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19. Project development

The idea for my final project was developed during week 7. Unfortunately, after that week, we were under lockdown, and the entire final project was done during the last two weeks of our Fab Academy after the lockdown. I want to say that the period of my 2020 summer that I spent in Dilijan doing my final project was one of the most exciting and memorable parts of my life. Please check final project page

what tasks have been completed, and what tasks remain?

Here is the schedule showing what was completed. The green boxes indicate tasks that are done, and the red boxes indicate tasks that are not done.

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Unfortunately, due to the short time, I couldn’t work on the appearance of the scooter. Also, unfortunately, I haven’t improved the scooter since 2020.

What’s working? what’s not?

The headlight works perfectly even after 4 years it still works. In my estimation AtTiny44 is super reliable microcontroller.

The PWM driver that I got was rated for 60amps but I discovered too late that engine starters can drain 150amps at their peak that’s why my driver was fried when I went full power.

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The bycicle tyres I used were 16x1.25 and are rated for 125kg max. But somehow they didn’t last long and are damaged now need replacement.

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The batteries work fine although I wasn’t able to measnure the actual range they will last. But let’s calculate how far it could travel with 4 12v 9Amp/h batteries.

The weight of my bike is 41kg I wight 64kg so total is 105kg. 4 batteries combined produce 24v and 18Amps/h in total 432Wh of energy.

To calculate how far a 105kg bike can travel with 432Wh (watt hour) of energy, we need to make some assumptions about the efficiency of the system and the specific energy consumption of the object.

The energy consumption of electric bikes can vary widely, but a typical value is around 10-20 Wh per kilometer. We’ll use an average value of 15 Wh/km for this calculation. Calculation:

Energy available: 432 Wh
Energy consumption: 15 Wh/km

To find the distance:

Distance=Energy availableEnergy consumptionDistance=Energy consumptionEnergy available​

Distance=432 Wh15 Wh/kmDistance=15 Wh/km432 Wh​

Distance=28.8 kmDistance=28.8 km

So, with 432 watt-hours of energy, a 105 kg object (assuming an average energy consumption of 15 Wh/km) can travel approximately 28.8 kilometers.

What questions need to be resolved?

Change the motor. I bought another motor and modified the sprocket. It’s 350W 24V DC motor specificaly made for bycicles. I will add this in near future.

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Change the tyres.

Paint the bycicle. I need to dissasemble the bike paint it and assemble it back.

What have you learned?

First of all I learned Murphy’s Law which is “Anything that can go wrong will go wrong, and at the worst possible time.”

At that period of my life, this was the biggest project that I developed and made. After presenting my final project in 2020, it took me a long time to fully understand what I had learned from my Fab Academy. I realized the full value of this course after a long time (1-2 years).

  • Lesson 1: First, do research.

  • Lesson 2: There is always someone in the world who has tried to do what you are going to do. If possible, find them and ask for suggestions. (You will still make mistakes, but they will be minor.)

  • Lesson 3: Everything is possible.

  • Lesson 4: Read the FAQ.