Interior How-To: Linear Water Temp Gauge
09-01-2011, 08:26 AM
#12
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Join Date: Aug 2011
Posts: 58
10-08-2011, 07:11 PM
#14
MFz Regular
Join Date: Oct 2011
Location: Charlotte
Posts: 248
Me being one of them! I dont want to break those stupid clips...
Great writeup Track! Eventually I plan to pull the cluster and do something similar to this, I want to make it with gauges that have actual numbers for peace of mind though.
Great writeup Track! Eventually I plan to pull the cluster and do something similar to this, I want to make it with gauges that have actual numbers for peace of mind though.
10-08-2011, 07:20 PM
#15
BAMFr
Thread Starter
Join Date: Jul 2011
Location: NC
Posts: 1,787
if you want a set of gauges like that, take a visit over to revlimiter's blog and either a buy a set of his pre-made gauges or make your own following his DIY.
I will be moving my LED gauge cluster+mylar how to sometime in the near future and possibly doing a how-to on the OPG linear mod and degreasing. I am hesitant to really do it at this time though as the OPG linear mod is not my work at all, its just there isn't a clear how to on it (although the degreasing is).
so if you are interested in the OPG, get some numbers on that gauge too!
I will be moving my LED gauge cluster+mylar how to sometime in the near future and possibly doing a how-to on the OPG linear mod and degreasing. I am hesitant to really do it at this time though as the OPG linear mod is not my work at all, its just there isn't a clear how to on it (although the degreasing is).
so if you are interested in the OPG, get some numbers on that gauge too!
10-30-2011, 10:41 PM
#16
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Join Date: Jul 2011
Location: Lake Jackson, TX
Posts: 13
Just thought I'd toss in some more data for consumption on this thread:
I've been playing with a spare cluster that I pulled from a '93 car and wanted to make the temp gauge linear. I followed the instructions created by Wallyman, but I came across two issues along the way.
1) My sensor seems to have a slightly different resistance/calibration curve. At 120F, my sensor has approx. 30 ohms less resistance than what is specified by Wallyman. However, the deviation in resistance gets smaller the closer it gets to 270F. I've attached a graph of the resistance curves from 120F-210F.
2) When I used the resistor values that he suggested, my gauge was skewed such that the range was approximately 1ooF @ C to 180F @ H. I ended up using a parallel value of 210-ohms and a series value of 18-ohms. This gives me a range of approximately 150F at C to an estimated 270F @ H. (I have no intention of getting my car that hot, so I can't verify exactly how accurate it is. :P )
Not sure if I've got an odd sensor AND an odd gauge, or if the calibration specs for the gauges and sensors are just very loose.
I'll try to get some video of the gauge in action later this week.
I've been playing with a spare cluster that I pulled from a '93 car and wanted to make the temp gauge linear. I followed the instructions created by Wallyman, but I came across two issues along the way.
1) My sensor seems to have a slightly different resistance/calibration curve. At 120F, my sensor has approx. 30 ohms less resistance than what is specified by Wallyman. However, the deviation in resistance gets smaller the closer it gets to 270F. I've attached a graph of the resistance curves from 120F-210F.
2) When I used the resistor values that he suggested, my gauge was skewed such that the range was approximately 1ooF @ C to 180F @ H. I ended up using a parallel value of 210-ohms and a series value of 18-ohms. This gives me a range of approximately 150F at C to an estimated 270F @ H. (I have no intention of getting my car that hot, so I can't verify exactly how accurate it is. :P )
Not sure if I've got an odd sensor AND an odd gauge, or if the calibration specs for the gauges and sensors are just very loose.
I'll try to get some video of the gauge in action later this week.
10-31-2011, 09:54 PM
#17
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Join Date: Sep 2011
Location: Mt.Peak, Texas
Posts: 190
I have not tried this on a miata but the question I have is series or parallel. In the first post you can't do both .
Doing series circuit will make it work one way and doing a parallel circuit will affect it in a different way
Did you possibly mean a series parallel circuit whereas there is a series circuit and inside thhe circuit is a paralell circuit
Just wondering for clarification .
I may just be reading the first post wrong
Doing series circuit will make it work one way and doing a parallel circuit will affect it in a different way
Did you possibly mean a series parallel circuit whereas there is a series circuit and inside thhe circuit is a paralell circuit
Just wondering for clarification .
I may just be reading the first post wrong
Last edited by mytwo; 10-31-2011 at 09:58 PM.
10-31-2011, 10:13 PM
#18
BAMFr
Thread Starter
Join Date: Jul 2011
Location: NC
Posts: 1,787
if you are asking me...Let me explain a bit of circuitry. Series and parallel are just two different configurations to do the same thing. Following Ohms law
R=V/I
In otherwords, resistance is a ratio of voltage to current. So if you have a basic circuit were 5v is applied to a resistance of 10...you get:
I=V/R=5/10=.5A
So you have a half amp of current. Now if you have two resistors in parallel like this:
R1=R2=10
Ground is at the bottom. (sorry I am stealing this picture and too lazy to draw it in).
