5V 5mW Laser Sensor Module for Arduino 650nm

Ok, calling it a sensor is a bit off… as it only is cabable of beeing turned on and off again. Measurements for a 0.85 EUR device would be a real surprise, but hey – the cats still love the beam which is easily mountable to an robotic arm consisting of two 28-BYJ stepper motors 🙂

 void setup ()
 {
   pinMode (13, OUTPUT); 
 }

void loop () {
    digitalWrite (13, HIGH); / / open the laser head
    delay (1000); / / delay one second
    digitalWrite (13, LOW); / / turn off the laser head
    delay (1000); / / delay one second
 }

 

Arduino microphone sensor analog + digital

I tried a small arduino microphone recently:

int sensorPin = A0; // select the input pin for the potentiometer
int ledPin = 13; // select the pin for the LED
int sensorValue = 0; // variable to store the value coming from the sensor
 
void setup () 
{
  pinMode (ledPin, OUTPUT);
  Serial.begin (9600);
}
 
void loop () 
{
  sensorValue = analogRead (sensorPin);
  digitalWrite (ledPin, HIGH);
  delay (sensorValue);
  digitalWrite (ledPin, LOW);
  delay (sensorValue);
  Serial.println (sensorValue, DEC);
}

Output looks like that:

22
20
22
22
22
21
22
22
21
22
22
22
22
22
22
22
21
22
22
21

 

Well explaination how sound sensors work:

Youtube Video

DIY WLAN sauna thermometer for 10 EUR with ESP8266 and DS18B20

I recently built an WLAN Thermometer which needed to be partly whaterproof and support temperatures under 0 and over 85 degrees celsius. Therefore the usual temperature measurement chips like DHT11 or LM35 couldn’t be used, especially as the surrounding circuits might be damaged by the steam of the sauna environment. After a while I found the DS18B20, which has an metalic and whaterproof end and perfectly matches the requirements. In china the one-wire-supporting chip currently costs around 2 USD and comes with a 1m whaterproof cable.

The ESP8266 works with 3,3 Volts which isn’t very common among my old power adapters which is why I soldered a chinese version of the AMS1117 (an Lm2596 step down controller) on the board, which enables the setup also to be run by USB cable as you can see on the pictures.

Screenshot_2015-12-30_16-26-31For the webinterface I wrote a small external javascript file, which gets called by the esp8266 on most web requests. It fetches the temperature by json and visulizes it with d3.js in real time. The scales fit to the measured temperature and time automagically. It further is possible to display the site on multiple clients without loosing data or performance.

That was my useful christmas holiday project 🙂

Code on github.com

docker-compose wordpress with rerun-able volumes

There are several tutorials and files for running wordpress in docker. For me nearly none of them worked, therefore i wrote my own rerunable docker-compose file, which I like to share here now:

wordpress:
  image: wordpress
  container_name: wordpress
  links:
   - mysql
  ports:
   - "80:80"
  environment:
    WORDPRESS_DB_USER: root
    WORDPRESS_DB_NAME: wordpress
    WORDPRESS_DB_PASSWORD: "ch4ngeThis!"
  volumes:
    - /var/www/html/
mysql:
  image: library/mysql:latest
  mem_limit: 256m
  container_name: wordpress-mysql
  environment:
    - MYSQL_ROOT_PASSWORD=ch4ngeThis!
    - MYSQL_DATABASE=wordpress
    - MYSQL_USER=wordpress
    - MYSQL_PASSWORD=ch4ngeThis!
  volumes:
    - /var/lib/mysql

Just put this code into docker-compose.yml, change the passwords accordingly and run a new wordpress simply by:

docker-compose up

HC-SR04 rosserial range publisher

I tried to re-implement my hc-sr04 rosserial setup which i described here and couldn’t find the source of this attempt.  I therefore redid it and now sharing the results.

The simple wiring setup:

wiringThe output on rviz:

rviz_outputand new the source on github.

You can start the publisher with:

rosrun rosserial_python serial_node.py /dev/ttyUSB0

Complex Low-Cost Robotics – Lighting Talk at Datenspuren 2015

Hi there, I did a small lightning talk at the Datenspuren 2015. I expect the talk to be recorded but not published yet. All videos will be available at the Dataspuren Recordings Page. But in case you want to show the slides to somebody download them here.

UPDATE
Talk is online (my part starts at min 37:45) . Because linking didn’t really work, I cut the original video and uploaded my five minutes to youtube. The talk is in German, but I’ve added english subtitles:
Youtube Video

To see the mentioned robot in action, you can see this little video I posted some time ago.

Youtube Video
Do not hesitate to contact me, I am kinda available to hire and traveling through vienna the next week 🙂

3D Printing from pain to fun

After a long period of ups and downs and a relationship which best gets described as “complicated” with my Mendel Prusa i2 the results are really getting better and therefore also bigger. It also starts ti feel like fun to print stuff instead of beeing tensed up all the time.

So today I printed a fillament holder roll, which when assembled consists of two bearings and a plastic bearing holder (8*3*4cm). I also got in touch with blender to edit the STL files other than the non linux Sketchup, which lately tends to produce broken CAD models which cause slic3r to crash.

See the results below:

 

Making Robots Talk and Video

Today I watched a really nice talk about making robots. It’s worth every minute and ideal to dive into the current issues of current robotics by showing different approaches to solve common problems. Therefore the participants are:

  • Russ Tedrake Director, Center for Robotics, MIT Computer Science and Artificial Intelligence Lab
  • Sangbae Kim – MIT Biomimetic Robotics Lab
  • Mick Mountz – Founder, Kiva Systems
  • Gill Pratt – Program Manager, DARPA Robotics Challenge, DARPA Defense Sciences
  • Marc Raibert – Founder, Boston Dynamics
  • Radhika Nagpal – Self-organizing Systems Research and Robotics Group, Harvard University

Youtube Video

Six legs two Motors

Hexbug 477-2423 – Scarab XL


Youtube Video
available on amazon for 25€ 🙂

Random thoughs in Lego