Documentation sections

Optical Proximity Sensor Range

POSThttps://rftools.io/api/py/v1/calculate

Slug optical-sensor-range. Compare optical proximity sensor configurations by detection factor. Analyze emitter power, detector responsivity, and reflectivity tradeoffs.

Inputs

Send every one of these in inputs, in the units shown. Most are required: a call without one is refused (400) and costs nothing; one the calculator can do without takes the default shown. An input outside its range is still computed and flagged in the provenance.

Inputs of optical-sensor-range
Name	Unit	Range	Default	Description
emitterPowernumber	mW	at least 0.001	10	Emitter Power
detectorSensitivitynumber	A/W	at least 0.001	0.6	Typical silicon photodiode: 0.5–0.8 A/W at 850 nm
targetReflectivitynumber	%	0.1 … 100	90	Target Reflectivity
safetyFactornumber	none	at least 1	1.5	Safety Factor

Outputs

Returned in values, by key. A value that is unbounded or undefined is null.

Outputs of optical-sensor-range
Field	Unit	Description
maxRangeheadline	none	Relative Detection Factor
normalizedRange	none	Nominal Detection Factor

Calling it

Calculate: one call, the request and response in full, and its errors.
Batch: this calculator with others, or a sweep, in one request.
Solve for a target: the value of one input that brings an output to a target.

curl -X POST https://rftools.io/api/py/v1/calculate \
  -H "X-API-Key: $RFTOOLS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "slug": "optical-sensor-range",
    "inputs": {
      "emitterPower": 10,
      "detectorSensitivity": 0.6,
      "targetReflectivity": 90,
      "safetyFactor": 1.5
    }
  }'

import rftools

client = rftools.Client()  # reads RFTOOLS_API_KEY, or the key `rftools login` saved

result = client.calculate("optical-sensor-range", {
    "emitterPower": 10,
    "detectorSensitivity": 0.6,
    "targetReflectivity": 90,
    "safetyFactor": 1.5,
})
print(result.values)
print(result.warnings, result.provenance.formula_ref)

const response = await fetch("https://rftools.io/api/py/v1/calculate", {
  method: "POST",
  headers: {
    "X-API-Key": process.env.RFTOOLS_API_KEY,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    "slug": "optical-sensor-range",
    "inputs": {
      "emitterPower": 10,
      "detectorSensitivity": 0.6,
      "targetReflectivity": 90,
      "safetyFactor": 1.5
    }
  }),
});
console.log(response.status, await response.json());

package main

import (
	"bytes"
	"fmt"
	"io"
	"net/http"
	"os"
)

func main() {
	body := []byte(`{
	  "slug": "optical-sensor-range",
	  "inputs": {
	    "emitterPower": 10,
	    "detectorSensitivity": 0.6,
	    "targetReflectivity": 90,
	    "safetyFactor": 1.5
	  }
	}`)
	req, err := http.NewRequest("POST", "https://rftools.io/api/py/v1/calculate", bytes.NewReader(body))
	if err != nil {
		panic(err)
	}
	req.Header.Set("X-API-Key", os.Getenv("RFTOOLS_API_KEY"))
	req.Header.Set("Content-Type", "application/json")
	res, err := http.DefaultClient.Do(req)
	if err != nil {
		panic(err)
	}
	defer res.Body.Close()
	out, _ := io.ReadAll(res.Body)
	fmt.Println(res.Status, string(out))
}

application/json

{
  "slug": "optical-sensor-range",
  "values": {
    "maxRange": 1.5491933384829668,
    "normalizedRange": 2.32379000772445
  },
  "warnings": [],
  "errors": [],
  "provenance": {
    "method": "calculator:optical-sensor-range",
    "version": "api@3f2c1a9b04de",
    "formulaRef": null,
    "assumptions": [],
    "validRange": {
      "status": "inside",
      "bounds": {
        "emitterPower": {
          "min": 0.001,
          "max": null,
          "unit": "mW"
        },
        "detectorSensitivity": {
          "min": 0.001,
          "max": null,
          "unit": "A/W"
        },
        "targetReflectivity": {
          "min": 0.1,
          "max": 100,
          "unit": "%"
        },
        "safetyFactor": {
          "min": 1,
          "max": null,
          "unit": ""
        }
      },
      "outside": [],
      "model": null
    },
    "computedAt": "2026-09-24T14:05:11.003Z",
    "inputs": {
      "emitterPower": 10,
      "detectorSensitivity": 0.6,
      "targetReflectivity": 90,
      "safetyFactor": 1.5
    },
    "seed": null,
    "elapsedSeconds": 0.003
  }
}

{
  "detail": [
    {
      "type": "float_parsing",
      "loc": [
        "body",
        "inputs",
        "emitterPower"
      ],
      "msg": "Input should be a valid number, unable to parse string as a number",
      "input": "abc"
    }
  ]
}

An input sent as text. Nothing was counted.

{
  "detail": "More than 120 requests in 60 seconds from this address.",
  "errorKind": "rate_limited",
  "limit": 120,
  "windowSeconds": 60,
  "upgradeUrl": "https://rftools.io/pricing/"
}

Too many requests in a minute, with Retry-After.

Same inputs on the calculator pageOptical Proximity Sensor Range, at these values