Automobile Instrument Cluster
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Posts: 46,084
If anyone is working on a digital Automobile Instrument Cluster then here you go.
I am a newbe at programming, so when I got the Basic Stamp 2 I needed something to help me learn how to program. My car's dash was not working when I got it. So that was to be my project, and what A project it has been. Allot of spent hours, and money. I decided to use the stock displays. There 2 displays the first display is the speed/odometer display(display1) and the other display is the bar graph tachometer display(display2). my fuel,oil,temp,& volt gauges are analog, so I· am going to keep them the same.
I started by finding out how to make the displays to work. With vacuum florescent(VF) displays there are three elements. The heater/cathode, the grid, and the anode. each one has a cretin job to do. The heater heats the display and it is the cathode of the display. what that means is there must be a negative potential on the heater. The heater must have a input voltage of 5V. Now the stamp can not supply the heater with enough current to power it. and A 1 amp 5 volt regulator will work but you must add a heat sink to it will heat up. The grid is the fine wire mesh over the segments. this directs the electrons to each segments. the grid must have a +12 - +50 volt potential. now the main thing of the displays, the anode. The anode·are the segments of the displays. the segments have a florescent phosphor on them, and when hit with electrons it lights up. the anodes must have a +12 - +50 volt potential on them.
For the display drivers I went with drivers from Allegro. these drivers are nice, they take a serial input then when you pulse the strobe pin the driver lights up the corresponding segment. I was able to hook up 7 drivers to the same 2 data, and clock pins on the stamp, and used·individual strobe (load) pins. Now I did not use 7 pins to load each driver I only used 4 load pins. that is 6 pins to drive 121 segments.
For the speed, it took me many hours to find out how to do this. I found out that the stock speed sender sends out a cretin number of pulses per revolution of the speedometer cable. so knowing this I came up with formula. ( N = number of pulse in one second)
N(pulse/sec) x 60 (sec/min) x 60 (min/hr)
but I found out that did not work. Then I found out that I need to add pulses per mile (M).
N(pulse/sec) x 60 (sec/min) x 60 (min/hr) / M(pulse/mile)
witch you can make the formula a little smaller
N x 3600 / M = mile per hour
now since the N can = 1000 and M can = 20000 the stamp can not do the math. that is where I turned to the forum, there Al told me this formula will work
N x 36 / (M / 100) = mile per hour
and it did.
Now how do I find out how what M is. for that I added a set button so I can set the pulse per mile(PPM). with the car off I would press and hold the set button then turn on the car. The stamp would see that the set button is pushed then goto a set program. there it would just count the number of pulses in one sec. I would drive the car to 60 Mph (thanks to my dad). then push the set button. what happens is the stamp counts the pulses then x60 then writes the value to the EEPROM. now you might be saying "why 60 Mph?". Well at 60Mph that is the same thing as 1 mile per minute. And that is what I need, the pulses per mile.
for the odometer I took the pulses that the stamp counted then save it then add the next pulses that it counted to it. It would keep doing this until it counted the number of PPM then it would add 1 to the odometer. now if you wanted to know down to a 1/10 of a mile just take PPM / 10.
for the tach this is how I did it. Take the count command for one sec the put it in this formula
P x (Cyl / 2) = RPM
P = pulses per sec
Cyl = number of cylinders (4,6,8 it might work with 2,10 and 12 cylinders)
·Right know I am working on adding a trip and to convert Mph to Km/h.
I wrote this for anyone trying to make a digital dash for there car. I spent many hours looking on the internet and looking for answers to my questions, with not much luck. So fill free to use this info for how you see fit. And if anyone has any questions, please I-mail me and I will give it my best shot.
Thanks to all that have gave me knowledge to do this and to spend there time to help me.
TC
I am a newbe at programming, so when I got the Basic Stamp 2 I needed something to help me learn how to program. My car's dash was not working when I got it. So that was to be my project, and what A project it has been. Allot of spent hours, and money. I decided to use the stock displays. There 2 displays the first display is the speed/odometer display(display1) and the other display is the bar graph tachometer display(display2). my fuel,oil,temp,& volt gauges are analog, so I· am going to keep them the same.
I started by finding out how to make the displays to work. With vacuum florescent(VF) displays there are three elements. The heater/cathode, the grid, and the anode. each one has a cretin job to do. The heater heats the display and it is the cathode of the display. what that means is there must be a negative potential on the heater. The heater must have a input voltage of 5V. Now the stamp can not supply the heater with enough current to power it. and A 1 amp 5 volt regulator will work but you must add a heat sink to it will heat up. The grid is the fine wire mesh over the segments. this directs the electrons to each segments. the grid must have a +12 - +50 volt potential. now the main thing of the displays, the anode. The anode·are the segments of the displays. the segments have a florescent phosphor on them, and when hit with electrons it lights up. the anodes must have a +12 - +50 volt potential on them.
