Let's Make Robots!

My artificial neuron approach

February 12, 2015

A single artificial neuron can represent some simple Boolean functions like OR, AND or NAND and some like XOR not, because a single artificial neuron can only learn linearly separable mappings.

Example. Perceptron for the AND function:

Automatic medical diagnosis device - Part 1

One of my long term projects is to develope an automatic medical diagnosis device. During my research I came up with the so called naive Bayes classifier and started to learn about this kind of machine learning. In the attached PDF I use the example given on the wikipedia page but in greater details. If you want to learn more about naive Bayes classifier, I recommend the following one: http://guidetodatamining.com/guide/ch6/DataMining-ch6.pdf


Laser range finder hack

Today I found  a PLR 15 laser range finder from Bosch for 45 Euro in a German DIY store. I bought and disassembled it to see if it could be used as a laser ranger finder in robotics. The main issue will be to debug the communication protocol. I hope it outputs distance measurements over serial directly like the UNI-T UT390B.


I am writing an OS for my future robots. So far the system is more or less a simple CAS (Computer Algebra System). The idea is that not only the user can use the CAS, but also the robot itself. It can solve linear and quadratic equations, includes linear regressions and a simple scientific calculator. The standard order of operations (1. exponents and roots, 2. multiplication and division, 3. addition and subtraction) is used. For the equation string parser I conceived a simple algorithm.The string will be simplified till only addition is left. Example:

Pulse oximeter Mk II

I just started to build a second version of a pulse oximeter. If you don't know what a pulse oximeter is, here is a simple but detailed description what a pulse oximeter is and how it works.


Today I found this in a local Carrefour store in Qingdao for 70 RMB. It has two RGB LED's which illuminate the ears and a couple of buttons. When certain buttons are pressed, it plays some songs or speaks some text (in Chinese).

I will probably hack it and build an emotional/chat robot out of it. In a first step I will take it apart and see what's inside (if my daughter let me...)

Interactive Stochastic Learning Automaton - cleaned up code

I have cleaned up the interactive Stochastic Learning Automaton code I once wrote and attached it in this short blog. Just send '0' or '1' via serial monitor, if a chosen action was favorable or unfavorable and see how the automaton learns to chose the right action over time.

T-800 reloaded

A funny afternoon in the office, some robot talk, and one of my Chinese artwork girls with some photoshop fu came up with this (it's me!)

That said, I really want to build a life-sized humanoid robot...And it will kill us all!

Simple 4 pixel camera sensor

In the following I describe a simple 4 pixel camera sensor, which can be versatilely used in robotics.

The sensor consists in general of four pin photo diodes with a relatively large photo sensitive area, arranged in a square, and an according collimator lens. Every photo diode can be thought of a quadrant of a two dimensional graph. We can use the sensor to measure the intensity of light, detect motions, track a light source in two dimensions or do basic 2-D optical flow calculations.

COSMA's brain

Attached you find the Rev. 0 schematic of COSMA's brain (Eagle). This board connects directly to a FTDI  board. As I need MOSI, MISO and SCK also for the micro SD card, I added solder jumpers, so those pins are not connected to the SD card/voltage level shifter while burning the bootloader on the chip.

The board mainly contains:

- ATMEGA2560