Dynamic Range MIDI Foot Pedal
prusaprinters
<h3>About</h3><p>I was looking to buy a MIDI pedal with a good range of motion and a fairly low price (mainly to control virtual instrument's expression/volume while my hands are on the keyboard, and my right leg is on a sustain pedal).</p><p>I didn't find what I was looking for, so I figured it's a good motivation to improve my CAD skills, and make my own.</p><p>My idea was to let the user choose the range they want, so... this pedal supports up to 80 degrees. While not expected to be fully used (I know I don't have that flexibility) different ranges work for different positioning of the pedal, and personal comfort.</p><figure class="image"><img src="https://media.printables.com/media/prints/272769/rich_content/b8e4a891-a56a-450d-8443-8a374887336f/animation.gif#%7B%22uuid%22%3A%2256a0a7eb-cb2c-491f-92df-786ecb7a8969%22%2C%22w%22%3A640%2C%22h%22%3A360%7D"></figure><h3>Behavior</h3><ul><li>By default, the full range is used.</li><li>A press on the blue side-button initiates range selection mode, which is enabled for 5 seconds. It's indicated by a blue light, and can be ended sooner, by an additional press on the button.</li><li>Range is chosen by moving the foot pedal back and forward, over the desired range.</li><li>After the range is set, it is saved to EEPROM (so it's not power depended).</li><li>Movements in the range are indicated by the green light (indicating MIDI commands are sent to the host) while movements outside of the range, are ignored.</li></ul><h3>Software</h3><p>Developed in C with the Arduino framework.</p><p>Code can be found <a href="https://github.com/nadavh/dynamic_range_midi_foot_pedal/blob/main/code/foot_pedal_arduino_mini.ino">here</a>.</p><h3>Hardware</h3><p>Mostly 3d printed (PLA) and split to avoid support material, and to be strong (in terms of printing orientation).</p><p>You can print the “part_groups” 01 and 02 (3mf or stl), or download the parts separately.</p><p>There is also "assembly.step", to help you customize the design.</p><p><strong>Additional parts:</strong></p><ul><li>Arduino Micro.</li><li>10 x 12mm M3 screws, washers and nuts.</li><li>2 x 608 (8 x 22 x 7mm) bearings.</li><li><a href="https://www.aliexpress.com/item/Free-shipping-50pcs-lot-size-12X12X7-3-push-button-Led-Tact-Switch-illuminated-switch/1428645429.html?spm=a2g0s.9042311.0.0.366c4c4dAUs27O">Micro switch with LED</a>.</li><li>B100K potentiometer (e.g. <a href="https://www.aliexpress.com/item/1005001421294754.html">https://www.aliexpress.com/item/1005001421294754.html</a>).</li><li>A glue of your choice (I've used hot-glue).</li><li>15 x Padding stickers (optional).</li></ul><h3>Assembly</h3><p><strong>Notes:</strong></p><ol><li>All screws will be connected from the top (with washers) to nuts at the bottom (of the relevant part).</li><li>The computer-generated images below don't show screws and wires (because I was too lazy to model them. Sorry about that).</li><li>I've used these externally available models:<ol><li><a href="https://grabcad.com/library/arduino-micro-1">Arduino Micro</a></li><li><a href="https://www.thingiverse.com/thing:4242664">Potentiometer</a></li></ol></li></ol><h4>Steps:</h4><ol><li>Solder 3 wires to the potentiometer (15cm each. You can cut them more precisely later).