Hi,
Do anyone of you know about a watt meter for bikes that can talk to an Arduino? Either through analog output, I2C or similar.
I know that it is possible to use strain gauges, but I am really looking for something more plug-and-play.
I have only spent around half an hour googling for this, but it would be very interesting to know any hand-on experience.
You are trying to measure the power delivery of the person operating the bike ?
A non motorised bike with pedals ?
erikhjertholm:
Do anyone of you know about a watt meter for bikes that can talk to an Arduino? Either through analog output, I2C or similar.
No, but you could buy a commercial bicycle power meter, monitor the communication between the sending unit and the receiver, and attempt to hack it. Would be fun exerci$e. 
Some of them, such as the US$600 PowerTap G3, use ANT+ compatible protocol, which might be Arduino readable.
6v6gt:
You are trying to measure the power delivery of the person operating the bike ?
A non motorised bike with pedals ?
Sorry for the late response, I didn't get any notification, so I didn't know I had gotten any answers. Yes, exactly. An standard exercise bike. I think it should both be possible to use the pedal-versions and the (internal shaft)? -version.
DaveEvans:
No, but you could buy a commercial bicycle power meter, monitor the communication between the sending unit and the receiver, and attempt to hack it. Would be fun exerci$e.
Yes, this is definitely an option, but they are a bit expensive, so I want to know if I will succeed first 
DaveEvans:
Some of them, such as the US$600 PowerTap G3, use ANT+ compatible protocol, which might be Arduino readable.GitHub - brodykenrick/ANTPlus_Arduino: ANT+ (Nordic nRF24AP2) UART interface for Arduino
Thank you, I will look into the ANT+ protocol.