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Home-made ranging and hold-over "computer system"

D

dtkutchu

Private
Full Member
Minuteman
Feb 16, 2010
28
0
33
Macomb, MI
Today, I took my TI83+ calculator and programmed in the formulas for range estimation as well as hold-over in mils (mil-dot scope obviously). I was initially going to buy the mil-dot master slide-rule thing, but I thought that it would take too much time to slide the thing around and try to get the lines to match up exactly, so I was hoping that this would save some time. 3 simple inputs, and out comes my range or hold-over. I was I wish the programmable calculators were a little smaller, but it should work out well.
Anyone else try this, or something similar?

edit:
New Code for mil and moa outputs

Hold:
ClrHome
Disp "V of Target(mph)"
Prompt V
Disp "V of Muzzle(fps)"
Prompt Y
Disp "Distance(yds)"
Prompt D
((V*5280)/3600)*12*((D*3)/Y)-> G
G/(.036*D)-> H
H*3.483->M
ClrHome
Disp "Hold:"
Output(2,1,"Mils"
Output(4,1,"MOA"
Output(3,1,H)
Output(5,1,M)

Range:
ClrHome
Disp "Size(in)"
Prompt I
Disp "Size(Mils)"
Prompt S
(I*27.77)/S->Y
Y*.9144->M
Disp "Range:"
Output(2,1,"Yards")
Output(4,1,"Meters")
Output(3,1,Y)
Output(5,1,M)
 
Re: Home-made ranging and hold-over "computer system"

interesting idea. I would be interested to see your programming strings.
 
Re: Home-made ranging and hold-over "computer system"

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Jig Stick</div><div class="ubbcode-body">interesting idea. I would be interested to see your programming strings. </div></div>

Hold:
ClrHome
Disp "V of Target(mph)"
Prompt V
Disp "V of Muzzle(fps)"
Prompt Y
Disp "Distance(yds)"
Prompt D
((V*5280)/3600)*12*((D*3)/Y)-> G
G/(.036*D)-> H
Disp "Hold in Mils="
Disp H

Range:
ClrHome
Disp "Size(yds)"
Prompt Y
Disp "Size(Mils)"
Prompt M
(Y*1000)/M->R
Disp "Range in Yards="
Disp R
 
Re: Home-made ranging and hold-over "computer system"

Please share the formula entered. I've got a TI83 that is not being used for anyhting now my class is over. If your formula catches on maybe I can trade it for some bullets......
 
Re: Home-made ranging and hold-over "computer system"

I should have waited another few seconds...thanks!
 
Re: Home-made ranging and hold-over "computer system"

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: sobrbiker883</div><div class="ubbcode-body">I should have waited another few seconds...thanks! </div></div>

you are welcome. If there are any other formulas that need to or can be programmed, let me know. I can write them out and test it and share them

edit: or if you need units changed, I can type that up pretty quickly as well
 
Re: Home-made ranging and hold-over "computer system"

The other thing to remember though, is that the bullet flight time ((D*3)/Y)is based on the muzzle velocity. The velocity of the bullet changes with distance to the target, as well as if there is wind coming toward you. With some physics and another input, the wind could be compensated for, but the changes in velocity over a distance would be a little bit harder for me to compensate for without the help of others
 
Re: Home-made ranging and hold-over "computer system"

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: dtkutchu</div><div class="ubbcode-body">The other thing to remember though, is that the bullet flight time ((D*3)/Y)is based on the muzzle velocity. The velocity of the bullet changes with distance to the target, as well as if there is wind coming toward you. With some physics and another input, the wind could be compensated for, but the changes in velocity over a distance would be a little bit harder for me to compensate for without the help of others </div></div>

Nice work - I'm getting my ti86 out of a box from college right now...

Have you looked at the bibliography on the JBM site? I'd imagine all of the equations you need are in those sources. http://www.jbmballistics.com/ballistics/bibliography/bibliography.shtml
 
Re: Home-made ranging and hold-over "computer system"

Might want to change the following so it prompts you for target in inches instead of yards. Not a lot of targets are a yard tall. The "Prompt I" is a upper case "i".

