Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Adding SEN0322 O2 Sensor Driver Support #1075

Open
wants to merge 2 commits into
base: public
Choose a base branch
from
Open
Show file tree
Hide file tree
Changes from 1 commit
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
23 changes: 23 additions & 0 deletions examples/drivers/sensors/sen0322/main.js
Original file line number Diff line number Diff line change
@@ -0,0 +1,23 @@
import Sensor from "embedded:sensor/OxygenGasSensor-OSensor/SEN0322";
import Timer from "timer";

const knownOxygenVal = 20.9; // Known concentration of oxygen in the air, for calibration
const oxygenMV = 0; // The value marked on the sensor, set to 0 unless otherwise required

const sensor = new Sensor({
sensor: {
...device.I2C.default,
io: device.io.I2C
}
});

sensor.configure({
vol: knownOxygenVal,
mv: oxygenMV
});

Timer.repeat(() =>
{
const sample = sensor.sample();
trace(`O2: ${sample.O} ppm\n`);
}, 500);
9 changes: 9 additions & 0 deletions examples/drivers/sensors/sen0322/manifest.json
Original file line number Diff line number Diff line change
@@ -0,0 +1,9 @@
{
"include": [
"$(MODDABLE)/modules/io/manifest.json",
"$(MODDABLE)/modules/drivers/sensors/sen0322/manifest.json"
],
"modules": {
"*": "./main"
}
}
9 changes: 9 additions & 0 deletions modules/drivers/sensors/sen0322/manifest.json
Original file line number Diff line number Diff line change
@@ -0,0 +1,9 @@
{
"modules": {
"embedded:sensor/OxygenGasSensor-OSensor/SEN0322": "$(MODDABLE)/modules/drivers/sensors/sen0322/sen0322"
},
"preload": [
"embedded:sensor/OxygenGasSensor-OSensor/SEN0322"
]
}

80 changes: 80 additions & 0 deletions modules/drivers/sensors/sen0322/sen0322.js
Original file line number Diff line number Diff line change
@@ -0,0 +1,80 @@
import Timer from "timer";
Copy link
Collaborator

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Our ECMA-419 sensor drivers usually include a header with:

  • Copyright notice
  • Full name of part
  • Link to relevant manufacturer data sheets
  • Link to any implementations used as a reference


const Register = Object.freeze({
OXYGEN_DATA: 0x03, ///< register for oxygen data
USER_SET: 0x08, ///< register for users to configure key value manually
AUTUAL_SET: 0x09, ///< register that automatically configure key value
GET_KEY: 0x0A ///< register for obtaining key value
});

const I2C_ADDR = 0x73;

class SEN0322
{
#io;
#key;
#onError;
Copy link
Collaborator

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

#onError is unused


constructor(options) {
this.#io = new options.sensor.io({
address: I2C_ADDR,
hz: 100_000,
...options.sensor
});
this.#onError = options.onError
Copy link
Collaborator

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

#onError is unused


}

configure(options)
{
if (undefined !== options.vol)
{
const vol = options.vol;
const mv = options.mv ?? 0;
if (vol < 0 || vol > 25)
throw new RangeError("invalid O2 concentration (must be 0-25)");
else
Copy link
Collaborator

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

The throw above will always, so the content of this else clause can be directly inline below.

{
const io = this.#io;
let keyValue = vol * 10;

if (mv < 0.000001 && mv > (-0.000001))
io.write(Uint8Array.of(Register.USER_SET, keyValue));
else
{
keyValue = (vol / mv) * 1000;
io.write(Uint8Array.of(Register.AUTUAL_SET, keyValue));
}
}
}
}
#setKey()
{
const io = this.#io;
io.write(Uint8Array.of(Register.GET_KEY));
const curKey = (new Uint8Array(io.read(1)))[0];
if (curKey)
this.#key = curKey / 1000.0;
else
this.#key = 20.9 / 120.0;
}
close()
{
this.#io.close();
Copy link
Collaborator

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

close is defined to be safe to call more than once. This implementation will throw after the first time it is called. We typically use this.#io?.close() here instead.

this.#io = undefined;
}
sample()
{
const io = this.#io;
let ret = {};
Copy link
Collaborator

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This is allocated very far from when it is used. Maybe simplify to:

return {O: oxygenPercent * 10_000}; // O2 concentration in PPM

this.#setKey();
io.write(Uint8Array.of(Register.OXYGEN_DATA));
Timer.delay(100);
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Hmm, this pauses the VM. I would not use this driver for this alone. Would be nice to find a different way to code this. At the very least document it at the top or readme.

Copy link
Collaborator

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Agreed. A simple solution would be to have a timer in the driver to poll the value every 100ms. The driver would store the most recent value and return it from sample().

Because sample()1 is allowed to return undefined`, the driver could clear the cached sample after it is read once. The benefit is that a caller will know when they have a truly new reading.

const rxbuf = new Uint8Array(io.read(3));
const oxygenPercent = ((this.#key) * ((rxbuf[0]) + (rxbuf[1] / 10.0) + (rxbuf[2] / 100.0)));
Copy link
Collaborator

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

There's a diversity of approaches to parenthesis in this source file.

For example, this line is very careful about parenthesizing just about everything (including this.#key and the entire expression).

Compare to line 42 which only parenthesizes a number literal (mv < 0.000001 && mv > (-0.000001)). More consistent style with this repository would be ((mv < 0.000001( && (mv > -0.000001))) or a better way to express between, (-0.000001 < mv) && (mv < 0.000001)). That could apply to line 34 as well.

ret.O = oxygenPercent * 10000; // O2 concentration in PPM
return ret;
}

}
export default SEN0322;