Building a robot cart (Experiment 32 of Make:Electronics) finished

In my previous post about the robot cart I described how I finished the cart and tested the circuit on the breadboard. I only had to solder the circuit to the perf board and mount the board on the cart. Simple, right. Unfortunately it wasn’t that simple. After soldering I tested the board and discovered […]

Building a robot cart (Experiment 32 of Make:Electronics)

This experiment is about building a little robot cart. Make:Electronics describes all the steps that needs to be taken in great detail beginning with the cart and then the circuit. This experiment is a lot of work but I think it is worth it because you make a complete robot from the bottom up. The cart […]

Breadboard malfunction (redo experiment 29 and 30 of Make:Electronics)

During experiment 29 and 30 of Make:Electronics I noticed that the circuit was very susceptible to noise to the point that it really interfered with the experiments. While thinking about it I suspected that something was wrong with the breadboard. I decided to redo both experiments with a another breadboard (but without the low pass […]

Fuzz: experiment 30 of Make:Electronics

After some refurbishing around the house I’m finally back with Make:Electronics. In experiment 30 I used most of the circuitry from experiment 29. The idea is to create a distorted sound. The base of an NPN transitor receives the output from the 555 timer thus controlling the base of another NPN transistor (see fig 5-55 […]

Audio filtering, experiment 29 of Make: Electronics part 4 (finished)

I finally reached the second stage of Experiment 29 of Make: Electronics. In the first stage I used an audio amplifier (TEA2025B) and a coil to create a crossover network. During this first stage the source of the audio was an iPod (read here). In the second stage the iPod was replaced by a 555 […]

Audio filtering, experiment 29 of Make: Electronics part 3

A small update on the filtering experiment 29 of Make: Electronics that I wrote about earlier this week. To improve audibility especially of the lower frequencies I had to built an enclosure. The book proposes a plastic box but I had a shoebox made out of cardboard lying around. I cut a circular hole in […]

Audio filtering, experiment 29 of Make: Electronics part 2

Finally, after earlier setback, I’ve got the amplifier and 4-inch speaker working properly. I tried multiple setups today and managed to get rid of the distortion. The book dictates 9V, 33K resistance on audio input. This results in my case in a temperature of 90 degrees (194 fahrenheit). Which is uncomfortably high. I therefore decreased […]

Audio filtering, experiment 29 of Make: Electronics part 1

This experiment of Make: Electronics demonstrates the use of self-inductance and capacitance in audio filtering. The low and high frequencies of the audio signal can be separated and send to different speakers (woofer and tweeter). The audio chip used for this experiment is the TEA2025B, a somewhat older chip that was used in portable radio […]

Self-inductance, Experiment 28 of Make: Electronics

After making an improvised coil (experiment 25) and cutting a coil out of a speaker (experiment 27) in this experiment the self-inductance of a coil is demonstrated. As a coil in this experiment I used 44 meters of coated copper wire on a spool.  In parallel with the coil two low current LED’s are connected. […]

How a speaker works, Experiment 27 of Make: Electronics

I couldn’t get the cylindrical neodymium magnet of the required size so I skipped experiment 26. Next experiment 27: Loudspeaker Destruction of Make: Electronics is a very simple and very short experiment but worthwhile nevertheless. It demonstrates how a loudspeaker works by literally cut it to pieces. Luckily I had an old 2 inch speaker […]