Let's Make Robots!

Durga Puja

This isn't robot related at all. Pardon me if I have chosen the wrong place to post this.

Durga Puja, or the worshipping of Goddess Durga, is the greatest festival of Bengal, the place where I live in. See what Wiki has to say about it here.


This is my one motor walker robot. I thought I should make a water boat. But since the challenge already has such an entry ,I decided to build something new. And … Read more
Navigates Around, behaves as my best buddy!
This is a robot I have built recently. Here are some pics. This is finished DS   Read more


Two days back I got a parcel. It was from Thailand,and to my surprise it contained 5 pcs of TQFP32 to DIP breakout boards. First of all I was confused as Ladvien resides in US and he told me that he might send something.

Thanks a lot ladvien,will post pics soon. This is my first SMD soldering. Have soldered three MCUs on them. I shall be glad if I can be of any help to you. Thanks again.

Long Live LMR   .....................ALABTU !!!!!!!!!!!!

I have some Atmega QFN and TQFP chips lying around for quite a long time. I was pretty eager to use them,but there should be some type of QFP to DIP converter for … Read more
Follows light and avoids obstacles
Using a
Oh,I thought a lot for the name of this bot,finally decided to name it CLIMBEX. Climex is a kind of beetle, and since it can climb small obstacles, I gave it this … Read more

The LM-317 Voltage regulator problem

Well, recently I have been attracted to laser diodes. I am trying to make them work. Here is what I learnt-

1. LASER diodes are pretty current hungry,it will eat as much as it gets,since it's internal resistance is pretty low.

2. To make LASER diodes work properly, you need a CONSTANT current source.

3.Red Laser diodes need 3 - 4 volt to run.

4.You can make a Laser driver using LM-317 (it's called DDL)

Mic Preamp + Power Amp problem

Hello everyone,I want to build a system so that when I talk over a tiny electret mic,my voice gets amplified and comes out of a speaker (I dont know what are these systems called , Police use them to alert,announcers use them too). All I've done so far is that I've built an electret mic preamp out of BC xxx transistors,and a 10W power amp out of TDA2003 IC. BOTH are running great individually. But whenever I connect the output of the mic to the power amplifire stage,it doesn't work anymore...And in addition to that there are feedback oscillations too.

Identifying LASER diode pins

I have found a Sony AD-7280S DVD-RW drive,and the laser inside it is in working condition. I have taken it out,but surprisingly it has three pins. I want to know the pinouts of this specific diode. As reverse current for the Laser diodes is only 10uA max,I can't take the risk of trial and error method. The laser Diode has the three pins named as "D","G","C". I wonder what do these letters stand for.