Here is a tune I would like to play on my trombone. It looks quite easy so it won’t take long to learn. It was written by a Russian composer whose name I can’t pronounce, far less spell. It’s meant to sound like a bumblebee buzzing around a garden and the piece is quite fast.

If you would like to hear what it should sound like, click on the image. This will take you to a website where there is lots of free music to download. Keep practicing!

Line tracking robot – update

Today I have made a new track for it and it’s a lot bigger, with more places to go. Luckily, it more or less goes the same way every time!

(It isn’t very easy to draw with your finger! I’ll use text next time.)

I’ve made a video with it driving around and it’s probably easier to understand.

And here is a link to some other line following robots.

Line tracing robot

Tracking Robot Car
Sold by: sanurety  from Amazon


The kit arrived well packed and complete. The only problem was that the instructions were in Chinese! A quick search using Google found excellent instructions in English. But don’t throw the Chinese instructions away!!!

Everything required to build the robot was in the kit – except for batteries. Two AA cells are required. The integrated circuit came with a socket to prevent it being damaged by the soldering process.


I started by identifying the resistors and inserting them into the printed circuit board. This wasn’t very easy as the colour codes on the resistors were not very clear and confusing as they had five bands instead of the usual three. The colours were also difficult to decipher. Fortunately we had a multimeter and could measure the resistor values or else we would have had to guess!

As this was my first soldering project I managed to persuade my Great Uncle to help me. He is old enough to remember the day that Marconi invented the radio. After a few lessons I was able to insert components and solder them in place.

All the other electronic components were easy to identify and solder onto the circuit board apart from the LEDs. Although the instructions said that the short component lead was the anode it didn’t help if you were unaware of which end was which on the schematic diagram.

The battery holder and the motors were attached to the circuit board using heavy duty double sided adhesive pads. You must be very careful that the motors are lined up with the edge of the board before pressing them down as they are not designed for any future adjustment.

Getting the motors to turn in the correct direction is a matter of trial and error and involves swapping the connections to each motor in turn. It is best not to screw the wheels on before you do this as the robot is likely to run off the table in an unpredictable direction.

The last thing to do is to solder in place the two optical detectors that control the direction of the robot. These are soldered to the underside of the board on either side of the front castor and face downwards.

Once everything was in place we switched the robot on to test it – IT DIDN’T WORK!!!


We found the problems were mainly down to dodgy solder joints and one motor LED which was possibly fried by the soldering process. A word of caution though, the tracks on the circuit board are not robust enough to stand up to repeated soldering attempts and the component pads can easily become detached from the board and break the circuit.


Once we had fixed the problems we were ready to test the robot’s line following capabilities. This is where you find out why you must keep the Chinese instructions – printed on the back is an oval test track! We put the robot on the track and switched it on and IT WORKED PERFECTLY!

The next thing to do will be to find a thick black marker pen and to make a larger more exciting obstacle course for the robot.


  • Packaging: 4 stars
  • Quality: 3 stars
  • Instructions: 0 stars
  • Ease of construction: 3 stars
  • Value for money: 5 stars

Pros: It was quite cheap (cheaper if you buy it direct from China).

Cons: No instructions / confusing resistors / poor quality circuit board.