levels which are controlled via the I2C interface, though duration is limited to one second in order to prevent overheating the sensor.

Of note is that you cannot take measurements while the heater is operating, and its use obviously increases power draw significantly. This then mostly leaves when to turn on the heater as an exercise to the engineer, with [Mellow Labs] opting to start the heater when relative humidity hit 70% as a conservative choice.

In the comments to the video other options for suitable sensors were pitched, including the Bosch BME690 which is similarly rated for condensing environments. All of which condenses down to the importance of reading the datasheet for any part that you intend to use in possibly demanding environments.

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Wearable MIDI Controller Built With Raspberry Pi

Most synths happily get by with keyboard or pad inputs and make lovely sounds in response. [Becky Clarke] and her fellow collaborators are building a synth that works rather differently. DigitSynth is a wearable controller that’s rather fun to interact with.

The heart of the build is a Raspberry Pi 5. It’s set up to talk to a TI ADS1115 ADC chip that lets it read a bunch of analog flex sensors embedded in a right-hand glove, while the Pi can also read a bunch of tactile buttons activated by the left hand. The flex sensors are used to control synth parameters like LFO rate and filter cutoffs, while the buttons control chord changes. The Raspberry Pi runs custom code to read these devices and generate the requisite MIDI commands to send to a Roland JD-Xi synth which is responsible for actually making the sound. Both sets of fingers are also dotted with LEDs for visual feedback, controlled via a TLC59711 PWM driver.

It’s a fun build that creates some ethereal sounds in an intuitive way, thanks to the nature of the interface. We’ve featured some similar builds before, using the flexure of the hand to create musical soundscapes. Video after the break.

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Simple MIDI Sample Player Runs On ESP32

[Jakub] is a musician, and found himself in need of a simple way to trigger samples via MIDI when on stage. So many commercial solutions exist, but most were overkill for the job or too messy and complicated to justify their use in a live environment. Thus, [Jakub] worked up Samplotron to do exactly the job needed with a minimum of fuss.

The project is based around the ESP32. It’s effectively a lightweight hardware sampler that can trigger sounds on command via MIDI. Sample data is loaded from an SD card, which also stores the device configuration. The Samplotron plays back mono 16-bit WAV files at 44,100 Hz, delivering audio via an ES8388 audio codec module connected via I2S. Two encoders are used to control the device, with a menu system presented via an SSD1309 OLED screen. Samples can be loaded and managed via this interface, and it allows tweaks to be made to volume levels and one-shot/loop playback as needed. MIDI input to the device is simply handled via the onboard UART functionality of the ESP32 itself.

It’s a neat little bit of music hardware that does exactly what [Jakub] needs and nothing more. We’ve featured similar builds before, like this neat RP2040 soundboard. If you’re building rad custom hardware for your own musical adventures, we’d love to know all about it. 

A Look Inside The Creative MB-10 MIDI Blaster

Before it became viable to distribute and play music tracks on home computers, the use of FM and Wavetable synthesis was very common, with MIDI Wavetable-based devices like the Roland MT-32 and SC-55 still highly sought after today. The Creative Midi Blaster MB-10 that [Yeo Kheng Meng] reviewed and tore down for an analysis isn’t quite as famous or sought after, but it provides a good example of what Creative Labs was doing at the time in this space.

Released in 1993, it definitely has more of a popular style vibe to it than the utilitarian Roland devices, even if this means highly impractical curves. In the list of features it claims Roland MT-32 emulation, which would have made it quite a bit more useful to the average user, including gamers of the era. Games like DOOM supported these MIDI devices for audio, for example.

In terms of price only the Roland SC-55ST comes close to the MB-10, similarly dropping a screen and a host of features. In terms of features the MB-10 claims far fewer instruments than the SC-55 variants, with even with the slightly higher priced SC-55ST massively outgunning it in raw specs. So would you ever buy the MB-10 back then and consider it a ‘good deal’? If $100 in 1990s money was worth losing full MIDI compatibility for, then it seems the answer was ‘yes’.

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RP2040 Powers A MIDI-Controlled Soundboard

When you’re livestreaming, it can be tempting to fire off all kinds of wacky sound effects like you’re a morning radio DJ back in the heady days of 1995. If that’s who you want to be, you might like this soundboard project from [Biker Glen].

The build is based around an RP2040 microcontroller. It’s paired with an I2S digital-to-analog converter for sound output, which in turn feeds a small amplifier hooked up to a speaker or a line output.  The RP2040 is programmed to respond to MIDI commands by playing various sounds in response, which are loaded off a microSD card. It’s able to act as a USB MIDI host, which allows it to work seamlessly with all sorts of off-the-shelf MIDI controllers like the MIDI Fighter or the Novation Launchpad.

It’s an interesting hardware solution to a problem that you could probably also solve with software on your streaming machine, especially if you’ve already got a USB MIDI controller. However, there’s something to be said for lightening the load when your streaming computer is already doing lots of hard work to truck video up to the cloud already. Files are on Github if you’re eager to replicate the build.

Soundboards are just fun, which is why we’ve featured them before. Meanwhile, if you’re whipping up your own streaming accessories at home, be sure to let us know on the tipsline!