Also the holdover function doesn't handle 0 speed target. Div/0.

----
Range:
ClrHome
Disp "Size(in)"
Prompt I
I/36->Y
Disp "Size(Mils)"
Prompt M
(Y*1000)/M->R
Disp "Range in Yards="
Disp R
----

Would be nice to have these equations for MOA based reticles since a lot of people don't use MIL dots. Wait...here it is.
----
Range in MOA
ClrHome
Disp "Size(IN)"
Prompt I
Disp "Size(MOA)"
Prompt M
(I/M)*100->R
Disp "Range in Yards="
Disp R
----

http://www.scribd.com/doc/2468632/The-Derivation-of-the-Range-Estimation-Equations
http://static.scribd.com/docs/d2ke2aetnlp77.pdf
 
Re: Home-made ranging and hold-over "computer system"

Man...I'd love to do this..but I am retarded when it comes to my Ti-84. Any help on how to actually program this in would be greatly appreciated!

Thanks

Mat
 
Re: Home-made ranging and hold-over "computer system"

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 300snipe</div><div class="ubbcode-body">Might want to change the following so it prompts you for target in inches instead of yards. Not a lot of targets are a yard tall. The "Prompt I" is a upper case "i".

Also the holdover function doesn't handle 0 speed target. Div/0.

----
Range:
ClrHome
Disp "Size(in)"
Prompt I
I/36->Y
Disp "Size(Mils)"
Prompt M
(Y*1000)/M->R
Disp "Range in Yards="
Disp R
----

Would be nice to have these equations for MOA based reticles since a lot of people don't use MIL dots. Wait...here it is.
----
Range in MOA
ClrHome
Disp "Size(IN)"
Prompt I
Disp "Size(MOA)"
Prompt M
(I/M)*100->R
Disp "Range in Yards="
Disp R
----

http://www.scribd.com/doc/2468632/The-Derivation-of-the-Range-Estimation-Equations
http://static.scribd.com/docs/d2ke2aetnlp77.pdf
</div></div>

Yeah, I forgot to add the menu for moving target or stationary for the hold-over. I will add it tomorrow and post it up. Thanks for adding the MOA equation as well
 
Re: Home-made ranging and hold-over "computer system"

Here's the same equations in Python scripting language. You can use this in Android phones (pretty sure) and definitely Nokia N900 phones (I have one).
----
Range - works
----
#!/usr/bin/python
from __future__ import division
I = float(raw_input("Target size (inches): "))
M = float(raw_input("Target size (MOA): "))
R = (I/M) * 100
print "Range in Yards: %i"%(R)
----

Holdover - hmmmm, not working.
----
Bizarre... when I code this one as such:

#!/usr/bin/python
from __future__ import division
V = int(raw_input("Velocity of target(mph)V: "))
Y = int(raw_input("Velocity at muzzle(fps)Y: "))
D = int(raw_input("Distance to target(yds)D: "))
H = (((V*5280)/3600)*12*((D*3)/Y))/(.036*D)
print "(((%s*5280)/3600)*12*((%s*3)/%s))/(.036*%s)"%(V,D,Y,D)
print "Holdover (MILS): %f"%(H)
----
It doesn't give me the correct holdover. Let's say I use V=1, Y=2600, D=1000, I get the following:
(((1*5280)/3600)*12*((1000*3)/2600))/(.036*1000)
Holdover (MILS): 0.564103

However when I use the code from the ti83/86 program I get H=20.30769.. holdover. What is going on with the ti that's so special here? The equations are the same afaik.
 
