The "What's a Watt" bicycle generator gets it's first public outing at Pann Mill in High Wycombe.
Bicycle Trainer is the Oeko Trainer: www.oekotrainer.de
Pann Mill website: http://www.pannmill.org.uk/
Bicycle Trainer is the Oeko Trainer: www.oekotrainer.de
Pann Mill website: http://www.pannmill.org.uk/
Wow that was very interesting Julian, thanks for sharing, I'd be lucky to get bulb 4! lol
Was fun to see…
Can you give a link for that motor? Thanks
I was involved with a pedal powered sound system , that used Ford escort alternators , for a number of Druid events . Luckily the sound system was energy efficient , built by a BBC engineer , but it still involved feel like several hours of pedaling up a long hill ( we often spent up to 1/2 an hour pedaling to charge party flat batteries , before the first performer arrived ) & being very hacked off if people wanted to a big base line on things .
Julian, A while back on this project (can't find the actual video now) you had a question as to why why your Arduino project is limited to displaying +/-32 or 0-64.
All integer maths is done in 16 bits on your Arduino (word size of machine), unless you specify some other data type (e.g. you found forcing float fixed the problem). When the expression is calculated the multiply on the left happens first, but is limited to a 16 bits because this is what the compiler deduces as the default type in use. The largest number in 16 bits is 65535, which then raps back round to zero. 65535 / 99 = 661.969, so the largest number you can have as a result of your A/D conversion without problem is 661. After this the multiply will overflow and wrap back round to zero. For example 662×99=65538 but this is too big for 16 bits so the 17th bit get lost and is wraps back round past 0 to 2 (65538-65536=2).
As you know, the top bit is the sign bit, so actually any value over half of this, i.e. 330, gives an incorrect result because it forces the sign bit on in the result of the multiply when it shouldn't be. Note that WORD() is actually forcing the multiply to have an unsigned result, which is why you get 0-63 in this case instead of +/-32. But the problem is the same – the multiply result is limited to 16 bits.
Now you need to consider what happens when you divide the range of values that can be returned by the multiply, either +32767/-32768 (in the case of a signed result) or 0-65535 (in the case of unsigned), by 1023. Well that is either +31/-32 or 0-63.
The best way to fix your problem is to make the multiply use long (or better yet probably unsigned long since we will assume an A/D result can never be negative). Something like:
long(analogRead(A0)) x long(99) / 1023.0
It is always best on a low end microprocessor to use integer math wherever possible, because floating point calculations are expensive. As you aren't using any digits of the float result on the display, you would be even better to stick with integer maths entirely here and not use any floats at all. It will be faster and use less RAM (no need for floating point library). So:
long(analogRead(A0)) x long(99) / 1023
So, if you require a value in watts, but with 3 decimal places, it is sometimes better to calculate in mW and simply imply the decimal so the values can remain an integer. Then do integer divide and mod by 1000 to get the part to display before and after the decimal.
HTH Stuart.
This would certainly make for a potential product to get on the market, as I'm sure there's nothing like it, at least not that I could find. Sure, generating <0.2kWh for an hour of exercise will have a negligible effect on the electric bill, but the novelty of being able to see energy being put to use may encourage some to exercise just to see what they can power or sustain.
This sure beats the calorie meters on most equipment which are a rough guess at best. For example, on my rowing machine the calorie meter clocks up at the same speed whether it's on the minimum or maximum resistance setting. It's the same for several other fitness machines I checked elsewhere.
At least with a generator, the load's energy consumption will be at least the effort the user is putting out, so if the user is powering a 100 watt bulb at full brightness from a generator, the user is putting out at least that, plus some extra effort to compensate for efficiency losses caused by friction, generator efficiency, diodes, etc.
Hi Julian, great work, is it possible for you to share the code, thanks, shailesh\
it's pointless to parallel diodes, due to minute differences only one will do all the work
there seemed(to me anyway) to be a loss of energy in peoples peddling speed… was the gearing on the bike optimised for the output?
Brilliant video! good to see a project all the way through!
This is good for people that build electric bicycles to see how much power they can generate.
I think an athlete can peak at around 300W for a few seconds but it will not be able to sustain that for long. That is why legislation for electric bicycles range from 200 to no more than 300W depending on country.
Even a 200W motor on an electric bicycle will be way better that an average human and that is because it can sustain that based on battery size for up to a few hours.
An average human consume around 2000kcal worth of food/day and just a portion of that is used another part is eliminated 🙂 and maybe some is stored as fat.
Those 2000kcal are equivalent with around 2300Wh but most of that is used for buddy functions most to keep the body at around 37C and even just the brain uses around 20W that is alone 20W x 24h = 480Wh so not that much is left for the electric bicycle 🙂 a few hundred Wh/day will most likely replace a fit human on hard daily physical activity. That is just a few cents worth of electricity/day so machines can do physical work way cheaper than any human.
I wait for AI to get to the same level of efficiency and then we will be completely obsolete 🙂
That waterwheel. How old do you think those metal cogs are? I honestly have no clue myself but anything over 125 years old would blow my minds. I just can't seem to grasp how they would have made them pre 1900's. I just saw where it had the roman numerals MMX which is 2010 I wonder why.
Adding an mppt charge controller would automatically match the 80 volts DC of the generator, to the 12-14 volts of the battery. The bike would probably be easier to pedal due to the better match…
Is there sun in Britain?
Why not a ten speed?
The bike part with the generator seems to be called "ökotrainer".
Really interesting video, so you can now charge your batteries on those dull overcast British days! lol wasn't horse power calculated on pit ponies? during the mining days! I read somewhere that a working horse is around 2.2HP, not sure how true this is! Keep them coming =)
LOL! I like the Ökotrainer Carrera set, that allows you to control slot cars by pedaling. Or the cinema set where you get 8 of them to drive a projector and audio amp in a group.
Btw. do you have a comparison how accurate the reading is? I tried a few different ergometers once in a while and sustained 150W didn't seem hard to do at all even for longer times. But on your machine it seems hard to reach.