Ultrasonic transmitter

Speaking robot

Circuit diagram

IC-DY936A

Q1,Q2-SS8050

R1-K

R2-300K

R3-10K

R4-1.5M

R5-100OHM

C1-101

C2,C4-104

C3-220uF-16V

LED-2

Speaker-8ohm

Toy motor

Electronic MIDI drum

Circuit diagram

This circuit is a MIDI interface between drum pads and computer or hardware 

sequencer. Using this circuit you can hit pads with drumsticks and store the 

MIDI data in real time.This circuit is based around the PIC16C84 microcontroller 

which scans the inputs on RB0 to RB7 and when a high is detected the 

software transmits the equivalent note-on ( and then the MIDI note-off after a 

short delay) for the required drum sound on the MIDI output on RA0.

Simple digital AM transmitter

Circuit diagram

Here is a very simple AM transmitter, anything spoken in front of the mic. Can be listened Medium Wave radio reciver  within the range of few meters.

This circuit is very as it contains only One IC , Two Resisters , Two capacitors and a Mic. And can be built by any new electronic hobby with expense of just a few dollars

This circuit contains a Timer IC 555 and a few Resistance, Capacitors, A mic. And an antenna.

This circuit can transmit AM radio wave in MW frequency of around 600 Kilo hertz.

The circuit uses a power of 9 voltage and around 100 mili amperes. You can use a 9v battery for the power supply.

The Timer IC 555 is used a free running multi vibrator which have been adjusted in frequency of 540 Kilo hertz.

The sound signal is inputted to pin number 5 of IC from the condenser mic And The IC converts the signal to a Amplitude modulated frequency and outputs from pin number 3 from which an Antenna of length of around 2-3 meters converts the frequency to radio waves which can be received by any Medium Wave radio receiver by tuning it to around 600 Kilo Hertz from a distens of up to 25-30 meters.

You can also make the transmission frequency of this circuit variable by using a Preset Resistor instead of R2 and a Gang condenser instead of C1.

Part list

Resistance:                         Value:

R1                                         380 ohms.

R2                                          1 Kilo ohms.

Condensers:                        Value

C1                                         0.001 Micro farad

C2                                         1000 micro farad /   25 volt.

Semiconductors:

IC1                                        Timer IC 555

Others:

Condenser Mic.

An antenna or wire of length around 2-3 meters   , 9v battery Etc.

Light following robot

Circuit

No programming or microchips!

---

Robots, the most awesome thing there is, especially when allot of people can build it!
I got this robot from a friend as a present. thank you Rudolf.

Anyway, this robot uses 2 Light dependent resistors to sense light and drive toward it.

Warning,
Soldering iron->hot->hurts

That said, lets start

the reason this is green: the battery's i used are rechargable, one battery can load 1000 times so i save 1998 battery's in this instructables

PS: you have to have SOME electric knowledge for this.