Re: Home-made ranging and hold-over "computer system"

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 300snipe</div><div class="ubbcode-body">Here's the same equations in Python scripting language. You can use this in Android phones (pretty sure) and definitely Nokia N900 phones (I have one).
----
Range - works
----
#!/usr/bin/python
from __future__ import division
I = float(raw_input("Target size (inches): "))
M = float(raw_input("Target size (MOA): "))
R = (I/M) * 100
print "Range in Yards: %i"%(R)
----

Holdover - hmmmm, not working.
----
Bizarre... when I code this one as such:

#!/usr/bin/python
from __future__ import division
V = int(raw_input("Velocity of target(mph)V: "))
Y = int(raw_input("Velocity at muzzle(fps)Y: "))
D = int(raw_input("Distance to target(yds)D: "))
H = (((V*5280)/3600)*12*((D*3)/Y))/(.036*D)
print "(((%s*5280)/3600)*12*((%s*3)/%s))/(.036*%s)"%(V,D,Y,D)
print "Holdover (MILS): %f"%(H)
----
It doesn't give me the correct holdover. Let's say I use V=1, Y=2600, D=1000, I get the following:
(((1*5280)/3600)*12*((1000*3)/2600))/(.036*1000)
Holdover (MILS): 0.564103

However when I use the code from the ti83/86 program I get H=20.30769.. holdover. What is going on with the ti that's so special here? The equations are the same afaik. </div></div>

lol idk. I just have an enV Touch, so I can't put anything on my phone
 
Re: Home-made ranging and hold-over "computer system"

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Cybnew</div><div class="ubbcode-body">Man...I'd love to do this..but I am retarded when it comes to my Ti-84. Any help on how to actually program this in would be greatly appreciated!

Thanks

Mat </div></div>

Hit the PRGM button, then hit Edit, enter a name for the program. type in the equations as the OP posted. Hit Exit when done. Then run the program. Here's a basic howto for programming with the 83: http://www.ticalc.org/programming/columns/83plus-bas/cherny/
 
Re: Home-made ranging and hold-over "computer system"

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 300snipe</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Cybnew</div><div class="ubbcode-body">Man...I'd love to do this..but I am retarded when it comes to my Ti-84. Any help on how to actually program this in would be greatly appreciated!

Thanks

Mat </div></div>

Hit the PRGM button, then hit Edit, enter a name for the program. type in the equations as the OP posted. Hit Exit when done. Then run the program. Here's a basic howto for programming with the 83: http://www.ticalc.org/programming/columns/83plus-bas/cherny/ </div></div>

Thanks! That helped a ton!
 
Re: Home-made ranging and hold-over "computer system"

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Cybnew</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 300snipe</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Cybnew</div><div class="ubbcode-body">Man...I'd love to do this..but I am retarded when it comes to my Ti-84. Any help on how to actually program this in would be greatly appreciated!

Thanks

Mat </div></div>

Hit the PRGM button, then hit Edit, enter a name for the program. type in the equations as the OP posted. Hit Exit when done. Then run the program. Here's a basic howto for programming with the 83: http://www.ticalc.org/programming/columns/83plus-bas/cherny/ </div></div>

Thanks! That helped a ton! </div></div>

Ahhh.... got it. I was modifying a MOA holdover equation that was all wrong.

Here's the Holdover in MILs for Python

<div class="ubbcode-block"><div class="ubbcode-header">Code:</div><div class="ubbcode-body ubbcode-pre" ><pre>#!/usr/bin/python
from __future__ import division
V = float(raw_input("Velocity of target(mph)V: "))
if V < 1:
V = 1.0
Y = float(raw_input("Velocity at muzzle(fps)Y: "))
D = float(raw_input("Distance to target(yds)D: "))
H = (((V*5280)/3600)*12*((D*3)/Y))/(.036*D)
#print "(((%s*5280)/3600)*12*((%s*3)/%s))/(.036*%s)"%(V,D,Y,D)
print "Holdover (MILS): %f"%(H)</pre></div></div>

If anyone wants it in PHP, Perl, or Bash/Shell let me know and I'll code it up. If anyone wants to help with some of the more advanced equations I'd be up to making webapp code for forms and host it on my servers. Obviously we won't be competing with JBM or anything but it could be a fun project.
 
