1 year ago

Fred's Left Hand Part 14

All the files for this project can be found on the http://inmoov.fr/ website
The Inmoov robot was designed by Gael Langevin and released as Open Source under the creative Commons Attribution-NonCommercial 3.0
The hand being built in this project is the Version 2 hand or the i2-Hand.

Over the last 13 parts we built the forearm, the hand, instlled the servo, tendos, springs, sensors, servo driver, PSU for the servos and installed it all onto the robot.
In Part 14, lets connect the 5V power for the sensors and servo driver control chip.

So a little bit of a disclaimer.
During the initial testing, I could not work out why the system wasn't working.
The answer, I forgot to connect the power for the sensors and driver board.
This is the first time I have used the TCA9548A I2C Multiplexer.
Let hope it works :-)

In Part 1, I decided to use PTEG. For the forearm, most of it is a standard build except for the modified wrist.
In Part 2, I used a few nutserts and installed the servos.
In Part 3, I started on the version 2 hand its self.
In part 4, I installed the 5 Hall sensors and the springs.
In Part 5, I installed the electronics and the PTFE tube
In Part 6, I installed and wired the PCA9685.
In Part 7, I add the Elbow gear and connect all the tendos to the servos.
In Part 8, I test out the MPU6050 and the finger sensors.
In Part 9, I mount the bicep servo and 20A SMPS to the back of the Bicep.
In Part 10, I connect the forearm to the bicep and setup the pot and bicep servo, testing the joint with a servo tester.
In Part 11, I attached the assembled arm to the shoulder on Fred.
In Part 12, I wire up a board with terminals to connect the various feeds to the TCA9548A I2C Multiplexer.
In Part 13, I install the module I wired up last week into Fred's Back

Link to the Calibrator part: http://inmoov.fr/wp-content/uploads/2019/01/Calibrator.stl
20A SMPS Mount: https://github.com/Cyber-One/Fred_Inmoov/blob/main/Parts/20A_SMPS_Mount_V2.stl

The PTFE tube are 1.5mm ID and 2.5mm OD with the following lengths:
Thumb 335mm
Index 300mm
Middle 300mm
Ring 300mm
Pinky 360mm

The 12 core ribbon wire used has the following wire assignments
1 - Servo Power - 6V
2 - Servo Power - 6V
3 - Servo Power - 6V
4 - I2C VCC - This is the I2C Bus power 5V
5 - I2C SDA - Serial Data
6 - I2C SCL - Serial Clock
7 - I2C Output Enable - Not Yet Used
8 - I2C Gnd
9 - Spare conductor for secondary I2C VCC
10 - Servo Gnd
11 - Servo Gnd
12 - Servo Gnd

The Spare I2C VCC on wire 9 is planning for the future.
The MPR121 is a capacitive touch sensor that would add to the ability of the hand to sense its environment, however it's max power supply is 3.5V, well below the Hall senors 4.5V minimum.
When MRL supports this chip, we can supply it with 3.3V and use the same SCL, SDA and Grd wires.
Up to 4 of these devices can be on the same I2C bus.

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