InMoov Finger Starter (including a servo-safer option)

thingiverse

Hello InMoov Starters, This Finger Starter project is a unique blend of various "Things". Firstly, it's a redesign from Gaël's Finger Starter kit, which can be found at http://www.thingiverse.com/thing:67709. Secondly, I've combined Mats Servo double track Pulley design, available at http://www.thingiverse.com/thing:1074604. Thirdly, I'm utilizing my first servo pulley design, which can be seen at http://www.thingiverse.com/thing:1052776. A key difference between Gaël's design and mine is that this one is slightly longer, allowing for the option to use a spring in line. This spring enables the option to secure the servo mechanically when the Finger is pulling. With the spring, it's also possible to use smaller servos like the CS238MG, which are strong enough and weigh half as much as standard servos. The inclusion of two different sizes of pulleys makes this design even more versatile. Both pulleys are identical, but they have different mounting options for the servo. The CS238MG servo uses M2.5 screws, while a standard servo requires M3 screws. I've also included Hitec/Futaba spline 25 teeth-based pulleys that work similarly to Mats double track pulley designs. However, I'm using a single track and my pulleys are not symmetrical, which helps reduce power consumption from the servo. When the Finger is getting closer to closing, the pulley becomes smaller, resulting in better power usage from the servo. Here's a video showing the initial test without the spring: https://youtu.be/HaEzM8pp8b0. During a quick test, the CS238MG servo used a maximum current of 6mA even when holding down the finger, demonstrating that the servo-safer works effectively. To complete this Finger Starter kit, you'll need the FingerIndex files from Gaël, which can be found at http://www.thingiverse.com/download:1027899. For basic assembling information, please refer to Gaël's website at http://inmoov.fr/finger-starter/. For mounting a standard servo or the CS238MG servo adapter, I used four M4 x 12mm screws. The SC238MG servo is secured with two M3 x 8mm screws, and the Arduino is attached using M3 x 6mm screws. Print Settings: Printer Brand: Ultimaker Printer: Ultimaker 2 Rafts: No Supports: No Resolution: 0.1mm Infill: 35% Notes: The Finger_Starter_Spring STL can be printed with a resolution of 0.15mm and an infill of 30%. Custom Section: All parts needed are... Optional spring (mechanical servo-safer) First, pull the rope sideways... Next, push both pulley parts together... To keep the rope in place, use the screw for a moment... The next step is mounting the pulley to the servo. Make sure the servo is set to its finger-open position (Counter-Clockwise). The easiest way to do this is by using the "Knob" servo sketch: Controlling a Servo Position Using a Potentiometer by Michal Rinott modified on 8 Nov 2013 by Scott Fitzgerald #include <Servo.h> const int potpin = A0; int val; Servo myservo; void setup() { myservo.attach(9); } void loop() { val = analogRead(potpin); val = map(val, 1024, 0, 180, 0); myservo.write(val); delay(15); } When the pulley is in place, it looks like this... Next steps are to add the finger... Part 1... Part 2... Part 3... Tie a knot in both ropes with enough extra length (which we need at the pulley side !) Cut the rope and pull it tight. Use an M3 screw with a ring to lock each rope.