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3D Printing / Re: MKS Gen L 1.0
« Last post by jimmyeao on Today at 12:15:32 PM »
Hi All,
I have an MKS GEN L with some TMC2208s (Wired in UART mode), I upgraded to this when the board in my Ender 3 died - everything working really well apart from PID tuning, I can't get a stable extruder temp (was rock solid on the Creality board). It fluctuates by +-3 degrees. Now when printing PLA @208 it's not too bad, but when I push the temp up to 245 for PETG, it never settles, hence printing never starts.
I have run a PID tune already but it doesn't seem to have improved much after flashing the new values. Is it possible I have a bad board or have I missed something fundamental?

Thanks  :)

Walking / Animabot Rev3 - Advanced Hexapod Robot
« Last post by Nemesis on January 17, 2019, 09:34:32 AM »

Hexapod Robot Animabot is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Animabot is an advanced hexapod robot created to be a human companion and interact with people and objects.
If I do my job well, he will be able to talk, play with a ball, recognize you,  take care of the home when I'm not here,  be remote controlled and much more !

This will be the third and last version of this robot... I started this project quite some time ago (in 2001) and I think it is time to at least finish one version of it :D
The concept is still the same and most of the exterior design will remain similar to the Rev2. However, the hardware and mechanical will greatly improve !

Improvements from Rev2:
   • SLA 3D printed body
   • Overall body design improved
   • 4 Layers Single Motherboard for better performance and size reduction
   • All sensors are I2C and on the same bus
   • Improved battery charger
   • Improved Power supply
   • Efficient active cooling
   • Improved communication between STM32 and Rpi
   • 2 axis Head (new feature !)
   • 2x Oled display for the Eyes (new feature !)
   • 2 moving ears (new feature !)
   • Gesture sensor on top the the head for better interactions (new feature !)
   • Docking station capable (new feature !)
   • Flexible Oled display for robot status (new feature !)
   • Hidden Raspberry Pi with moving hood (new feature !)

Components & Characteristics:
   • Energy: Li-Ion 11.1V 7800mAh
   • Power: Custom 140W PSU based on LM25119PSQ
   • Charger: Custom, based on LTC4015
   • Brains: STM32F415VGT6 + Raspberry Pi 3 B+
   • OS: RTOS + Raspian
   • Programming Language: C, Python
   • Communication: 2x Bluetooth + WiFi
   • Vision: 5Mpx Micro Camera
   • Displays:
      - 2x 0.49" OLED for the Eyes
      - 1x 1.81" Flexible OLED for robot status
   • Actuators:
      - Legs: 18x Herkulex DRS-0101
      - Hood: 1x KST DS215MG
      - Head: 2x KST DS215MG
      - Ears: 2x Hitec HS-40
   • Sound: 2x 1W stereo speakers + buzzer
   • Light: 1x RGB status Led
   • Control: Autonomous and Remote-controlled
   • Sensors:
      - 1x Gesture Sensor
      - 1x IMU 10-DOF
      - 2x LM75B temperature monitor   
      - 1x IR telemeter(GP2Y0A21)
      - 1x Magnetic switch for charging dock     
   • Target environment: indoor/outdoor
   • Size [LxWxH]: 28cm x 36cm x 12cm
   • Weight: 2,5kg

   • Mechanical design : 60%
   • Mechanical assembly : 0%
   • Hardware design : 90%
   • Hardware assembly : 0%
   • Firmware on STM32 : 30%
   • Firmware on RasPi : 10%
   • Material & Components : 70%
   • Applications : 0%

As mentioned, now Animabot is only composed of 1 motherboard instead of several which help a lot on 2 points: performance and compactness.
The PCB is divided in 4 main areas:
Front: Power Supplies (7.4V - 5V - 3.3V)
Middle: IMU + Cortex M4 + Interface (Bluetooth, buttons)
Rear: Battery Charger
Edges: Connectors

The Power supply is based on a LM25119 from Texas Instrument and capable of delivering 2x 10A at 7.4V, that's over 140W !!!
Of course, to dissipate all this power you need a proper cooling system... this is why the PCB is equipped with a "wind tunnel" cooling directly the PSU and the Charger ;)
The charger evolved as well and is now capable of Telemetry, I will be able to supervise the input and output energy of the Battery. The charger also takes care of the standard protections (over-charge, battery temperature, under-voltage, etc..) and all the monitoring/configuration is done via I2C !
I also overdimensioned most of the components like the transistors to be sure to be on the safe side.