</li><li>Connect the potentiometer to the potentiometer_holder (Use glue): <img src="https://media.printables.com/media/prints/272769/rich_content/9492818d-5e8c-48c7-ae7c-5fedd1b20d09/s2_1.png#%7B%22uuid%22%3A%222fb553ea-1f50-437f-8119-4d67a9a698dd%22%2C%22w%22%3A480%2C%22h%22%3A270%7D"><img src="https://media.printables.com/media/prints/272769/rich_content/1abb5327-59ea-41bd-80df-40f0ed9aa16b/s2_2.png#%7B%22uuid%22%3A%220ff3fa5d-2185-434c-a690-21281f1dd5f4%22%2C%22w%22%3A480%2C%22h%22%3A270%7D"></li><li>Connect the potentiometer_gear to the potentiometer (make sure it's tightly coupled with the shaft): <img src="https://media.printables.com/media/prints/272769/rich_content/a030200d-17e0-40be-a622-b3b88fa9c180/s3.png#%7B%22uuid%22%3A%22de2209d0-f28e-43a1-a152-dc57a5559b47%22%2C%22w%22%3A480%2C%22h%22%3A270%7D"></li><li>Connect the potentiometer_holder to the base_plate, using 2 screws. Don't tighten the screws too much (allow the potentiometer_holder to slide on the rail, for later adjusments): <img src="https://media.printables.com/media/prints/272769/rich_content/28bd954f-34ab-49ab-9d27-835ed4d30384/s4.png#%7B%22uuid%22%3A%22e9a50751-13d5-499f-a2bc-68622b32f850%22%2C%22w%22%3A480%2C%22h%22%3A270%7D"></li><li>Connect the 2 bearings to the left and right bearing holders: <img src="https://media.printables.com/media/prints/272769/rich_content/11857a52-0647-49ca-ae01-8a331cb6326a/s5_1.png#%7B%22uuid%22%3A%22e100651c-7360-46fa-a941-c6b134c31490%22%2C%22w%22%3A480%2C%22h%22%3A270%7D"><img src="https://media.printables.com/media/prints/272769/rich_content/179fcbae-cc4f-4722-adb6-8d90684e8265/s5_2.png#%7B%22uuid%22%3A%22b3a28379-d468-4a77-8082-6847aac33484%22%2C%22w%22%3A480%2C%22h%22%3A270%7D"></li><li>Connect the right_bearing_holder to the base_plate with 2 screws: <img src="https://media.printables.com/media/prints/272769/rich_content/7297aa16-ab93-43a5-b05c-84cd7933f70e/s6.png#%7B%22uuid%22%3A%229769fb8b-dafa-402f-be86-02207fca7147%22%2C%22w%22%3A480%2C%22h%22%3A270%7D"></li><li>Connect the rod_gear to the rod. <img src="https://media.printables.com/media/prints/272769/rich_content/039c0b9b-ee39-42da-856e-62b0ca20d900/s7.png#%7B%22uuid%22%3A%2205fcd133-6812-4ae4-985b-45eaba6abb96%22%2C%22w%22%3A480%2C%22h%22%3A270%7D"></li><li>Push the rod through the bearing of the right_bearing_holder. Make sure it's oriented correctly, so that the rod_gear's teeth connect to potentiometer_gear's teeth when both gears are aligned: <img src="https://media.printables.com/media/prints/272769/rich_content/897db3bd-ebe5-40fa-a807-102e38761a11/s8.png#%7B%22uuid%22%3A%228ede4359-a67b-4d7a-abd6-d5ff6321a548%22%2C%22w%22%3A480%2C%22h%22%3A270%7D"></li><li>Connect the left_bearing_holder to the base_plate with 2 screws, pushing the other side of the rod into the left bearing: <img src="https://media.printables.com/media/prints/272769/rich_content/d6adbb27-4f97-4f81-8912-cd3580aca4fb/s9.png#%7B%22uuid%22%3A%22254ba09b-8aff-4dc8-90e0-eb5250915d2a%22%2C%22w%22%3A480%2C%22h%22%3A270%7D"></li><li>Make sure that rod_gear is aligned to the potentiometer_gear, and that a bit of the rod sticks from both sides of the bearing holders.