Myles Posted July 3, 2003 Share Posted July 3, 2003 I'm going to rig up a simple speed datalog system to my de-dion car. This will consist of the Polar S710 datalogging heart rate monitor (incorporates a cycle computer). Unfortunately the S710 is a wireless design - so I'm planning to mount the magnet and (chunky) speed sensor on the rear wheel/de-dion tube. The speed sensors cost about 25-30 quid - so I don't want to lose it halfway down the road (a link to a piccy here) Will it be safe just to 5-minute epoxy the sensor to the tube or should I take a different route (almost impossible to tie-wrap)? I've not had any problems with the front wheel magnet... REgds, Myles Link to comment Share on other sites More sharing options...
Harry Flatters 2 Posted July 3, 2003 Share Posted July 3, 2003 What is the sensor going to measure, attached to the DD tube? Link to comment Share on other sites More sharing options...
Myles Posted July 3, 2003 Author Share Posted July 3, 2003 FODITP, The sensor casing is about 6cms long and has an angled base. If I mount it at the very end of the tube where the rear hubs attach, it will just reach nicely to the inside lip of the rear rim - on which a magnet will be attached. Hope this helps... REgds, Myles Link to comment Share on other sites More sharing options...
Mr Locust Posted July 3, 2003 Share Posted July 3, 2003 So is it going to measure wheelspin when compared to a front wheel reading ......or is it just to get it out of sight Link to comment Share on other sites More sharing options...
Harry Flatters 2 Posted July 3, 2003 Share Posted July 3, 2003 Try this lot here. Link to comment Share on other sites More sharing options...
Myles Posted July 3, 2003 Author Share Posted July 3, 2003 I thought it prudent to keep it out of sight - not that it would prove much without downloading the data to the PC. I'd be interested to see how much wheelspin I get anyway - I'm trying to look after my CR500s after all... I also thought that it might be easier to mount the wrist unit somewhere at the rear of the car (roll bar perhaps) - whereas the only place I could think of at the front would be onto the wishbones or inside the nose somewhere (bit tricky to get to and possibly too harsh an environment.) Regds, Myles Link to comment Share on other sites More sharing options...
Myles Posted July 3, 2003 Author Share Posted July 3, 2003 FODITP, Thanks - looks interesting. Regds, Myles Link to comment Share on other sites More sharing options...
Chelspeed Posted July 3, 2003 Share Posted July 3, 2003 Are you sticking it to bare metal or to the powder coating? If it's more than a couple of years old the powder coating was so sh*te that it wouldn't matter how well you stick it to the powdercoating, a big sheet of the powdercoating will peel off and your sensor will go with it.... Better recently. Link to comment Share on other sites More sharing options...
Myles Posted July 3, 2003 Author Share Posted July 3, 2003 Powder coating. It looks fine - the car's only 2 years and 5k old. The alternative is onto the bare metal on the rear of the calipers/hubs (i.e. inside the wheel rim). Bit worried about heat though (having said that, the de-dion alternative won't be much cooler. REgds, Myles Link to comment Share on other sites More sharing options...
DohNut Posted July 3, 2003 Share Posted July 3, 2003 Where are you going to place the *screen* for this set-up? Presumably the memory facility is in this part of the kit - not the transmitter. My point being that I have dificulty getting a direct signal from a VDO wireless bike computer to the handlbars of a mountian bike, so I would expect that the screen would need to be in line of sight and within half a meter of the transmitter (German telecoms regulations) You may get away with putting it on the boot floor if it can transmit reliably through the alloy sheet - if not you will be forced to mount it under the car Nick Link to comment Share on other sites More sharing options...
Mr Locust Posted July 3, 2003 Share Posted July 3, 2003 I would have thought a light bracket + tie wraps was superior due to the vibration/powder coat waxiness etc. Link to comment Share on other sites More sharing options...