I also removed the ATX Raspi from the robot and the Raspberry Pi will be controlled by the CortexM4 directly for powering ON & OFF. To avoid the last noise issue on the speakers, I added a small isolated DC-DC converter for the audio amplifier.
As mentioned, all the sensors are now connected together on the same I2C bus, which should improve and simplify the data acquisition (one function to gather all sensors data). The IR telemeter as well, I use a small I2C ADC converter to do the trick.

Board dimensions [LxWxT]: 177mm x 84mm x 1mm

Mecha Design:
Coming soon ;)

Tutorials / PLX-DAQ
« Last post by BaldwinK on January 16, 2019, 06:44:18 AM »
Diagnostic help when coding is often achieved using the console print facility of the microprocessor. However, when there is a lot of data, the resulting torrent washing over the screen soon becomes meaningless.

A free download from Parallax Inc provides a link into Excel which shares the same USB port for the console. Either the IDE or PLX-DAQ can be connected, but not both together.

Why Use This?

My ongoing project to make a quadruped walk has nearly been abandoned more than once. Not being able to see exactly what is going on inside a complex distributed system makes progress very difficult.

So I took some time out to write routines to create better tools for the job in hand. This extra work has helped regain focus on the main issues. It shows what can be done, but it is surely well over the top for most needs.

 [ You are not allowed to view attachments ]

Each slave Nano holds information about the four motors under its control. The master runs a background task to enquire about one set at a time so as not to interfere with normal working. With a cycle time of 15mS this means all the display areas are updated every two seconds or so.

So facing the bot we see information for the Heel, Knee, Pitch and Roll/Rotate motors in each leg. On the screen left centre are the Input angles written into the slaves and at the top are the achieved Deg angles as measured by the servo pots. Excel is set to colour any differences of more than 2 degs.

Bottom left we see the Max permitted PWM values written into the slaves. Duty shows the PWM moving average values measured over one second. Motors are driven at twice the nominal voltage so these checks are important. Again Excel is set up here to colour any value over 80.

Entering 16 angles to test one posture can be time consuming. PLX-DAQ also allows for values to be taken from the spread sheet and sent on. The green boxes are for such use and can be used, or not, with switches in the master software. Best to disconnect whilst making changes to a number of fields.

To the right we have more green boxes for Calibrating the total build of the bot. This allows the position of each motor spline to be aligned with the limb as required. Ref shows the slave register value which will eventually be transferred to the slave default startup code.

Top right are values for IK experiments. Each slave can calculate the angles (Input) given IKx and IKy in mm. Ikw controls the Roll/Rotate motors.

Lastly there are two spare blocks of display; best to code these up front as adding sections later is a pain. Each foot switch FSw shows ground contact and is useful in determining terrain and construction inaccuracies.

The master Nano has direct contact with an IMU for Pitch and Roll info. The User1 tick box is handy for stepping through sequences.

PLX-DAQ Messaging

The download includes a good help file which explains the protocol. Here we see how a simple change to a print string can make a difference to the display appeal.

  Serial.print ("CELL,SET,"); 
  Serial.write (excol);             //byte value ASCII D
  Serial.print (PLXrow);            //integer value 20
  Serial.print (",");
  Serial.print (PLXduty);           //integer value 81
  Serial.println (",");

This sets the value 81 into cell D20 to display HR Duty P.

  Serial.print ("MSG, 100 tiltR ");   
  Serial.print (tiltR); 
  Serial.print ("  tiltP ");   
  Serial.print (tiltP); 
  Serial.println (","); 

This might write 100 tiltR -0.2  tiltP 16 into the diagnostic message line.


A bit trickier here because the protocol is asynchronous and without message numbering or acknowledgement. We send a request then must wait patiently for a response. I include a timeout and then move on if it fails to arrive.

  Serial.print ("CELL,GET,");     
  Serial.write (excol);
  Serial.print (PLXrow); 
  Serial.println (",");             //send request for cell value
  if (Serial.available() > 1)
  setpoint = Serial.parseInt();     //parse reply

I have found PLX-DAQ an invaluable tool and highly recommend it.
Stationary / Re: Four Motor Leg Module
« Last post by BaldwinK on January 09, 2019, 04:55:14 PM »
Sorry I missed your message hence being late in replying

I have done a lot of work with the MPU and found various funny issues. Pitch and roll are easy to work out against gravity but yaw is in quite the wrong plane.  The MPU-6050 tries to guess the yaw from the pitch and roll so can mess up when not used in a drone or boat. In the tutorials I tried a Quarternion Mimic and you can see the motion like water going down a plug hole when it messes up. The real problem is that these sensors only work in a hemisphere and for general leg control there can be a sudden reversal of vectors.

