let's make robot bugs from scrap materials
Date: Monday, November 04 @ 04:45:15 EST
These robot bugs are simple creatures made from parts taken from old cdrom drivers. .
It is very fun to work on theese tiny little things. .
At least two switches and three DC electric motors are present in every cdrom driver. All of these parts are suitable to be used in our robot bugs..
In my design, two (nearly) identical DC motors are being used. You may see similar structures at other bugs on lots of robot sites on the web..
My bug is something like this; .
Both motor axles directly in contact to the ground. In this way, it will be possible for the small and weak motors to move the bug without using any reduction gear.
Though motor axles are made of high quality steel, there will be no timely problem of wearing out.
The motor axles tips are our bug's wheels. And they are small, so the bug needs a smooth surface to go properly. If the surface you have to use is not smooth enough, that is not a difficult problem to solve either. U may just plug a plastic gear or plastic pipe on to the axle tips or only wind some electricians' isolating band around them. I've tested these methods all, they work good
The circuit has got 4 transistors and 2 resistors .The curcuit schematic is below. A very simple one as you see. But u may be sure it won't work if you directly solder it to a board before testing on a protoboard. Because it is highly dependent on the properties of the light dependent resistor (LDR)
Two LDRs are used for making the eyes. Two LDRs resistance should be matching. Otherwise robot will turn around itself continuously. Best way is to buy a number of (say 10-15) LDRs, find and use the most matching pair by measuring their resistance before assembling the circuit. while measuring, the light level must be nearly equal. With the eyes, robot will avoid shadow and walk around under the sun. For this bug, staying in the shadow means running out of power and dying. Fortunately it is enough to put it back under the sun to continue its life.
Later i've made a simpler circuit with only one resistor and a transistor (for each motor). Here it is. And the rule is the same, test it, before soldering it.
That's all for now. I had better work on my new robot. Dont hesistate to as your questions if you have any.