Cheap and easy rev counter

[chris w]

Thanks for the info, ideal for a HA2 at 1500 RPM.

I see wireless speedo's are available.

 

http://www.maplin.co.uk/Module.aspx?Module...O&U=strat15

Try Ebay as well - there are usually some great bargains to be had, eg: click here

 

Chris

[Guest]

http://uk.youtube.com/watch?v=dSINO6MKtco

 

I assume you may be referring to ?

The very one! One of the funniest sketches ever IMHO right up there with "fork 'andles."

[Kraken]

Try Ebay as well - there are usually some great bargains to be had, eg: click here

 

Chris

 

 

Does anybody have an idea about the range of these? Would they work from the engine room to the steering position, say 14 feet?

[wonderdust]

Just tried a couple of cateye wireless ones and they don't pick up the signal more than a couple of feet away from the sensor.

[alan_fincher]

I tried it with a cycle computer I own and even though the speeds in km/hr are way above what one would expect from a bike, the internal electronics have a VAST range; mine allows circumferences from 1mm up to nearly 4000mm! and speeds up to warp levels!

 

 

The old bike speedo I used would not work at anywhere near the range of the new ones it would appear.

 

 

Modern bike computers typcally will indicate up to 199.9 km/hr which means that one can monitor revs up to 1999 rpm

 

Just an update on the "Using a cycle computer to calibrate a diesel tachometer" idea.

 

Having just installed a permanent tacho that needed calibrating we thought we would try it, and went armed with 3 different cycle computers.

 

We did not find any of the ones we had as flexible as the one Chris used, and they would not display above 99.9 kilometers per hour, so with the wheel size set to 1667 mm, were useful to calibrate only to just short of 1000 rpm.

 

However one helpfully would allow the wheel circumference to be set to just 167 mm, (one tenth of the suggestion), so the display represented RPM divided by 100, rather than RPM divided by 10.

 

In this way we were able to record revolutions up to around 1500 RPM, but although the display range of the computer would go much higher, at anything much above 1500 RPM the sensor was failing to cope with a magnet whipping past it 25 times per second, and the treading became erratic.

 

Still, I reckon we got it pretty good, and certainly accurate enough for all practical purposes.

 

Encouragingly it is recording the engine as idling somewhere between 650 and 700 RPM, which is a perfect match with what the operation manual says it should be.

 

I would suggest this technique probably works best with older slower revving engines, and, almost certainly with cycle computers a bit more modern than any of the three we had, (Cateye Mity 3 / Halfords 5 function + Equuus (French)).

[Taslim]

Apparently in a follow up version he is stupid enough to try enquiring about a galvanic isolator.....

 

Nice one.

[Chalky]

Modern bike computers typcally will indicate up to 199.9 km/hr which means that one can monitor revs up to 1999 rpm

 

Chris

 

Yes, but only relevant if your name is Cavendish!