Generate Electricity from your Gym Workout with this Circuit

The article explains the circuit implementation of an interesting concept of converting physical energy into electricity. Here we learn a simple method of converting or channelizing the wasted gym workout energy into useful electrical energy. The idea was requested by one of the keen members of this blog, let's know more:

The Circuit Request:


Hello sir,
I'm final year ECE student.

I'm willing to generate power to my college gym.

I have some idea related to that. so I need your some idea relate to that.

How can i make power through the weight related exercise machine? we can't use piezo electric crystal.

I need some idea. and one more thing I'll tell my procedure for that if any mistake arise correct me. 

1.Generate AC power through generator
2.Gives to the rectifier
3.Save power in battery
4.Use inverter for commercial use.

The Circuit Design

Implementing the above concept is actually very straightforward as the input energy source is definite and consistent.

While working out in a gym, the participants are much eager to donate their physical power either to shed-of extra weight or for enhancing muscle growth. Therefore, anyway this power is meant for wasting which makes the concept much easier to achieve.

We all know that the most simplest way of converting a mechanical force into electricity is through a motor, or by using the force for spinning the motor and acquiring electricity from the output wires of the motor.

The above principle can be every effectively employed here as well.

All the weight training equipment in a gym which incorporate pulley/rope and suspended weight mechanism can be transformed into  electricity generating machines.

As shown in the figure below, an arrangement may be fabricated where with an additional rope pulley mechanism a simple permanent magnet type motor can be integrated with the existing weight training machine.

When any member pulls and uses the machine while working out, the motor also gets rotated in accordance, in a push pull manner.

The above movement induces the required electromotive energy across the motor output wires which is appropriately processed inside the rectifier/controller circuit and finally delivered across the connected battery for charging it.

Another point may be witnessed here, with a discharged battery connected, the motor would be subjected to greater torque making the mechanism stiffer.

This would hopefully make the whole thing more challenging and enjoyable for our "body builders".

The motor pulley should be much smaller in size compared to the machine pulley, so that the rotation ratio favors maximum number of rotations over the motor pulley and helps to generate optimal power from the motor.


A simple charger/controller is shown below, which can be employed for this application too. The circuit utilizes the well known IC LM338.

The "push-pull" voltage from the motor, or the alternating voltage from the motor is first rectified by the four diodes, filtered by the capacitor and regulated to the desired battery voltage by the IC LM338 circuit.




10 thoughts on “Generate Electricity from your Gym Workout with this Circuit

  1. Have questions? Please feel free to post them through comments! Comments will be moderated and solved ASAP.
  2. Sir,
    Good day.please is it possible to homemade a multilevel inverter.I read the waveform is much closer to sinewave than the conventional modified sinewave inverter.Thanks,Chunyelu from Nigeria.

  3. Good day Sir/Ma
    i am final year student of a technical school in Nigeria studying electronics engineering..i am commit to build a 1500watts inverter and i have being trying my best to construct it wit so many circuit diagram printed from some other websites but all seems in vain,and wasting my time,effort,resources,money and lot more..if i can see favor in sight of homemade should please paste or send me d circuit diagram for 1500watts inverter,cos i want to construct it myself bt nw wit ur help please!!

    • Good Day,

      What is the voltage source 12V or 24V…with a 12V source you would require a 150 ampere transformer, it would be very huge.

      Required battery would be 200 ah to 300 ah

  4. sir can i Generate Electricity from moving electric bike by placing front wheel BLDC HUB motor again to charge 48v battery is it possible means i need charger circuit

    • You mean use a battery to operate the bike and use a motor on the front wheel to fill up the battery simultaneously such that the battery never gets exhausted??? No, that can never be feasible….

    • Incorrect, ships from the late 1940's to 1970's + used 3 phase transmitter/receiver Ccts to control steering gear attached to the rudder(s). Call it primate power steering. A you tube video circa. 2008, showed a bicycle with identical 3 phase BLDC motors on both rims (wired in series together). ,When the front tire was turned manually, the rear rim moved at exactly the same speed and distance as the front. This worked forward or backwards – the driven rim mirrored the movement of the driving rim's speed and distance precisely. Taking this one step farther, with the proper rectifying – control cctry and an ultracapacitor bank, extended distanced can be achieved. Case in point, Zero Motorcycles, uses all wasted power during city travel so that when throttle is in off position during coasting, BLDC motor's regenerative voltage is used to charge U-bank. This was tested here in London, Ontario Canada last year. Their claim of 171miles (274 kms) per charge with 2 battery packs, under tests, gave a 200 km range under standard city riding conditions for a single charge. This is still impressive considering the battery pack voltage is only approx. 108 volts.
      I am currently retrofitting my electric scooter with a front hub BLDC motor / U-bank system to make my daily charges unnecessary.
      I have researched this for almost 1 year since I bought the scooter. I know this regenerative joule thief system will work because even with my basic regenerative braking system engaged, as long as I am travelling faster than 10 kms per hour, my voltage meter shows me a voltage 3 – 5 volts higher than my battery pack voltage.

    • Thanks for this interesting information, I'll investigate this in detail and update the results soon…..if possible I would request you to throw some more light on the concept, we all will appreciate it.

    • yes it's possible by replacing the weights by a heavy duty motor through pulley or gears.

      The motor output could be loaded with fully discharged 100ah lead acid battery

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