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RichK

IVA requirements - DIY speedometer / odometer

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RichK

Whilst I'm sorting garage, starting the donor strip, I've been playing with creating my own digi dash (which will also potentially control fans/indicators/lights/horn and other 'body' functions).

Its been a fun project so far, with minimal outlay, and I'm currently testing it on a small cheap 2.8" display, ahead of buying a more expensive 5" sunlight readable display for the finished version. At the moment it's been a good way to learn to code an Arduino (it's always easier to learn this kind of things with an end project in mind), and it's been a fun project so far with practically nil outlay to date, and could potentially be a viable alternative to buying an expensive dash, at least for the initial build.

 

I am struggling however to find a definitive answer to the question of whether this is ok for IVA. The IVA inspection manual section 17 ''Speedometer and Reverse Gear' has specification for re-ability (can be read from driver's seat, suitably visible/illuminated at all times),  accuracy/tolerance requirements, and it states:

"The speedometer must be of a type suitable for M1 vehicle use. The types manufactured for bicycles, racing only, those that rely on GPS or those that require switching as a separate function to that of operating the vehicle or those that have a separate power source from the vehicle or where they do not operate as an automatic function when the vehicle is driven are not permitted. Where the device is in question the presenter may provide evidence as to the suitability of the device for road use from the manufacturer of the device"

 

I am not sure what 'Where the device is in question......' in the above paragraph means? Is this just if it cannot demonstrate road speed when the vehicle is IVA'd on the speedometer rolls?

 

I can make the dash boot immediately without delay on  key on, displaying odo and speedometer near instantly, and it will be powered off the vehicle 12v supply. I'll be able to adjust the calibration at IVA if required also.

 

I'm planning to use the usual OEM speed pickup in the (mk2) Mazda gearbox (VR sensor) to deliver road speed, and create an algorithm to store the Odometer value in an EEPROM chip on sleep/shutdown. So the odometer will display accurately and record actual mileage based on displayed road speed.

 

However, I am not 100% sure that this will be IVA compliant, as it is completely DIY. I cannot find however any rule that seems to forbid it explicitly.

Most commercially bought speedometers and odometers can be programmed to read whatever the user wishes, so in many ways this is not different, however I an not certain.

 

Does anyone have a definitive answer or experience of whether or not a DIY or user modifiable speedometer / odometer  would be acceptable for IVA & registration?

 

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Mark (smokey mow)

The only difference that makes yours a DIY speedo rather than commercially available is the quantity sold so far. Providing it does everything it should do and in the way it's required to so as to pass IVA (as you've posted above) then I see no issue with a one-off design.

 

the exclusions relating to bike speedos and GPS etc are mainly down to lack of back lighting and readability in tunnels etc. Also the dash must always display the vehicle speed whereas some of these devices allow you to switch to other screens that may not show the speed.

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Chris King - Webmaster and Joint North East AO

I think there may be a requirement for the odometer to be non editable so that the mileage can not be altered? Otherwise I can’t see why you shouldn’t be able to use your own dash. 

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Chris King - Webmaster and Joint North East AO
1 hour ago, RichK said:

Most commercially bought speedometers and odometers can be programmed to read whatever the user wishes,

Not so sure about that?

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Dave Eastwood (Gadgetman) - Club Secretary
3 hours ago, RichK said:

Most commercially bought speedometers and odometers can be programmed to read whatever the user wishes, so in many ways this is not different, however I an not certain

 

1 hour ago, Chris King - Webmaster and Joint North East AO said:

Not so sure about that?

 

Indeed.

 

Only a relatively modest proportion of aftermarket speedometers and a very small proportion of digital dashes seem to be reprogrammable on-demand*, as far as the odometer is concerned, it’s almost always by either the manufacturer or a main service agent.

 

*A greater number may be physically capable of having different mileages saved to memory, but the manufacturers have strict policies with regard to not altering the figures.

 

in theory, as long as all the main design requirements are met though, it shouldn’t really be a problem, however, if you start making the inspector nervous/concerned about any aspect, they might just ask you to provide the documentation proving it’s suitability.

 

One thing I can’t recommend highly enough though, is reaching out and speaking to the them! If you contact VOSA with a technical question about the IVA, you usually get put through to a tester to answer you, rather  than speculate what the interpretation is likely to be, just ring up and have a word. If, like me, when I had a question, you’ve already booked the test, you even usually get put through to the centre you’re booked at, so I actually ended up speaking to my tester. (A question about Westfield clamshell wings). He then subsequently recognized me and the car when the test rolled round,  and his whole approach shifted a gear immediately, putting him much more at ease with what he was testing.

 

 

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Snags

Hi, IVA completed a year ago, and I used the Sierra set up off my donor vehicle so was mechanical from the gearbox.

My tester was impressed by this and was complimentary about the accuracy. This only operated with back lighting when lights were switched on and all was confirmed ok.

The test is on a static rolling road so GPS set ups will not register and generally not allowed, he was not very complimentary about electronic units however as he found them very hit and miss so try to get it right for day.

As stated above the examiners are very helpful and are not big bad ogres, I talked to mine after the first fail to confirm what had to be corrected(not a lot 😃).

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RichK

I asked the DVSA and they have confirmed that for IVA, I will have to meet the  required standards relating to speedometers as detailed in section 17 of the inspection manual, and that there are no requirements relating to the odometer. 

 

So, I'll get started with the next stage of this little project now. 😬

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Chris King - Webmaster and Joint North East AO
Just now, RichK said:

I asked the DVSA and they have confirmed that for IVA, I will have to meet the  required standards relating to speedometers as detailed in section 17 of the inspection manual, and that there are no requirements relating to the odometer. 

 

So, I'll get started with the next stage of this little project now. 😬

Result 👍

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