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: