Experiment 21: Race to Place from Make: Electronics describes a circuit useful for a quiz show like Jeopardy. Pushing a button lights an LED and locks the button of the other player(s). The two player schematic is depicted in figure 4-95 on page 208 of the book and is built around the 74HC32 logic chip […]
Tag: electronics
After having done most of the circuitry of Experiment 20 yesterday today I connected the relay and all loose wires from the keypad to the circuit. I had to read the description of some of the experiments with relays earlier in the book Make: Electronics (e.g. experiment 7) again to be able to wire the relay […]
Experiment 20 of Make:Electronics describes a hardware device that protects a computer (or any other electrical device) from being used unless a specific numeric code is entered on a keypad. The experiment is built around two 7400 logic chips (74HC08 and 74HC04). These chips process the input from the keyboard and trigger a 555 chip […]
With experiment 19 of Make:Electronics I’m entering the world of pure digital electronics. This experiment explains the basics of the 7400 family chips. It is also a prelude to experiment 20. First an LM7805 voltage regulator is used to to provide precisely 5 volts DC. Then a simple circuit is built around the 74HC00 chip […]
While working on the Atari Punk Console I reread the part of chaining chips in Experiment 17 of Make:Electronics (pg167). I then realized that I didn’t do all the experiments that are described in the book. Since Experiment 17 contains a lot of information and chaining 555 chips is common practice in electronics I decided […]
Before entering experiment 19 of Make: Electronics and the ‘realm of pure digital electronics’ I decided to do an analog project first. I want to make a Stepped Tone Generator aka Atari Punk Console. This piece of electronic is a very basic synthesizer, probably the simplest that one can create. The circuit was first published […]
I (almost) finished the reaction timer today. That means that the delay is build in. This was done by adding yet another 555 timer now in monostable mode. It is triggered with a tactile switch connected to pin 2 of the timer (see pg. 178 of Make:Electronics). During testing of the circuit the LED switched […]
Previously I added 555 timer in astable mode to generate pulses for the counter chips. In the next step a second 555 chip is added. This timer runs in bistable mode (see pg. 176 of Make:Electronics). The purpose of this timer is to freeze the counting when the tactile switch is pressed (figure 4-40 of […]
The next step in Experiment 18 of Make:Electronics is the addition of a 555 timer in astable mode to the circuit (pg. 175 of the book). This addition drives the decade counter therefore the tactile switch that was connected to pin 1 of the first decade counter from the previous part of the experiment had […]
Last Friday I’ve built the circuit as displayed in figure 4-37 (pg. 174) of the book Make:Electronics. The circuit consists of (in my case) three Kingbright 7 segmented digits. Each digit was connected to a 4026 decade counter. The decade counters are coupled by connecting the output of pin 5 (carry) to the clock input […]