`fiftyG.js`: Calibrate your digital scales with every day items
Tags: javascript, node, travel
Published: 2023-05-30 21:43:39

---
title: `fiftyG.js`: Calibrate your digital scales with every day items
published: true
description: A JavaScript for calibrating your digital scales with every day items and showing how coding skills are awesome!
tags: javascript, node, travel
cover_image: https://dev-to-uploads.s3.amazonaws.com/uploads/articles/hvvwl70u1oqcxjm7e5kj.jpg
# Use a ratio of 100:42 for best results.
# published_at: 2023-05-31 02:50 +0000
---

## WTF

I use the skills learned in my profession, skills which started as baby steps in my personal computing life, to enhance my personal life. I use them every day.

I'm a digital nomad. I've been "nomading" for 15 years. Before "digital nomad" was even a term "Mi maleta es mi casa".

Any traveller'll tell you luggage weight matters. I used to keep mine below 15kg: laptop, clothes, cameras, equipment, the bags which hold it all. But them airlines started lowering the cabin allowance and raising the price of checked-in. Greedy ffers.

Now I do 10kg. For everything. My whole life - in a bag. I internally mock them tourists with their 50kg wheelie bins going on a two week holiday to a place I intend to stay a year, with everything on my back like a hermit crab with missing legs, weighing less than their excitement.

I'm obsessed with weight. I know how much everything in my bag weighs. I have 10 SanDiskUltraFitUSB31 thumb drives in a little purse I got in Ecuador which has a herbal design. It weighs 43.1g. That's with 4 little cowrie shells in it as well. I have a DynoVap vaporiser protected in an aluminium tube. 193.85g.

I have two scales. One for my luggage and some digital scales for... herbs... for cooking... (cough cough)... for checking the weight of any herbs I get... for cooking... (cough)... Very useful for establishing the integrity of your herb dealer.

But those scales occasionally need re-calibrating; and the calibration weight is 50g.

I have a choice. Do I add a bronze 50g weight to my already sparse luggage - perhaps leave those 10 SanDiskUltraFitUSB31 thumb drives in a little purse I got in Ecuador behind?! NO! I need those 10 SanDiskUltraFitUSB31 thumb drives in a little purse I got in Ecuador.

But I'm a coder. And coding is fun.

So I wrote a script. Coders can write this script. Any one can use this script, if you follow this simple recipe below... to make 50 grams of calibration weight for your digital scales... for herbs.

## TF

You already know the exact weight of many things in your possession, to a gram. On Wikipedia, for instance, you'll find the weight of nearly every coin in circulation. The weight of your AirPods, the charger: all published by Apple. Need I go on? That battery for your digital scales? You can probably find out how much it is supposed to weigh. Do you happen to have any SanDiskUltraFitUSB31 thumb drives? I do?! They weigh 1.3g each.

To make 50g, all you need to do is combine those items in a precise way. Which is chore. Unless you are a coder. Because coding is fun.

## Prerequsites

- You need to have Node and NPM installed on your PC.
- You need to know how to use a command line on your PC.
- If your PC isn't UNIX based, you need to know how to translate these commands to DOS prompt or PowerShell (hehheh - see what I did there?)

## F!

Let's F-ing do this.

Have to a place where you put non-essential, useful-to-refer-back-to-later scripts. I have a repo called **jeeves**. It contains cheat docs, sample projects, things I stole from StackOverflow, things ChatGPT wrote for me, and scripts I wrote - in many runtimes - all "handed to me on a plate" for when I need them. I'm a traveller. Sometimes I don't have the internet.

**jeeves** is my StackTrickle. You should make your own **jeeves**.

The root folder for my collection of non-essential, useful-to-refer-back-to-later scripts is `cd ~/Dev/eliotim/jeeves/engage`. I dunno what yours is. 

- Open a command line shell.

```shell
cd ~/Dev/eliotim/jeeves/engage
mkdir fiftyG
cd fiftyG
touch fiftyG.js
```

Your digital scales might calibrate with 100g or 25g. Change your script as required.

