Upgraded hardware, potential pre-order store.
4 months ago
– Fri, Jul 12, 2024 at 09:21:38 AM
Hi everyone, good news! Since the day the campaign was funded I've been hard at work exploring options for potential upgrades to the MIDI Goblin's hardware. There's been a lot of experimentation over the last month, using various components and pin layouts for the esp32.
Here's a small list of changes and upgrades...
1 - screen upgrade!
Previously MIDI Goblin was using a .98", i2c, oled display - this has been changed to a 1.3 inch SPI oled display. Although .98", i2c displays are great because they occupy few esp32 pins and are very cheap - they are quite slow and teeny tiny.
The new 1.3", SPI, display is quite large and much, much, much faster. Although the new displays are more expensive and modifying the case will also cost a chunk of change - it's easier to read makes projects that require faster refresh rates viable, so its well worth the investment in my eyes. Although the new screen occupies more pins on the esp32, I've evened that out with the next upgrade
2 - multiplexer!
The buttons are all now being read through a multiplexer. This little component has 16 channels and frees up a lot of i/o pins on the esp32 previously occupied by individual buttons. And since it has 16 channels and MIDI Goblin only had 15 buttons...
3 - everyone's getting an extra button!
The encoder (knob) of the MIDI Goblin has been upgraded to an encoder with a built-in button. It turns out they're pretty affordable and widely available components. Having an extra channel available on the multiplexer worked out perfectly.
4 - arp button replaced with user defined button
Although I liked the idea of being able to turn off and on the arpeggiator using the ARP button, MIDI Goblin does waaay more than just arpeggiate, so this button will now be labelled as "user 2"...the old "user 2" button will be changed to user 3. So now there are 3 user defined buttons. It just makes more sense and you can always defined it as the on/off button for the arpeggiator if you like.
5 - new encoder - easier makes life easier
The new encoder can be turned in either direction endlessly and has a button as well so I'm currently modifying the navigation and value editing logic to take advantage of this. You can use the encoder to scroll through menus and press its button to select options but you'll still be able to use the up/down/left/right and yes buttons to achieve the same results..its really satisfyingly to scroll through menus with.
6 - new PCB(circuit board) and available i/o
Of course making all of these hardware changes has required creating a new PCB for the MIDI Goblin itself. There are a lot of things to take into consideration when choosing the pin layout of an esp32 project. Each pin does different things. If you're familiar with an arduino pinout diagram then you'll understand what I mean. A full diagram of the MIDI Goblins esp32 pin assignments will be made available on https://www.midigoblin.com in the future.
To be clear - MIDI Goblin will only have 5 pin midi in and out connections, an encoder, 16 buttons, a nice 1.3inch oled display and the usb c connection of the esp32 itself.....but if users want to modify their case and add things like....audio in and out jacks, touch sensors, buttons, devices that require analog input/output - ill be making all of the un-used pins from the esp32 available on the PCB(along with extra grounds and 3v pads) clearly labelled so users can modify their midi goblins...hopefully people take advantage of this and create their own devices...esp32's are quite powerful so I wouldn't be surprised if someone manages to turn a midi goblin into a full blown synth.
7 - pre-orders
Quite a few people who missed the kickstarter have messaged me asking if they could pre-order a MIDI Goblin - I'm considering this. I might actually make this possible soon through a service like backerkit.
Right now my focus is on ensuring the Kickstarter backers receive their units on time (shipping in October) and that the MIDI Goblins that ship are above all expectations . Once I'm confident the kickstarter backers will be getting the best possible product without any delays - I'll open a pre-order store...this will be sooner rather than later.
-Andrew