Re: Home-made ranging and hold-over "computer system"

this is awesome. we should make a post w/ all of the correct ti-83 and android formulas.
 
Re: Home-made ranging and hold-over "computer system"

This single thread is worth the cost of admission.

Great job guys.
 
Re: Home-made ranging and hold-over "computer system"

Yeah no kidding nice job guys. Now..can someone make an iphone/ipod app that does this
 
Re: Home-made ranging and hold-over "computer system"

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">can someone make an iphone/ipod app that does this.</div></div>

Umm, Ballistic FTE on the Iphone/Itouch does that kind of calculation, and so, I expect do the other ballistic programs available for it.
 
Re: Home-made ranging and hold-over "computer system"

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lindy</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">can someone make an iphone/ipod app that does this.</div></div>

Umm, Ballistic FTE on the Iphone/Itouch does that kind of calculation, and so, I expect do the other ballistic programs available for it. </div></div>

They sure do - and they're great apps, but they cost money! I'm an open source developer (and database/systems engineer) and I release all of my code for free under the BSD license. Whenever I get this all sorted out and finished you can expect a free app. It will run on the command line of the phone for starters but eventually it will be programmed in Java (or PyQt) to utilize a GUI.
 
Re: Home-made ranging and hold-over "computer system"

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">...they're great apps, but they cost money.</div></div>

True - in the case of Ballistic FTE, less than the cost of a box of 20 rounds of commercial .308 ammunition.

I made my living programming, in both embedded and conventional systems, and retired at the age of 52.

I do not begrudge those who do now what I no longer wish to do the cost of the programs. I have, in fact, paid for programs which I got free, to support the authors of those programs.

In addition, I find rather puzzling the unwillingness to spend trivial amounts of money on something which will help them achieve hits at longer distances, by people shooting rifles and optics which cost several thousand dollars.

Taste varies, I guess.

I have written shooting technical reference web pages which I contribute to the shooting community. I pay for the web site, and there is no advertising. I do that primarily for the military and L.E. shooters I help train, that they may understand better what they are being taught. So, I'm not against doing things without compensation - but I'd a lot rather be doing that than writing code for nothing.

Taste varies, I suppose. Good luck with your efforts.
 
Re: Home-made ranging and hold-over "computer system"

Personally I don't have any issues paying for software, and I have several apps that I do pay for that I feel are worth the money. I have an ipod touch coming that I'll be purchasing the JBM calculator for, so that will be fun to use.

My thing about open source software is that I like to make things available for free that are otherwise not free - for three reasons: 1) once I program something that I find useful I release it in the event that someone else wants to use it or learn from it, 2) some people just don't have money for software (even $20) so I like to provide the option of free software for that purpose. 3) the database software (mysql) and operating sytems (linux/bsd) that I work on are opensource and without that industry I wouldn't have the career that I do, so I feel like it's my duty to give back to a collective of developers that do the same. "What goes around comes around" type of thing.

You can see my database software here: http://kontrollsoft.com - one of the apps (that's free) is an alternative to closed-source software that typically runs $1500/year per server, so a lot of people find that useful. I already have a great salary from my formal job, so managing a software company with billing and licenses and all that just isn't interesting to me. Might as well let others benefit from my coding while I'm at it; it's great for the resume too.

I've been reading your site for the last couple of days when I get time here and there and it's a great resource.
 
