Friday, December 26, 2014

Simple cassette player amplifier


This circuit is a simple amplifier of the audio signal comming out directly from a magnetic head of a cassete player (like the ones used for cars, before the CD era). The design is focusing on simplicity and not on generating a high fidelity output, which is also depending on the quality of the cassette (tape). This amplifier differs from most audio amplifiers based on common opamps because it uses an LNA opamp (low noise amplifier), due to the fact the audio source has microvolt level (uV). Amplifying a uV voltage without adding internal noise is not an easy task. Note that the output of a microphone has a mV voltage level so it's easier to use common opamps for the amplification.

Saturday, January 18, 2014

Weird legged PCB Robot

This is a simple but weird robot build entirely with veroboards (stripboards).
The robot is standing on two free running wheels and it has two legs that are pushing it like a small cart.
Characteristics
  • CPU: Basic Stamp 2. Board of Education
  • Motion: Two legs with 3 degrees of freedom each (Each leg looks like a PUMA manipulator, without the end effector tool). Two free running wheels are used at the frontend (no extra motors).
  • Motors: Six small servomotors (1.5 Kg). Three motors on each leg.
  • Sensors:
    • Eyes: Two infrared transceivers at the front, for object avoidance.
    • Ears: Two microphones. Capability to detect sound direction.

Soccer and Sumo Robot???

OK, this is a new design I am working on. It's a small robot with a kicking mechanism, a grip and a lot of other cool stuff (e.g. BlueTooth and the ability to control it with an Android app, the ability to charge it to a charging base and much more). This is the prototype and I built it for the tests. Curently I am working on the new improved PCB's
It is Arduino based
I have also some thoughts of implementing a txtzyme style language or a visual style programming using Blockly (or maybe I will combine those two techniques)