Again in the tutorials I showed a DIY Yellow Servo using a cermet pot. For me the plastic gears could not deliver enough torque but could be usable for a smaller project.  Yes, your legs do look very similar - very smart.

I have been stripping MG996R servos and using the 260:1 metal gearbox with a Nano in control of motor positioning. Much stronger but a real hassle to get legs walking without stumbling.

General Discussion / Re: Android Adware
« Last post by Diegotorry on January 08, 2019, 05:34:48 AM »
Glad to have people like and talk like this like me.
Introductions / Re: Hi, Mushroom glue here.
« Last post by Diegotorry on January 08, 2019, 05:31:52 AM »
Like to study or follow stories like this I like to talk about it.
CAD / Re: Solid Works maker license 1 year Free!!
« Last post by maelh on January 04, 2019, 01:50:08 PM »
Thanks! I wish I had the time and disk space, but I'll keep it in mind for later!
CAD / Solid Works maker license 1 year Free!!
« Last post by tinhead on January 02, 2019, 06:15:07 AM »

Found this on discord prusa channel:

code: 918MAKER

Enjoy free solidworks... windows only but hey it's free!
General Discussion / Re: Merry Christmas
« Last post by Protowrxs on December 28, 2018, 11:44:25 PM »
Late to the party but Merry Christmas Robot Rebels! I hope to build and post a bit more in 2019!

General Discussion / Ultralite or flying car of sorts
« Last post by Impala on December 27, 2018, 09:30:02 PM »
Ultralite or flying car of sorts

Pages: [1] 2 3 ... 10

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* Recent Topics

MKS Gen L 1.0 by jimmyeao
[Today at 12:15:32 PM]

Animabot Rev3 - Advanced Hexapod Robot by Nemesis
[January 17, 2019, 09:34:32 AM]

PLX-DAQ by BaldwinK
[January 16, 2019, 06:44:18 AM]

Four Motor Leg Module by BaldwinK
[January 09, 2019, 04:55:14 PM]

Android Adware by Diegotorry
[January 08, 2019, 05:34:48 AM]

Hi, Mushroom glue here. by Diegotorry
[January 08, 2019, 05:31:52 AM]

Solid Works maker license 1 year Free!! by maelh
[January 04, 2019, 01:50:08 PM]

Merry Christmas by Protowrxs
[December 28, 2018, 11:44:25 PM]

Ultralite or flying car of sorts by Impala
[December 27, 2018, 09:30:02 PM]

Web TIme API - by Gareth
[December 07, 2018, 04:34:37 PM]

API Directory by Gareth
[December 06, 2018, 03:34:16 PM]

The Original Prusa I3 Mk3 by tinhead
[November 30, 2018, 02:49:52 PM]

Email notifications by CraigCox
[November 28, 2018, 10:26:06 PM]

And another one. by CraigCox
[November 28, 2018, 10:17:54 PM]

This kids a freaking genius by ossipee
[November 21, 2018, 04:55:40 PM]

* Recent Posts

Re: MKS Gen L 1.0 by jimmyeao
[Today at 12:15:32 PM]

Animabot Rev3 - Advanced Hexapod Robot by Nemesis
[January 17, 2019, 09:34:32 AM]

PLX-DAQ by BaldwinK
[January 16, 2019, 06:44:18 AM]

Re: Four Motor Leg Module by BaldwinK
[January 09, 2019, 04:55:14 PM]

Re: Android Adware by Diegotorry
[January 08, 2019, 05:34:48 AM]

Re: Hi, Mushroom glue here. by Diegotorry
[January 08, 2019, 05:31:52 AM]

Re: Solid Works maker license 1 year Free!! by maelh
[January 04, 2019, 01:50:08 PM]

Solid Works maker license 1 year Free!! by tinhead
[January 02, 2019, 06:15:07 AM]

Re: Merry Christmas by Protowrxs
[December 28, 2018, 11:44:25 PM]

Ultralite or flying car of sorts by Impala
[December 27, 2018, 09:30:02 PM]

Re: Merry Christmas by tinhead
[December 27, 2018, 05:15:54 AM]

Re: Merry Christmas by Impala
[December 24, 2018, 04:34:27 PM]

Re: Merry Christmas by MEgg
[December 24, 2018, 06:56:46 AM]

Merry Christmas by jinx
[December 24, 2018, 03:18:32 AM]

Web TIme API - by Gareth
[December 07, 2018, 04:34:37 PM]