Re: Home-made ranging and hold-over "computer system"

Here's the python code for IACO Standard Atmosphere / Pressure Altitude as a Function of Station Pressure. Just put in your station pressure and it prints out the following:

Pressure Altitude (OSL)
Pressure (in Hg)
Temperature (in F)
----
<div class="ubbcode-block"><div class="ubbcode-header">Code:</div><div class="ubbcode-body ubbcode-pre" ><pre>
#!/usr/bin/python
################################################################################
## DATE: 2010-10-31
## AUTHOR: Matt Reid
## WEBSITE: http://themattreid.com
## EMAIL: [email protected]
## LICENSE: BSD http://www.opensource.org/licenses/bsd-license.php
from __future__ import division
import sys

increments = {"35":"-4402","34.75":"-4198","34.5":"-3992","34.25":"-3786","34":"-3578","33.75":"-3369","33.5":"-3159","33.25":"-2947","33":"-2734","32.75":"-2520","32.5":"-2305","32.25":"-2088","32":"-1870","31.75":"-1650","31.5":"-1429","31.25":"-1207","31":"-938","30.75":"-758","30.5":"-531","30.25":"-303","30":"-73","29.75":"159","29.5":"392","29.25":"626","29":"862","28.75":"1100","28.5":"1340","28.25":"1581","28":"1824","27.75":"2069","27.5":"2315","27.25":"2564","27":"2814","26.75":"3066","26.5":"3320","26.25":"3576","26":"3834","25.75":"4094","25.5":"4356","25.25":"4620","25":"4886","24.75":"5155","24.5":"5425","24.25":"5698","24":"5973","23.75":"6251","23.5":"6531","23.25":"6813","23":"7098","22.75":"7385","22.5":"7675","22.25":"7967","22":"8262","21.75":"8560","21.5":"8861","21.25":"9164","21":"9471","20.75":"9780","20.5":"10092","20.25":"10408","20":"10726","19.75":"11048","19.5":"11374","19.25":"11702","19":"12034","18.75":"12370","18.5":"12709","18.25":"13052","18":"13399","17.75":"13750","17.5":"14104","17.25":"14463","17":"14826","16.75":"15194","16.5":"15566","16.25":"15942","16":"16324","15.75":"16710","15.5":"17101","15.25":"17497","15":"17899","14.75":"18306","14.5":"18718","14.25":"19137","14":"19561","13.75":"19992","13.5":"20429","13.25":"20872","13":"21323","12.75":"21780","12.5":"22245","12.25":"22718","12":"23198","11.75":"23686","11.5":"24183","11.25":"24689","11":"25204","10.75":"25728","10.5":"26263","10.25":"26808","10":"27364","9.75":"27931","9.5":"28510","9.25":"29101"}

alt = ["-6000", "-5000", "-4000", "-3000", "-2000", "-1000", "0", "1000", "2000", "3000", "4000", "5000", "6000", "7000", "8000", "9000", "10000", "11000", "12000", "13000", "14000", "15000", "16000", "17000", "18000", "19000", "20000"]

pressure = ["37","35.74", "34.51", "33.31", "32.15", "31.02", "29.92", "28.86", "27.82", "26.82", "25.84", "24.89", "23.98", "23.09", "22.22", "21.38", "20.57", "19.79", "19.02", "18.29", "17.57", "16.88", "16.21", "15.56", "14.94", "14.33", "13.74"]

temp = ["80.4", "76.8", "73.3", "69.7", "66.1", "62.6", "59", "55.4", "51.9", "48.3", "44.7", "41.2", "37.6", "34", "30.5", "26.9", "23.3", "19.8", "16.2", "12.6", "9.1", "5.5", "1.9", "-1.6", "-5.2", "-8.8", "-12.3"]

def pressure_match(P):
y=0
match=[]
for each in pressure:
if P in each:
match.append(y)
y+=1

if len(match) > 0:
if len(match) > 1:
print "\nMultiple matches found, please choose a precision."
print "--------"
for i in match:
print "Pressure (in Hg): %s"%(pressure)
print "--------"
print "Exiting"
sys.exit(1)

return match[0]

P = str(raw_input("Current station pressure(in Hg): "))
try:
print "Pressure Altitude (OSL): %s"%(increments[P])
print "Temperature (in F): N/A"
except:
try:
index = pressure_match(P)
print "Pressure Altitude (OSL): %s"%(alt[index])
print "Pressure (in Hg): %s"%(pressure[index])
print "Temperature (in F): %s"%(temp[index])
except:
print "----------"
print "No record found for entry: %s."%(P)
print" Please specify pressure in increments of .25"
print "Minimum value: 9.25"
print "Maximum Value: 35"
print "----------"</pre></div></div>
 
Re: Home-made ranging and hold-over "computer system"

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lindy</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">...they're great apps, but they cost money.</div></div>

True - in the case of Ballistic FTE, less than the cost of a box of 20 rounds of commercial .308 ammunition.

