Unipolar Motor Controller

Unipolar Motor Controller

Two circuits will be built today to control Unipolar motors. A unipolar motor is a type of step motor described as needing only a current source. By contrast, bipolar motors require two current sources to move. The complexity of this type of motors is that they are powered by DC current sources and require digital circuits so that the energizing …

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DC Motor Controller

DC Motor Controller

Today we will build a circuit to control DC motors. Electric motors of all kinds work thanks to electromagnetism. They convert electric energy into mechanical energy. DC motors are relatively simple control motors. They are motors that have two modes of operation and that allows them to rotate in both directions depending on the way the polarity of the DC …

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Timer with 555

Timer with 555

Today we will build a circuit that is a timer. The IC 555 was used. This was set to Mono-stable mode. When the button is pressed the time starts and the LED lights up. After a while it goes off. To calculate the time the LED is lit the following formula is used: t = 1.1 * C * R where C …

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Obstacle detector using Infrared

Obstacle detector using Infrared

Today we will build a circuit that detects the interruption of an infrared beam allowing an alarm to be created. The LM358 IC has two comparators. Pin 3 which is the non-inverted end of the voltage comparator is connected to the photodiode and the inverted pin (pin 2) is connected to a 10K variable resistor. The output of the comparator …

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Infrared LED Alarm

Infrared LED Alarm

Today we will build a circuit that detects the interruption of an infrared beam allowing an alarm to be created. The LM358 IC has two comparators. Pin 3 which is the non-inverted end of the voltage comparator is connected to the photodiode and the inverted pin (pin 2) is connected to a 10K variable resistor. The comparator output is connected …

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Shutdown button for Raspberry PI

Shutdown button for Raspberry PI

Today we will build a small circuit that lets you execute commands in Raspberry Pi to do whatever we want when a button is pressed (in our case to start the shutdown process). This circuit is quite simple and requires only one resistor and one button. Some LEDs have been added for Raspberry PI to be able to give feedback …

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ADC for Raspberry PI

ADC for Raspberry PI

Using an MCP3008 IC we will add the ability to read analog values on a Raspberry Pi. The Raspberry Pi unlike the Arduinos natively has no way of reading analog data. By adding an integrated as the MCP3008 we can give you this capability. The MCP3008 is a 10-bit Analog-to-Digital Converter (ADC) with 8 channels. This means you can read …

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Signal Meter (VU Meter)

Signal Meter (VU Meter)

Today a circuit will be built using an LM3915 IC and it will visually represent the intensity of an audio signal. The LM3915 has an amplitude of 30 dB and the 10 LEDs are activated in 3 dB intervals. If you want to have an even larger scale can pair several LM3915. See the datasheet on how to do it …

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Doorbell

Doorbell

Today a circuit will be built to make a two-tone doorbell. We will use two ICs, one CD4060 which is an oscillator with a 14-step binary counter and a CD4001 that implements 4 NOR ports. The first integrated will divide the frequency and will be the sound generator. The second integrator will be responsible for converting the frequency and ensuring …

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Logic Probe

Logic Probe

Today we will build two circuits that work as logic probes that inform us of the state of the signal under analysis through LEDs. One circuit uses the IC CD4001 and the other uses the IC CD4011, the first implements 4 NOR ports with Buffer and the second one implements 4 NAND ports with buffer. Using a probe (which is …

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