</li><li>Connect both left and right rod connectors to the rod: <img src="https://media.printables.com/media/prints/272769/rich_content/d782273e-41ee-4485-abba-bc426a68e9a8/s11.png#%7B%22uuid%22%3A%22fa8a1839-5fc5-43a8-bbfa-548fe5043f88%22%2C%22w%22%3A480%2C%22h%22%3A270%7D"></li><li>Put the pedal on the left and right rod connectors, and connect the screws, <strong>without </strong>connecting the nuts: <img src="https://media.printables.com/media/prints/272769/rich_content/1ba2a4e1-e707-4e50-97c9-588dfd8ebe09/s12.png#%7B%22uuid%22%3A%2291c201eb-4506-42e2-886a-1c962543249e%22%2C%22w%22%3A480%2C%22h%22%3A270%7D"></li><li>Move the pedal back and forth, making sure both gears are in contact. Correct the angle of the potentiometer_gear, so that it moves together with the rod_gear and doesn't block it from moving the whole range of the pedal.</li><li>Disconnect the pedal from the rod connectors, and tighten the potentiometer_holder screws: <img src="https://media.printables.com/media/prints/272769/rich_content/d1d64fae-9a4e-4b09-b021-bf0e780a087e/s11.png#%7B%22uuid%22%3A%22eab9e065-c319-4064-ace5-be1babffba59%22%2C%22w%22%3A480%2C%22h%22%3A270%7D"></li><li>Solder potentiometer wires to Arduino (The picture below is from the finished assembly. In this step you only need to solder the marked wires):<ol><li>Potentiometer top wire -> Arduino GND</li><li>Potentiometer middle wire -> Arduino A0</li><li>Potentiometer bottom wire -> Arduino 5V <img src="https://media.printables.com/media/prints/272769/rich_content/848a048a-016d-44ac-b71d-b3b03e41f787/s15.png#%7B%22uuid%22%3A%225b221857-5d53-4542-b130-3e0caefc0322%22%2C%22w%22%3A477%2C%22h%22%3A263%7D"></li></ol></li><li>Solder micro_switch to Arduino (The picture below is from the finished assembly. In this step you only need to solder the marked wires):<ol><li>LED minus & one of the button pins -> Arduino GND</li><li>Other button pin -> Arduino pin 2</li><li>LED plus -> Arduino pin 3 <img src="https://media.printables.com/media/prints/272769/rich_content/bbe7670c-f9f2-4847-bdeb-1306f71e44d6/s16.png#%7B%22uuid%22%3A%22d0308a94-02d7-46f3-a5b7-569bc8e7c270%22%2C%22w%22%3A475%2C%22h%22%3A567%7D"></li></ol></li><li>Connect the micro_switch to the base_plate (use glue): <img src="https://media.printables.com/media/prints/272769/rich_content/3319e90e-add2-487c-97ef-188c07535794/s17.png#%7B%22uuid%22%3A%22a4ccc4e3-fed8-414a-94ce-e9de23d4e4b1%22%2C%22w%22%3A480%2C%22h%22%3A270%7D"></li><li>Connect the button_holder to the micro_switch and base_plate (use glue): <img src="https://media.printables.com/media/prints/272769/rich_content/493d4315-14ef-4c41-986e-5dcb8a20ad9e/s18.png#%7B%22uuid%22%3A%2267efebfe-c1fb-4422-a23d-e7fcb4b78f2b%22%2C%22w%22%3A480%2C%22h%22%3A270%7D"></li><li>Connect Arduino to the base_plate (use glue): <img src="https://media.printables.com/media/prints/272769/rich_content/c9d92e82-ca61-4fbe-94c9-d6cfea61bdb7/s19.png#%7B%22uuid%22%3A%22dea94417-9ab6-4594-8dc2-e6ef64517e6d%22%2C%22w%22%3A480%2C%22h%22%3A270%7D"></li><li>Reconnect the pedal to the rod connectors with screws and nuts.</li><li>Add rubber pads: <img src="https://media.printables.com/media/prints/272769/rich_content/76be81d6-c9fe-40c7-ae34-0cf91e8432a3/s21_a.png#%7B%22uuid%22%3A%222a5bda80-5334-48f0-b79d-d694fc10a2e6%22%2C%22w%22%3A480%2C%22h%22%3A270%7D"><img src="https://media.printables.com/media/prints/272769/rich_content/2dd640cb-79cf-4fdb-a00e-4d63c6838cfa/s21_b.png#%7B%22uuid%22%3A%225a0903be-358a-4a36-9cc8-aa797bdf8991%22%2C%22w%22%3A480%2C%22h%22%3A270%7D"></li><li>You can optionally add a pad to the button, to make it easier to press with your other leg.</li></ol><p>Have fun!</p>
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