Myles Posted July 4, 2003 Author Share Posted July 4, 2003 Doh!nut, Yep - I've no intention of reading the screen whilst driving - as the Glos crowd will attest, I've got four (count them!) speed displays already (Road Angel, GPS, Sigma BC1200, std. speedo). The unit datalogs happily and just dumps the data via IR to a PC. I plan to mount it probably on the RHS rollbar - so it will be only 50cms or so from the sender (which has the facility to up the range to about '1.5m' via PC-style jumpers) and should be in LOS through the fibreglass. Or I could mount it (bit risky) on the wheel intrusion bar (ok, very risky). Mr Locust Tie wraps might be a bit of a problem due to orientation of the sender (it is designed to fit to a bike fork after all - methinks I'll reprofile it though)- I'd thought about using these as well as epoxy, but it'll need some work. Thanks for suggestions, Regds, Myles Link to comment Share on other sites More sharing options...
John Hughes Posted July 4, 2003 Share Posted July 4, 2003 Myles Check the signal will be picked up through the ali. These type of speedo's can be a pig to get to work even with clear line of sight and only just over a foot of seperation on a bike ☹️. Good luck John Link to comment Share on other sites More sharing options...
Myles Posted July 4, 2003 Author Share Posted July 4, 2003 John, That's why I was planning to mount it on the RH roll bar mount - it should only need to 'see' through the rear wing rather than any ali. I can't really see how to test it non-destructively unless I gaffer tape the sensor in place and drive very gently before commiting to glue. Well, if it works, I'll post piccies etc. Regds, Myles Link to comment Share on other sites More sharing options...
murph7355 Posted July 4, 2003 Share Posted July 4, 2003 Not wishing to put a damper on your plans, but I'm not convinced you'll get this to work effectively for many of the reasons stated above. Also, you'll only be able to monitor your speed over time in 5 second intervals (or longer)...which is probably not granular enough to extrapolate anything from it (not tried cutting and pasting out of the Polar software yet to know if you can even do this into Excel or someting anyway). Might be quite interesting to plot heart rate against speed in the car, but would think that you'd only use it once and get bored of the data... Whilst more expensive (160 or so) the AP22 unit from Race Technology would give you a massive amount more useful info and needs nothing sticking to bits of the car. And despite the wealth of info it gives, I suspect you'd get bored of that pretty quickly too (unless I'm the odd ball and everyone else plays with theirs religiously). Link to comment Share on other sites More sharing options...
bert Posted July 4, 2003 Share Posted July 4, 2003 Scuffnut, I believe the capture rate is configurable but I'm fairly sure you're right about the line of sight (site!). I had massive problems with mine trying to get a signal from slightly further than the fork on the crank on my bike. In the end, a minor adjustment of only 5mm made it start working... Link to comment Share on other sites More sharing options...
murph7355 Posted July 4, 2003 Share Posted July 4, 2003 I'm pretty sure the lowest level of granularity you can get is every 5secs. I'll have a check tonight. Had the same experience as you with getting the bike part to work. Needs very careful alignment. I would guess that the 7 will be too rough an environment to guarantee this remains... Also had a bugger of a job getting the IR connection to work. But now that it does, am finding it a really useful bit of kit. Link to comment Share on other sites More sharing options...
Myles Posted July 4, 2003 Author Share Posted July 4, 2003 The min granularity *is* 5 secs for sure - I've had mine for almost a year and a half. Even this is not great on a bicycle for capturing max-speeds. The response rate is pretty poor too - my dedicated bike comps record accelerations and decelerations much 'spritelier' I've not had problems with the speed sensor - even when mounted on a full suspension MTB - the cadence sensor is a completely different kettle of fish - even though this is basically the same piece of kit. I'm not deluding myself about the usefulness of the data - after all, I rarely delve into the details of my bike rides unless there is a high-speed descent of interest. I just think it might be fun - it should only cost me a max of about 25-30 quid after all. You definitely *can* export to excel - well, to a comma or tab delimited text file. I thought about writing some macros to automatically smooth out the speed glitches you get - but couldn't be bothered! It'll be at least a week before I get to give this a go, but I'll post progress (or lack thereof!) REgds, Myles Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now