Due to the popularity of the original idea, I decided build something a bit more robust and portable. I wanted something that would be battery powered so I could practice on my phone, using a portable key, almost anywhere in the world. Therefore I designed the system where plugging in the jack switches the unit on. The LED acts as a battery monitor, and the button as a Bluetooth reset switch. Full manual is available over at the Github for this project.
Engineering Drawings & Models
Build of Materials
I’ve included links to purchase most of the parts at Adafruit for ease of purchasing. Not all parts are as pictured.
|Adafruit Feather 32u4 Bluefruit LE||Main Board||1||Link|
|FeatherWing Proto – Prototyping Add-on For All Feather Boards||Add-on Board||1||Link|
|Header Kit for Feather – 12-pin and 16-pin Female Header Set||Headers||1||Link|
|Break-away 0.1″ 36-pin strip right-angle male header (10 pack)||Headers||1||Link|
|Lithium Ion Polymer Battery Ideal For Feathers – 3.7V 400mAh||Battery||1||Link|
|Neutrik NMJ6HCD2||Switching Jack||1||Link|
|Diffused RGB (tri-color) LED – Common Anode||LED||1||Link|
|4 Pin 2.54mm Dupont Housing||Connector||1||Link|
|Female 2.54mm Dupont cable – pre-terminated > 40 mm||Main Board to Jack cable||4||Link|
|2.0mm JST-PH JST Connector||Power Connector||1||Link|
|Through-Hole Resistors – 1.0K ohm 5% 1/4W||Resistor||1||Link|
|Tactile Switch Button||Reset Switch||1||Link|
|6 mm Black Nylon Screw – M3||Case Screws||8||Link|
|30mm Black Nylon Standoff – M3||Case Standoffs||4||Link|
|6 mm Black Nylon Screw – M2.5||Main Board Mounting Screws||8||Link|
|10 mm Black Nylon Standoff – M2.5||Main Board Mounting Standoffs||4||Link|
|Misc Multicoloured Silicone Wire||Wire||1||Link|
|3mm Custom Plexiglass Top Case||Case||1||Widely Available|
|3mm Custom Plexiglass Bottom Case||Case||1||Widely Available|
Proto Board Build
Mount the components, route wires and solder onto the Proto board.
After all the wires are attached, then solder on the female headers on the Proto board and male headers on the Feather.
Build the jack assembly. I opted for a 1/4″ jack over an 1/8″ as jack sockets on rigs vary and it’s more robust to use a jack adapter 1/4″ down to 1/8″ rather than 1/8″ to 1/4″.
The case is simply just a cut and drilled piece of Plexiglass or a simple 3D print job. I have created a PDF template that can be printed and glued to the Plexglass protective film with spray mount to make cutting and drilling easier. Make sure to verify dimensions prior to spray mounting.
- Start by mounting the standoffs to the Feather board
- Mount the Feather board to the bottom case
- Mount the standoffs for the top case to the bottom case
- Mount the jack assembly into the top case
- Attach the battery to the Proto board
- Gently press the Proto board assembly onto the Feather board
- Slide the top case on whilst ensuring that the 4 pin Dupont connector from the jack is firmly seated
- Follow the instructions from the original project to program the board
- Follow the manual to setup for iOS