Now lets apply 5v to the white circle, you will get .5A down R1 and .5A down R2. Since that current has to come from somewhere you figure out that 1A is coming out of the voltage source (from white circle to black dot is 1A, .5A goes down R1 and .5 goes down R2).
Now, lets do the same thing another way, since we know 5/10 is .5A and when we put two parallel resistors together we ended up with double the current, then maybe we can do this by find an equivalent single resistor value to give us this.
So, there is two ways to go this now, you can either take the 5v and 1A and plug them into the ohms law giving you 5Ohms. Normally you won't know current (so you know when your car is running that the voltage will be 14.4v and your resistance value is given in the how-to, so current is the unknown here)...So we can use a good old formula:
Rtotal= (R1*R2)/(R1+R2)
Easy enough eh? To simplify things, parallel and series resistances are the same thing, with different values. In our case, its two different methods of coming to the same end. You need X resistance and you can get that by two formulas:
X= (R1*R2)/(R1+R2) - Parallel resistors
OR
X=R1+R2 - Series resistors
R=V/I
In otherwords, resistance is a ratio of voltage to current. So if you have a basic circuit were 5v is applied to a resistance of 10...you get:
I=V/R=5/10=.5A
So you have a half amp of current. Now if you have two resistors in parallel like this:
R1=R2=10
Ground is at the bottom. (sorry I am stealing this picture and too lazy to draw it in).
Now lets apply 5v to the white circle, you will get .5A down R1 and .5A down R2. Since that current has to come from somewhere you figure out that 1A is coming out of the voltage source (from white circle to black dot is 1A, .5A goes down R1 and .5 goes down R2).
Now, lets do the same thing another way, since we know 5/10 is .5A and when we put two parallel resistors together we ended up with double the current, then maybe we can do this by find an equivalent single resistor value to give us this.
So, there is two ways to go this now, you can either take the 5v and 1A and plug them into the ohms law giving you 5Ohms. Normally you won't know current (so you know when your car is running that the voltage will be 14.4v and your resistance value is given in the how-to, so current is the unknown here)...So we can use a good old formula:
Rtotal= (R1*R2)/(R1+R2)
Easy enough eh? To simplify things, parallel and series resistances are the same thing, with different values. In our case, its two different methods of coming to the same end. You need X resistance and you can get that by two formulas:
X= (R1*R2)/(R1+R2) - Parallel resistors
OR
X=R1+R2 - Series resistors
11-01-2011, 08:46 PM
#19
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Join Date: Sep 2011
Location: Mt.Peak, Texas
Posts: 190
Track you did good. WAith serries or parrell there is a difference with voltage two 6 volt batteries in series gives you 24 volts in parrell it is still just 12 volts jump more amperage and longer draw.
By no means am I a electroics person was just think that if you did it parallel then it would have a different voltage and amperage on the circuit than with them in series
I guess my thought was if in parallel you would have more resistence than in series or maybe that is basakwards
By no means am I a electroics person was just think that if you did it parallel then it would have a different voltage and amperage on the circuit than with them in series
I guess my thought was if in parallel you would have more resistence than in series or maybe that is basakwards
11-01-2011, 09:02 PM
#20
BAMFr
Thread Starter
Join Date: Jul 2011
Location: NC
Posts: 1,787
did you read what I wrote? Series and parallel resistance is completely different than series and parallel voltage/current sources.
parallel voltage sources provide the same voltage at node, but can have a larger capacity for amperage. technically the power output at each power source will be half (same voltage at node, half current output). This is much more difficult to demonstrate in circuit diagrams and is irrelevant here. In fact, most circuit diagrams ignore such limits. For the most part KVLs and KCLs make quite a lot of assumptions (all circuits are in 1 point in space, so distance has no effect on power for one, leakage current?, current limits?, wire resistance?, etc. etc.), but its all not required.
Lets not get off topic on boring electronics. Take it from an electrical Engineer. you can do either parallel resistance or series, depending on what strikes your fancy. just follow my two formulas for calculating overall resistance for the two resistors and you will be good to go.
If you have questions about what you figure out, post it on here and i will help. I will go so far as to offer doing this mod for free for anyone having trouble (who pays shipping and handling).
parallel voltage sources provide the same voltage at node, but can have a larger capacity for amperage. technically the power output at each power source will be half (same voltage at node, half current output). This is much more difficult to demonstrate in circuit diagrams and is irrelevant here. In fact, most circuit diagrams ignore such limits. For the most part KVLs and KCLs make quite a lot of assumptions (all circuits are in 1 point in space, so distance has no effect on power for one, leakage current?, current limits?, wire resistance?, etc. etc.), but its all not required.
Lets not get off topic on boring electronics. Take it from an electrical Engineer. you can do either parallel resistance or series, depending on what strikes your fancy. just follow my two formulas for calculating overall resistance for the two resistors and you will be good to go.
If you have questions about what you figure out, post it on here and i will help. I will go so far as to offer doing this mod for free for anyone having trouble (who pays shipping and handling).
Last edited by Track; 11-01-2011 at 09:06 PM.