Mittwoch, 13. April 2016

Mantis Robot Arm - Part 1 - The Gripper

This is the first video about my new robot arm called Mantis. Just because of the looks of the eye like encoder:

I plan to do several videos about the assembly. The parts will be listed below. I try to supply you with a link. Besides I'm quite busy now so don't expect soon to many.


Links (some are affiliate links!)
Printed parts
Vitaflex 30
MG 996R

M4 Nut

DIN 125 - 4

Montag, 4. April 2016

Adding an extra display to my laptop.

I bought on of these 9,7" LCD displays about a year ago and and last weekend I finally got some mood to build a case for it. Originally I planed to use it as display for my home automation system but this is currently far away from becoming reality. So I decided instead to use it as second screen on my work laptop I got this one cheap on ebay and since it has a native DisplayPort it's works like a charm.

The case is of course 3D-printed.

The adapter is from and shipped from Japan in a fair amount of time and is working fine. I have an older version as the current one but had no trouble at all.
I mountet the power switch outside but I think this is optional.


Links (some are affiliate links!)
Printed parts
9,7 " Lcd-screen LP097QX1

Displayport and Backlight driver
DisplayPort cabel
USB cable
DIN 7991 M3x8

Freitag, 5. Februar 2016

Building my own onewheel "skateboard"

Since Adam Savage from Mythbusters posted his best gadgets 2015 I fall in love with the OneWheel, but oblivious I would never by one if I can make one by myself. After watching some youtube videos about it, the requirements are not that hard and this is finally the opportunity to build my own motor controller. You can watch the first parts on YouTube:
Here is the CAD model.
The motor sits in the tire, so I needed to design my own rim.

 The rim half will be 3D printed, it's also a nice test how tough the prints will be. The frame is made of aluminium rods. I'm using a 250W electrical bicycle motor I got cheap on ebay.
 To fit inside the tire I had to remove the spokes mounts, luckily we have a fablab with a late in town, so I could remove them:
The Motor will be mounted to the aluminium frame with some rood. I cut a thread in the center and and some counter screws sideways.
I also drilled holes in the motor and mounted screws sideways to mount the 3d printed rim parts. With the basic frame completed it starts looking like something to drive with:
That's all for now, I keep you guy updated about the progress. And I will publish the cad, code and electronics if I'm done. Batteries will be LiFePo4 cells, they are lightweight but high capacity and the best thing compared to normal LiPo batteries are: They can't burn ^^ As motor controller I found a interesting product called TI instaspin-FOC. I cover this topics later.

Sonntag, 23. August 2015

ESP8266 in the wild, WiFi LED controller hack.

Recently I found a cheap (9€) WiFi LED controller on AliExpress:

I bought 2 because I was curious if it would be possible to hack this drivers.

Controller overview:

This pictures show the PCB. As you can see there are pins labeled as RX,TX,GND,3.3V. I simply connected an USB-Serial converter to the pins. The two other pins are GND and GPIO0. If you set a jumper between this two pins, the controller starts in bootloader mode. 

The chip above is a NXP HC245, a 3-state Octal bus transceiver. It is used to drive the N-channel MOSFETS (20N06L - 20 A, 60 V, N−Channel DPAK).

The power supply is a 2 stage design. A AOZ1212 3A Simple Buck Regulator to convert the input voltage to about 5V and an AMS1117 low dropout voltage regulator to get 3.3V.

The pinout for the ESP8266 is as follow (Arduino numbering)
redPIN    12
greenPIN  13
bluePIN   15

// W FET
w1PIN     14
w2PIN     4

// onbaord green LED D1
// onbaord red LED D2

TX GPIO2 @Serial1 (Serial ONE)
RX GPIO3 @Serial

Jumper closed -> start in bootloader mode on Power on.
Jumper open   -> start user program 
I have a simple demo sketch on github:

This can be controlled with openHAB.

You should also take a look at my other ESP8266 project:

Dienstag, 6. Januar 2015

3D printable Robot Arm

This is the first post about my new 3D printable robot arm. It is inspired by well known industrial robots but 3D printed. The overall goal is to build a nearly entirely printable and cheap robot arm with at least 5 degrees of freedom.

I'm currently done with the base section and the forearm. I plan to document this project as a video log on Youtube. 
The first video is about the base section, the second about the forearm:

Rotary plate and conclusion:

I hope you excuse the video and audio quality as I'm still learning this video stuff. 
Of course you can download the stl files from thingiverse:

The parts are completely printed in ABS. This took about a week. I used 12% 3d honeycomb infill and slic3r 1.21e. It's about 1.2kg filament. 

I don't recommend printing them yet as I need different kind of motors. Steppers are not the best solution for a robot. They provide accurate movement but the torque-to-weight ratio is very bad. I will post updates with future developments. 