_WAIT!: If it's anything over 1000g, remember that 1L of water is 1000g + plastic. You probably don't need this script._

- Open `~/Dev/eliotim/jeeves/engage/fiftyG/fiftyG.js` in your favourite code editor.

- Paste the following:

```javascript
// The weight goal.
const GOAL = 50.0 // grammes

// How much PRECISION to seek... smaller takes longer.
const PRECISION = 0.01 // grammes

// The weights of any everyday items you have which can be
// established without weighing them!
const KNOWN_WEIGHTS = {
  EUR1: 2.3,
  EUR2: 3.06,
  EUR5: 3.92,
  EUR10: 4.1,
  EUR20: 5.74,
  EUR50: 7.8,
  EUR100: 7.5,
  EUR200: 8.5,
  USD100: 8.1,
  CAD100: 6.27,
  AUS100: 9,
  AABattery: 23.16,
  AAABattery: 11.1,
  WeightTray: 5.62,
  EarPod: 5.4,
  SanDiskCruzerBlade: 3.33,
  SanDiskUltraFitUSB31: 1.3,
  CorsairFlashVoyager8: 18.76,
  CorsairFlashVoyager64: 15.28,
  MentosMint: 1.3,
}

// Don't make this too long!
let ITEMS_IN_MY_POSSESSION = [
  "SanDiskUltraFitUSB31",
  "SanDiskUltraFitUSB31",
  "SanDiskUltraFitUSB31",
  "SanDiskUltraFitUSB31",
  "SanDiskUltraFitUSB31",
  "SanDiskUltraFitUSB31",
  "SanDiskUltraFitUSB31",
  "SanDiskUltraFitUSB31",
  "SanDiskUltraFitUSB31",
  "SanDiskUltraFitUSB31",
  "EUR1",
  "EUR2",
  "EUR5",
  "EUR10",
  "EUR10",
  "EUR10",
  "EUR20",
  "EUR20",
  "EUR100",
  "EUR100",
  "EUR100",
  "EUR200",
  "EUR200",
  "EarPod",
  "EarPod",
].map((w) => KNOWN_WEIGHTS[w])

/** @TODONT edit the rest (unless you can do better than me) */

// Somewhere to hold our best combos.
let OUT = new Map()

// A function to keep looking for the perfect weight combos.
function findCombinationToGoal(goal, numbers, partial) {
  let n = 0
  // The list of combos being checked can not be undefined.
  partial = partial || []
  let projection = partial.reduce((a, b) => a + b, 0)
  // check if the partial sum equals goal
  if (PRECISION > Math.abs(goal - projection)) {
    let HIT = partial.sort().map((weight) => {
      return Object.keys(KNOWN_WEIGHTS).find(
        (key) => KNOWN_WEIGHTS[key] === weight
      )
    })
    let lines = HIT.join(" / ")
    OUT.set(lines, projection)
  }
  // Recursively call this function combining different items
  // until you get the list of perfect combos.
  for (var i = 0; i < numbers.length; i++) {
    n = numbers[i]
    remainingNumbers = numbers.slice(i + 1)
    findCombinationToGoal(goal, remainingNumbers, partial.concat([n]))
  }
}

console.log("Please wait. This might take a few moments.")

// Call the function to find the combo!
findCombinationToGoal(GOAL, ITEMS_IN_MY_POSSESSION, [])

// Just show the top 3 results by fewest items meeting
// the precision required.
console.table(
  [...OUT.entries()]
    .sort((a, b) => a[0].split(" / ").length - b[0].split(" / ").length)
    .slice(0, 3))
```

- Close the file.

- Run it.

```shell
cd ~/Dev/eliotim/jeeves/engage/fiftyG
node fiftyG.js
```

- Collect the best combo (fewer items is easier).

- Re calibrate your digital scales.

- Buy herbs.

- Check weight of delivery.

- Tip the herb sales-person if they have "herb integrity".

- Spread the word if they do not.

## In conclusion

Your coding skills can help you solve much more than commercial problems. And if you don't code: Learn: even if it doesn't make you money it can save you money.