I made my living programming, in both embedded and conventional systems, and retired at the age of 52.

I do not begrudge those who do now what I no longer wish to do the cost of the programs. I have, in fact, paid for programs which I got free, to support the authors of those programs.

In addition, I find rather puzzling the unwillingness to spend trivial amounts of money on something which will help them achieve hits at longer distances, by people shooting rifles and optics which cost several thousand dollars.

Taste varies, I guess.

I have written shooting technical reference web pages which I contribute to the shooting community. I pay for the web site, and there is no advertising. I do that primarily for the military and L.E. shooters I help train, that they may understand better what they are being taught. So, I'm not against doing things without compensation - but I'd a lot rather be doing that than writing code for nothing.

Taste varies, I suppose. Good luck with your efforts.
</div></div>

I have nothing against paying for a well put-together program/system, but college is my #1 priority right now, so extra cash is pretty thin. I also find it much more satisfying to do a bit of research and put something together yourself and watch it work perfectly. My initial major was CS, but I quickly switched to Chemical Engineering, so programming is more-so just a hobby these days.
 
Re: Home-made ranging and hold-over "computer system"

New Code for mil and moa outputs

Hold:
ClrHome
Disp "V of Target(mph)"
Prompt V
Disp "V of Muzzle(fps)"
Prompt Y
Disp "Distance(yds)"
Prompt D
((V*5280)/3600)*12*((D*3)/Y)-> G
G/(.036*D)-> H
H*3.483->M
ClrHome
Disp "Hold:"
Output(2,1,"Mils"
Output(4,1,"MOA"
Output(3,1,H)
Output(5,1,M)

Range:
ClrHome
Disp "Size(in)"
Prompt I
Disp "Size(Mils)"
Prompt S
(I*27.77)/S->Y
Y*.9144->M
Disp "Range:"
Output(2,1,"Yards")
Output(4,1,"Meters")
Output(3,1,Y)
Output(5,1,M)
 
Re: Home-made ranging and hold-over "computer system"

Don't forget a MOA inch is 1.047
Therefore:
(I/M)*(1/1.047*100)=R

Great idea to use/program the old college calculators! Great job dtkutchu!
Kyle
 
Re: Home-made ranging and hold-over "computer system"

this is good. Putting it into excel now. Lets get to the fun stuff.
 
Re: Home-made ranging and hold-over "computer system"

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 2shot1kill</div><div class="ubbcode-body">TI83 Code for bullet drop? </div></div>

This would depend on the mass of the bullet, muzzle velocity and ambient conditions, etc. One could be made for a specific bullet, but it would be impractical to generalize an equation that would apply for all bullets. It would be best to check the tables for specific rounds (which can be found with a quick google search).
 
Re: Home-made ranging and hold-over "computer system"

I have a new program written up!
This one is for the bullet drop at any distance.

ClrHome
Disp "Range(100's yds)"
Prompt X
ClrHome
Disp "Hold"
*insert equation here->D
D*3.483->M
Output(1,1,"Hold")
Output(2,1,"Mils")
Output(3,1,D)
Output(4,1,"MOA")
Output(5,1,M)

*Alright, here is how to get your equation.
You need to get the ballistics data off the manufacturer website. In this example, I used the .308 Federal.
The drop that they gave me for a 100yd zero was the following:
200yds - 0.6mils
300 - 1.4
400 - 2.4
500 - 3.5
600 - 4.7
700 - 6.1
800 - 7.7
900 - 9.6
1000 - 11.6