Next up is the gripper:

Arm moving with DC-Motors:

I started a project:

Donnerstag, 22. Mai 2014

Building my Delta Printer

After I built three Cartesian 3d printers (1, 2, 3) I've decided to move on and go Delta. A friend of mine showed me his and he had absolutely amazing print quality. After I've seen his prints it was clear I needed a Delta 3d printer. I started the design with a hexagon base. My goal was to build a fully enclosed printer, because I want to print mostly ABS - for that you need at least an enclosure or better a heated chamber. Back in the days I was quite a name in the german casemodding scene and building this printer reminded me a little bit of the good old times... and so it went this direction:

For the electronic housing I was inspired by the overall hexagonic design and let my imagination go with it.
It became the unique design pattern from this point forward for the overall printer. It can fit a RAMPS or a RUMBA motherboard and provides a mount for a 80mm fan.

For the autonomous printing there is a 128x64 pixel LCD.
It also features a click encoder for menue selecting and a full sized SD-card slot. Even the filament holder is designed like that, it is also flexible to fit all kinds of spools:
I printed these parts with clear ABS and honeycomb infill. I really like the look of it and how it scatters light.
I think about illuminating this, too ;)

One of the most imported parts of a delta printer are the linear guides. I got a set of three from the friend I mentioned before (the one with the delta that impressed me) for a very good price.
These high quality industry grade linear guides provide a smooth silent and clearance free movement.
The drive system is pretty standard normal 200 steps/rotaion NEMA17 stepper motors and DRV8825 drivers. The belt is T2.5 and the pulleys have 16 teeth.
At the top I used opto endstops for the max length limit switches.

I planned the effector carriage to fit an E3D-V5 hotend in it. My cooler design features one hotend fan in the front and two additional fans for print cooling.

Talking about the effector, I also added a Z-Probe for automated bed leveling:
If the probe is not used, it is stored in the upper position (left picture) and held there by a magnet. If you need the probe on the bottom surface, there is an even stronger magnet that will pull out the probe pin. The measurement is again done with an opto switch.
If you are not familiar with delta calibration read these two articles:
As print surface I use a special coated aluminum sheet and a 160 Watts heat pad:

The other very critical parts are the moving joints. I used igubal® rod end bearings with female thread,
Type KBRM-03.
The arms are made of carbon fiber tubes. With JB-weld I glued a M3 stainless steal threaded rod in the tube and also a M3 nut on every end. Everything is covered by heat shrink tube: 

The arms have to be very carefully aligned to avoid print issues later: 

To get enough torque for the bowden extruder I used a NEMA23 stepper motor as I did with my last printer.

I had quite good experience with this design and didn't change much.

The enclosure is made of birch plywood. I used pigmented wax to get the dark color:
I really love this pigmented wax, it protects the wood without losing the wooden feel when you touch it. It is also surprisingly easy to use. You only have to apply it with a cloth wipe. It covers really homogeneous and much easier than paint.
For the top surface I used the laser engraver I built last year to add a nice hexagon decal, this is not only nice to look at, it really helps to cut the parts precisely.

 It's quite hard to photograph because the deacels are more or less only visible under a specific angle:
I tried to engrave one before and one after waxing but the difference is minor.

The door of the enclosure is made of acrylic. This can easily bend to a needed angle with a hot air gun or a gas burner. It has to be mounted and should bend to a proper surface. I made a simple wooden form with the right angle. You can see it in the video below:

The hinge is a piano hinge you can buy in every home store. It comes in a length of about 1,5 m and can be cut in fitting pieces. The mount threads are directly cut in the acrylic. After a week of printing I discovered some minor cracks on the surface. Carefully heating the surface again hopefully will fix this.

The hole inside is covered by 2 mm thick EPDM foam rubber. It closes the gaps and looks great. I hope it absorbs the noise a little bit. The heated build plate delivers enough power to heat air inside the printer to about 45-50°C with the door closed. Since I primary print ABS it's a perfect environment.
To illuminate the print I used normal 300 LEDs/m led stripes.
For additional noise reduction I put the printer on 25mm large rubber feats:

Overall I'm very happy with the results. It's a beautiful machine and the print quality is very good. Calibration wasn't that hard. I really recommend building a delta if you already have a 3D-printer:

Here is a collection of the separate files I put to download. There are more to come but I'm still cleaning up some minor design errors:
My longest print until now is the rhomball form Gorge W. Hart.
It took 36h21m and is made of "glow in the dark ABS". It has a diameter of about 18 cm and weights about 350 grams.
I added some support and of course you can download it here:

There are a million pictures of the overall build and design here: G+ DeltaStar photos
and pictures of my first prints here: G+ DeltaStar prints