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Alex the Giant

Member Since: March 1, 2016

Country: United States



Electrical Engineer

Programming Languages

  • Python

  • C/C++

  • HTML

  • Javascript

  • CSS


University At Buffalo 2008-2013


  • Fixing things until they're broken

  • High voltage

  • Tinkering



Check out our latest tutorial on levitating magnets and creating a wireless light!

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In this week's Enginursday, we'll explore how to use both cores of the ESP32, and why you might want to.

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Let's talk about a PCB design error and troubleshooting the root cause.

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This week I'm getting back to my OLED clock, and discussing the changes I've made.

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Using a ESP32 Thing and a WiFi camera to create a robot that you control from your browser.

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Sometimes troubleshooting requires you to think both literally and figuratively "outside the box."

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This week Alex designs an OLED clock using the ESP32 Thing.

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In this week's Enginursday, Alex meets with a local Speech-Language Pathologist to talk about how makers can help make devices for people with special needs

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In this Enginursday, we'll explore some of the problems that can creep up when connecting I2C devices

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Setting up a sensor to text you if your basement is in danger of flooding

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Create your very own levitating light with just a handful of parts.

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A new twist to the classic party game, Beer Pong!

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Magnetic Levitation

November 20, 2019

This tutorial will show you how to build a magnetic levitation circuit using common parts.

XBee3 Thing Plus Hookup Guide

August 22, 2019

Get started with SparkFun's XBee3 Thing Plus - both the u.FL as well as the PCB antenna versions.

LiPo Charger Plus Hookup Guide

May 30, 2019

This tutorial shows you how to hook up and use the SparkFun LiPo Charger Plus board.

Buck-Boost Hookup Guide

May 10, 2019

This tutorial shows you how to hook up and use the SparkFun Buck-Boost board.

Using Home Assistant to Expand Your Home Automations

May 9, 2019

An introduction to Home Assistant, an open source home automation hub.

ESP32 Thing Plus Hookup Guide

March 7, 2019

Hookup guide for the ESP32 Thing Plus using the ESP32 WROOM's WiFi/Bluetooth system-on-chip in Arduino.

AST-CAN485 I/O Shield (24V) Hookup Guide

February 14, 2019

The AST-CAN485 I/O Shield is an Arduino shield that will allow the user to interface the AST-CAN485 Dev Board with 24V inputs and outputs, which expands its usefulness into industrial systems.

RedBoard Turbo Hookup Guide

January 24, 2019

An introduction to the RedBoard Turbo. Level up your Arduino-skills with the powerful SAMD21 ARM Cortex M0+ processor!

Introduction to MQTT

November 7, 2018

An introduction to MQTT, one of the main communication protocols used with the Internet of Things (IoT).

I2S Audio Breakout Hookup Guide

September 6, 2018

Hookup guide for the MAX98357A I2S audio breakout board.

Qwiic Differential I2C Bus Extender (PCA9615) Hookup Guide

May 31, 2018

Learn how to extend the range of your I2C communication bus with the Qwiic differential I2C bus extender (PCA9615 ) breakout board.

WiFi Controlled Robot

May 2, 2018

This tutorial will show you how to make a robot that streams a webcam to a custom website that can be remotely controlled.

Noisy Cricket Stereo Amplifier - 1.5W Hookup Guide

April 26, 2018

A hookup guide for the Noisy Cricket Stereo Amplifier - 1.5W.

Adjustable LiPo Charger Hookup Guide

September 28, 2017

The SparkFun Adjustable LiPo Charger is a single-cell lithium polymer (LiPo) and lithium ion battery charger. Because it’s adjustable, this charger will be able to safely charge all of our singe-cell batteries.

ESP32 Thing Power Control Shield Hookup Guide

June 9, 2017

This tutorial shows you how to get started with the ESP32 Thing Power Control Shield.

Roshamglo Hookup Guide

March 13, 2017

This tutorial provides everything you need to know to get started with the Roshamglo badge.

TMP102 Digital Temperature Sensor Hookup Guide

February 2, 2017

How to connect and use the SparkFun Digital Temperature Sensor Breakout - TMP102 with an Arduino.

Wireless Joystick Hookup Guide

January 5, 2017

A hookup guide for the SparkFun Wireless Joystick Kit.

Mini GPS Shield Hookup Guide

December 15, 2016

A hookup guide for the SparkFun Mini GPS Shield.

Reducing Arduino Power Consumption

November 10, 2016

A tutorial about different ways to reduce the current draw for your next Arduino project the easy way.