Store this data into 2 separate lists.
L1 looks like this:
1
2
3
4
5
6
7
8
9
10

L2 looks like this:
.6
1.4
2.4
3.5
4.7
6.1
7.7
9.6
11.6

You need to run a cubic regression on these lists to find your constants for the equation.
To do this, hit the Stat button, go over to the Calc tab, and select CubicReg.
When you do this, Hit the "2nd" key and hit L1, put a comma, then L2 and hit Enter.it will show you an equation like the following: y=aX^3 + bX^2 + cX + d
it gives you the values for a,b,c, and d. for mine, a=0.0022533023, b=0.0484265734, c=0.5098096348, and d=-0.59
so, you put the equation into the program so it looks like this:
0.0022533023x^3 + 0.0484265734x^2 + 0.5098096348x - 0.59->D

I tested this, and if you round the number it gives you, the drop is correct at all values.
 
Re: Home-made ranging and hold-over "computer system"

My son gave me a TI-36x solar. Would it work for these functions?
 
Re: Home-made ranging and hold-over "computer system"

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ScottS1W</div><div class="ubbcode-body">My son gave me a TI-36x solar. Would it work for these functions? </div></div>
it must be a programmable calculator. I don't believe that this one is, sorry
 
Re: Home-made ranging and hold-over "computer system"

Great work on the p3reg equation! Might want to clarify that the input for X is in the format of (X/100). So 500 yards would be entered as "5". I was entering yard in increments of 100 yards and was getting crazy holdover values.

Here's the same code in Python for everyone. Also I'll be getting an Android phone on Monday (HTC G2) so I'll have verified code after a couple of days. Might get around to putting it into a GUI as well. Note: the following equation multiplies by 2.9 instead of 3.483 because my output matches the JBM output better with that value. YMMV
<div class="ubbcode-block"><div class="ubbcode-header">Code:</div><div class="ubbcode-body ubbcode-pre" ><pre>#!/usr/bin/python
from __future__ import division
import compiler

I = float(raw_input("Target size (inches): "))
M = float(raw_input("Target size (MOA): "))
R = (I/M)
RX = R*100
MILS = .0012*R**3 + .046*R**2 + .60*R - .07 #put your equation on this line
MOA = MILS * 2.9
MI = round(MILS,1)
MO = round(MOA,1)
print "Range in Yards: %i"%(RX)
print "Holdover MILS: %f"%(MI)
print "Holdover MOA: %f"%(MO)</pre></div></div>


 
Re: Home-made ranging and hold-over "computer system"

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 300snipe</div><div class="ubbcode-body">Great work on the p3reg equation! Might want to clarify that the input for X is in the format of (X/100). So 500 yards would be entered as "5". I was entering yard in increments of 100 yards and was getting crazy holdover values.

Here's the same code in Python for everyone. Also I'll be getting an Android phone on Monday (HTC G2) so I'll have verified code after a couple of days. Might get around to putting it into a GUI as well. Note: the following equation multiplies by 2.9 instead of 3.483 because my output matches the JBM output better with that value. YMMV
<div class="ubbcode-block"><div class="ubbcode-header">Code:</div><div class="ubbcode-body ubbcode-pre" ><pre>#!/usr/bin/python
from __future__ import division
import compiler

I = float(raw_input("Target size (inches): "))
M = float(raw_input("Target size (MOA): "))
R = (I/M)
RX = R*100
MILS = .0012*R**3 + .046*R**2 + .60*R - .07 #put your equation on this line
MOA = MILS * 2.9
MI = round(MILS,1)
MO = round(MOA,1)
print "Range in Yards: %i"%(RX)
print "Holdover MILS: %f"%(MI)
print "Holdover MOA: %f"%(MO)</pre></div></div>


</div></div>

Thanks. It has been pretty fun to program these equations and see them work. I can't wait to put them into action. Thanks for the contribution and updating the code in different formats. Great work man
 
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