Taxi Fare Meter

[pkvasan]

Hi

I am planning to design Taxi Fare Meter using PIC microcontroller
Input is from Speed Sensor & the meter will have 7 segment displays showing Fare & Distance in Km.
While in running the meter should show fare & distance and while the taxi is in stationary position the display should indicate Fare & time.

Please suggest me a suitable microcontroller from PIC Family which can drive
8 7Segment displays

Rgds

 

[blueroomelectronics]

None directly unless you want LCD displays then the 16F917 can drive LCD glass. Else modify the dragonfly schematic and add two more digits.
**broken link removed**

 

[SMUGangsta]

I dont know what the law is in Bangalore, but using a Taximeter that has not met the required standards in the UK is a very serious offence.

I have designed a few taximeters now, and I could save myself an absolute fortune by building my own (I fit taximeters as my job) but the cost of meeting the regulations (including sending several away to be tested (to destruction in some cases) at your own expense) and the latest european EMI regulations for vehicle electronics now in force - it is totally pointless, the red tape would bankrupt me - so I just buy them from the worlds largest manufacturer of taximeters. (On a side note, in most of the world the meter must include tamper seals, which must be integral to the casing of the meter too - which means a custom enclosure too)

Unless this is a school project, or a one-off just to prove you can do it - then dont bother - invest your time elsewhere and buy a meter off eBay (or i'll sell you one if you want!)

EDIT: As Bill stated above, none of the pics interface directly with 7Seg LED displays, but the MAX7219 or mabey one of there newer ones will drive your displays (including the hired, stopped, for hire - leds, if your clever with your layout) the MAX7219 will use just 3pins on whichever pic you choose

 

[pkvasan]

Thanks SMUGangsta for your reply

This is one-off project to try out and make maxium tamperproof. I have these meters are easily tamperable. Each time these fare meters shows different fare/kms for the same distance. so i feel there is some scope to make it further more tamperproof.

Regards.

 

[SMUGangsta]

or perhaps they just need calibrated - just out of curiosity - what meters do you have there?

 

[pkvasan]

More then calibration they also tamper it by various methods. Here in Bangalore Taxi Fare meters are made by some local manufacturers. If you wanted manufacturer’s name, no problem i will find out for you.

 

[shokjok]

Tamper-proof hardware is easier than a label. Security Torx bits are the best. It is time wasted if you attempt to drill a center hole in a small Torx bit without breaking the drillbit or Torx driver.

 

[SMUGangsta]

Tamper-proof hardware is easier than a label. Security Torx bits are the best. It is time wasted if you attempt to drill a center hole in a small Torx bit without breaking the drillbit or Torx driver.

What do you mean by a label?

The meters we use here have a bolt that runs
FRONT OF CASE>MAINBOARD>REAR OF CASE>MOUNTING BRACKET

Its a simple straight head machine screw (M4) that has been cross drilled through the head.

We feed a stainless steel wire through the head of the screw, then through a mounting on the case, and seal the ends together with a lead seal (like the electricity company seals meters with) - the seal is issued by the local athority and has my unique company number embedded in it.

The other type we use has three seperate seals, one for the case, one for the calibration, and one for the tariff. These are three little panels that have a screw behind them. Once the meter is set, we insert a unique ID/colour seal over the screwhole, which expands out into a recess in the screwhole. These are easily removed - but pretty near impossible to remove without damaging the seal. In general the seal is destroyed by the time you get to the screwhead.

In some areas having ANY damage to a seal must be reported, and an operating taxi found with a damaged seal can loose its licence and its operator liable for prosecution.

 

[on1aag]

Security Torx bits are the best. It is time
wasted if you attempt to drill a center hole in a small Torx bit without breaking the drillbit or Torx driver.

I agree, you can buy these sets everywhere.

on1aag