9DoF Sensor Stick Hookup Guide

August 25, 2016

How to connect and use the SparkFun 9 Degrees of Freedom Sensor Stick with an Arduino

Load Cell Amplifier HX711 Breakout Hookup Guide

July 22, 2016

A hookup guide for the HX711 load cell amplifier breakout board
  • The LED is rated at 3W and the received power is about 136mW, so there's no need for a current limiting resistor. Best tip to reduce electricity bills I have is to use less electricity, and thus your bill will be lower :P

  • Hey if you're still having trouble getting this working, I wanted to let you know that I finally had time to write a tutorial that walks through how to build it in more detail.


  • I don't see why not, but from a practical side, if the light falls it's probably going to break the LED. The levitation driver could be modified to cut the current of the inductor until the magnets are in range again, but currently if the magnets fall, the current stays on to the inductor to try and pull the magnets up which draws a bunch of power and even with the small-ish inductor, it gets pretty hot with full current.

  • Out of the box, I've measured ~2.6mA, and the LED is most likely drawing ~1mA.

  • Providing an external 3.3V power will not damage the board.

  • You should be able to. The battery pins are broken out that you could attached a cable to. This assumes your load is less than the charge current, which can be less than your set current value if the charger IC is hot.

  • If you're using an LM358 (pinout here), like used in the schematic, the input pins are 2 and 3 and the output pin is 1. so you should connect the positive end of the multimeter to pin 1 not 6. pin 6 is the inverting input of the second op-amp.

  • I think the inductor might be wired backwards. The way the circuit works, is when the magnet is too far away, the op-amp's output should go high (12V) to allow current to flow through the inductor and generate a magnetic field to pull it up closer to the sensor. When it's gets too close, the op-amp's output should go low (0V) and let gravity pull it farther away from the sensor.

    The first tip I would give is to disconnect the inductor from the circuit, and make sure the circuit is working correctly by measuring the output voltage of the op-amp with a multimeter. Without a magnet near the sensor, make sure the output voltage of the op-amp is reading close to 12V. If it's reading 0V, you should be able to adjust the potentiometer until it does. Next bring the magnet up to sensor and see if the op-amp's output voltage changes to 0V. If it doesn't change you might need to flip the magnet over so the other magnetic pole is facing the sensor, or adjust the potentiometer a bit more.

    Once you see the output change, you'll want to adjust the potentiometer until the op-amp starts to switch between high and low when the magnet is around 2cm (3/4in) from the sensor. Once you have that dialed in make sure you keep track of which side of the magnet is facing the sensor. When you connect the inductor again, you should feel the magnet being attracted to the inductor and vibrate a little as you bring that top side of the levitation distance you set earlier. If it feels like the two magnetic field are repelling each other, or the side of the magnet that was facing the sensor during the testing wants to flip over to bottom, the inductor is most likely wired backwards. Once you swap the wires it should fix it.

    Once you can feel it trying to levitate, that's when you've reached my point of frustration. It takes a bunch of patience to keep it in that sweet spot as you slowly let go and it levitates on it's own.

  • The red lead is the signal, the black lead is ground, which should be connected to the rest of your ground signals. The signal coming out of the function generator should be 5V peak-to-peak, with a 2.5V offset. So the high voltage should be 5V and the low signal should be at 0V. The function generator doesn't output very much current. the mosfet connected to the function generator is switching the current from the power supply on and off at the same rate as the frequency from the function generator. So the current you're monitoring is from the 12V power supply. Current measurement can be done by the power supply if it has the capability like this one or you can put a multimeter in series between the power supply and the circuit as shown in this guide.

    All of the 12V power can be supplied by the same power supply, and all of the 5V power can be connected by the same 5V supply.

    The hall effect sensor should be attached at the bottom of the levitation coil in the center so that it can detect the distance of the magnet from the coil. I used electrical tape to hold it place, with the flat side of the sensor facing the coil.

  • I made this a couple years ago, so my memory is a bit faded, but I just manually swept through the frequencies and kept an eye on the power supply's current draw. You'll know you're getting close to resonance as the current draw starts to increase, and as you pass resonance your current will decline.

    The note about C1 being close to IC1 is just for best practice. The capacitor is to filter out any noise on the power supply. The longer the wire is between the decoupling capacitor and the IC you're trying to filter the noise from, there will be more parasitic inductance which can introduce noise back into the supply rail. If it's on a breadboard, you just want the capacitor closer to the op-amp than to the power input connections.

    I'm not sure what you mean by procedure for connecting the power supply, but if you're using a single 12V supply, you can connect a 5V regulator to drop the voltage down from 12V to 5V to create the second power rail, or if using two power supplies, just connect 12V from one supply to the 12V rail, and 5V from the other supply to the 5V rail. With either solution, make sure you tie both grounds together.

    The 5V rail uses very little current (probably a couple mA at most), the 12V supply needs to be pretty beefy. I think the supply I used was rated for 5A, but I levitator probably uses around 1A, and the wireless power transfer uses around 2A.

No public wish lists :(