I wrote rstring as an excercise to learn Rust, a pretty modern programming language.
rstring at a GitHub repository
Compilation instructions are at the bottom of this page.
The Rust programming language first appeared around 2010 (today is mid 2016). The language prioritizes memory safety, especially in concurrency, and it mixes together quite a few modern programming paradigms: functional, imperative, and object oriented. Rust aims to provide all of this with little run-time cost by using a clever compiler and strict language rules.
Coming from C programming, I think Rust feels like C but with a lot more rules. With Rust, dumb programming mistakes involving memory and types are banned at compile-time. For example, Rust has a sophisticated data ownership system that restricts the mutability (ability to change the value) of data in memory. As a result of these rules, a lot of time is spent fighting the compiler, rather than debugging the code at run-time. You'll still need to be careful of things like your array indices' range, but you can rely on the compiler to slap you over and over again when you try to be clever with pointers and dynamic memory.
In addition to the language, Rust also has the Cargo package manager and build environment. It allows the programmer to quickly get libraries from an online repository and manage local versions. It also has an interface for doing both unit tests, full system verification, and documentation generation. It is basically a one button solution.
I'm quite hopeful about Rust.
rstring is a command line program that finds the closest preferred value (E-series) resistors to produce "tap" voltages from a resistor divider, given the total resistance and the source voltage applied across the divider.
If no taps are given, the program simply finds the resistor that is closest to the given total resistance.
Essentially, you give it voltages and it gives you a string of resistors, hence the name rstring
$ rstring Usage: rstring [Opt. E Series] [Opt. Format] [Source Voltage] [Total Resistance] [Tap Voltages...] E Series options (defaults to E12 series if not given): -e6, -e12, -e24, -e48, -e96, -e192, -ideal Format options (defaults to human readable if not given): -csv, -spice Description: Finds the closest preferred value resistors to produce "tap" voltages from a resistor divider, given the total resistance and the source voltage applied across the divider. If no taps are given, the program simply finds the resistor that is closest to the given total resistance.
$ rstring -e12 10 54321 1 1.5 5.4 2.6 3.9 8.1 | 10 V | [ ] 1.0000e4 Ohms |---- Tap 1: 8.1785e0 V (Ideal: 8.1 V, Error: 0.97%) | [ ] 1.5000e4 Ohms |---- Tap 2: 5.4463e0 V (Ideal: 5.4 V, Error: 0.86%) | [ ] 6.8000e3 Ohms |---- Tap 3: 4.2077e0 V (Ideal: 3.9 V, Error: 7.89%) | [ ] 6.8000e3 Ohms |---- Tap 4: 2.9690e0 V (Ideal: 2.6 V, Error: 14.19%) | [ ] 6.8000e3 Ohms |---- Tap 5: 1.7304e0 V (Ideal: 1.5 V, Error: 15.36%) | [ ] 2.7000e3 Ohms |---- Tap 6: 1.2386e0 V (Ideal: 1 V, Error: 23.86%) | [ ] 6.8000e3 Ohms | | 0 V Current Consumption: 0.000182 Amperes Total Resistance: 5.4900e4 Ohms (Ideal 5.4321e4 Ohms, Error: 1.07%)
$ rstring -e12 -spice 10 54321 1 1.5 5.4 2.6 3.9 8.1 * Resistor Divider String * Input Voltage: 10 V * Total Resistance: 54900 Ohms .SUBCKT RDIV VPOS VNEG TAP1 TAP2 TAP3 TAP4 TAP5 TAP6 R1 VPOS TAP1 10000 R2 TAP1 TAP2 15000 R3 TAP2 TAP3 6800 R4 TAP3 TAP4 6800 R5 TAP4 TAP5 6800 R6 TAP5 TAP6 2700 R7 TAP6 VNEG 6800 .ENDS
$ rstring -e12 -csv 10 54321 1 1.5 5.4 2.6 3.9 8.1 | column -t -s, SourceVoltage 10 Current 0.00018214936 Item Value Ideal Error% TotalResistance 54900 54321 0.010658861 Tap1 8.178507 8.1 0.9692157 R1 10000 Tap2 5.446266 5.4 0.8567792 R2 15000 Tap3 4.2076507 3.9 7.888476 R3 6800 Tap4 2.9690351 2.6 14.193665 R4 6800 Tap5 1.7304195 1.5 15.361301 R5 6800 Tap6 1.2386162 1 23.861622 R6 2700
The rstring was written in Rust with the Cargo environment. You'll need to install Cargo or at least the rustc compiler.
At the top level directory, run
cargo build --release
and the executable will be built as target/release/rstring
In the src directory, run
rustc main.rs -o rstring
and the executable will be built as rstring
Written on the 19th of July in 2016