For the display drivers I went with drivers from Allegro. these drivers are nice, they take a serial input then when you pulse the strobe pin the driver lights up the corresponding segment. I was able to hook up 7 drivers to the same 2 data, and clock pins on the stamp, and used·individual strobe (load) pins. Now I did not use 7 pins to load each driver I only used 4 load pins. that is 6 pins to drive 121 segments.
For the speed, it took me many hours to find out how to do this. I found out that the stock speed sender sends out a cretin number of pulses per revolution of the speedometer cable. so knowing this I came up with formula. ( N = number of pulse in one second)
N(pulse/sec) x 60 (sec/min) x 60 (min/hr)
but I found out that did not work. Then I found out that I need to add pulses per mile (M).
N(pulse/sec) x 60 (sec/min) x 60 (min/hr) / M(pulse/mile)
witch you can make the formula a little smaller
N x 3600 / M = mile per hour
now since the N can = 1000 and M can = 20000 the stamp can not do the math. that is where I turned to the forum, there Al told me this formula will work
N x 36 / (M / 100) = mile per hour
and it did.
Now how do I find out how what M is. for that I added a set button so I can set the pulse per mile(PPM). with the car off I would press and hold the set button then turn on the car. The stamp would see that the set button is pushed then goto a set program. there it would just count the number of pulses in one sec. I would drive the car to 60 Mph (thanks to my dad). then push the set button. what happens is the stamp counts the pulses then x60 then writes the value to the EEPROM. now you might be saying "why 60 Mph?". Well at 60Mph that is the same thing as 1 mile per minute. And that is what I need, the pulses per mile.
for the odometer I took the pulses that the stamp counted then save it then add the next pulses that it counted to it. It would keep doing this until it counted the number of PPM then it would add 1 to the odometer. now if you wanted to know down to a 1/10 of a mile just take PPM / 10.
for the tach this is how I did it. Take the count command for one sec the put it in this formula
P x (Cyl / 2) = RPM
P = pulses per sec
Cyl = number of cylinders (4,6,8 it might work with 2,10 and 12 cylinders)
·Right know I am working on adding a trip and to convert Mph to Km/h.
I wrote this for anyone trying to make a digital dash for there car. I spent many hours looking on the internet and looking for answers to my questions, with not much luck. So fill free to use this info for how you see fit. And if anyone has any questions, please I-mail me and I will give it my best shot.
Thanks to all that have gave me knowledge to do this and to spend there time to help me.
TC
Comments
website....
sent. and I sent this for anyone looking for answers.
--- In basicstamps@y..., Patty Gehring <gehring.2@w...> wrote:
> If you are going to send things this long, you may as well get a
> website....
>> Why should I get A website when this is the only long write up I have
>> sent. and I sent this for anyone looking for answers.
Because not EVERYONE on this list will be busy right now building automobile
instrument clusters...the information is certainly of interest, but there is
a special section in the BasicStamps group for file upload, then interested
parties may choose to download (or not).
Bear in mind that some people in the list may still be using a slow internet
connection - I for one usually read my email while on the move, via a PCMCIA
GSM modem, which only allows me 9600bps, so I certainly wouln't appreciate
emails like this...
It is common 'netiquette' NOT to post messages containing ANY sort of binary
files - imagine your 331kB post, converted to MIME runs up to around 600kB -
multiplied by, say, 1000 subscribers to a mailing list, that's 600 MEGABYTES
of data you have just sent flowing through the already congested internet...
All the best, and please keep posting useful info, but for large files, post
links to them.
Mike
Mensaje original
De: aconti@n... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=n5Xx1tRNqW9rbyDPnV5SHXqhkVvHDUryM6tfQAHKuWArIHqGAwHxr0r-gmyyUYSY2heOuz5QxoW3ig]aconti@n...[/url
Enviado el: sabado, 12 de mayo de 2001 23:36
Para: basicstamps@yahoogroups.com
Asunto: [noparse][[/noparse]basicstamps] Re: Automobile Instrument Cluster
Why should I get A website when this is the only long write up I have
sent. and I sent this for anyone looking for answers.
--- In basicstamps@y..., Patty Gehring <gehring.2@w...> wrote:
> If you are going to send things this long, you may as well get a
> website....
Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
> If anyone is working on a digital Automobile Instrument Cluster
then here you go.
Thank you.
I'm getting an '89 VW Cabriolet this week, and I was toying with the
idea of replacing the lower instrument cluster (oil pressure, oil
temp, and alternator output) with a digital display...
bkd