no variable selected
—
pick a variable of interest, top left
not set
not saved to disk yet
—
| # | Label | Timestamp | Value | A |
|---|
| Timestamp | Elapsed (s) | Value | Label |
|---|
no file loaded — or drop a .csv anywhere on this tab
click a cell to edit — the chart follows as you go
Off: the channel stays yours to pick from
“+ Variable of interest”, top left.
Copies of recordings made without a file picker (Android). They stay until you delete them.
| Parameter | Set to | Latest reported | Status |
|---|
How it works
Apply sends
Set, <name>, <value> on the serial link.
Any incoming line of the form Gain: 16x, Gain = 16,
Set, Gain, 16x, Report, Gain, 16x
— or a CSV row under a header carrying that column — updates
“Latest reported”, and the status tag says whether the device confirmed the value you chose.
Lines: 0
RX: 0 B
TX: 0 B
Read me
Serial Data Logging App
Reads a sensor over USB and saves the numbers as .csv files for Excel. For the
spectrophotometer it also works out absorbance / OD, calibration curves and growth curves.
Start
OD600 Cell growth (the default). Uses the 580–600 nm channel, the AS7341's closest to 600 nm.
DNS assay Reducing sugars at 515 nm. Uses the 505–525 nm channel.
Any device Any other serial sensor. You choose the value with + Variable of interest.
Choose in Settings › What are you measuring? The choice shows as a tag at the top of the page.
1 · Plug in
Connect the spectrophotometer by USB.
2 · Connect
Click the USB button (top right). Pick the port the first time.
3 · Gain
Number stuck at its maximum: lower the gain (Settings). Very small: raise it.
Measure
1 · Blank in
Medium, or water with reagents. No cells, no sugar.
2 · Steady
Wait for the green ● Steady tag (last 8 s within 1 %).
3 · Set blank
Set blank from current reading in the Blank box. That value is I0.
4 · Samples
Each standard or sample: wait for Steady, type a label, press Save.
The first Save asks where to put the file; every Save after that is written straight away.
Use clear labels: Std 0.5 g/L, Culture 2 h.
Absorbance
A = log10( I0 / I )
I0 = blank, I = sample. Half the blank's light gives A = 0.30.
Switch Intensity ⇄ A515 / OD600, above the big number and on Trend. View only: files always hold both.
Re-blank Each saved point keeps the blank it was measured against, so a new blank between sets is safe.
Take the blank again when the Blank box warns you
- the gain changed since the blank;
- the blank is over 30 min old (the light may drift);
- a sample reads higher than the blank (A < 0: wrong blank, bubbles, or a smudged cuvette).
Tabs
Reading The live number, the Blank box, and the saved points with their A / OD.
Trend Live plot since you connected, in intensity or A / OD, with saved points marked and the Steady tag.
Analysis Works on your saved points:
| Analysis | You enter | You get |
|---|---|---|
| Calibration curve DNS assay | Each standard's concentration; samples' dilution | C = k × A through the origin (as Excel LINEST(C, A, FALSE)), k, R², each sample's concentration |
| Growth curve OD600 | Dilution; untick lag or stationary points | OD × dilution against time, growth rate μ, doubling time |
| Time series any .csv | X and Y columns | Summary statistics, linear fit, moving average |
Settings What you're measuring, the automatic channel, the gain.
Console Raw lines from the device, and a box to send commands.
Files
| File | Made by | Columns |
|---|---|---|
| Saved points | Save (written straight away) | n, label, time, reading, blank I0, A / OD |
| Recording | ● Record (top right), every 2 s | time, reading, blank I0, A / OD, label |
| Analysis table | Download table (Analysis) | the table and the fit, for your report |
Computers & phones
Windows / Mac Chrome or Edge. Firefox and Safari can't reach USB devices.
Ubuntu Google Chrome. If the port won't open, the message under the USB button gives the one-off fix (a udev rule, or the dialout group).
Android Chrome with a USB-C OTG cable. Native-USB boards only (ESP32-S3/C3/C6 and similar). Recordings download when you stop; a copy stays in Settings.
Problems
| What you see | What to do |
|---|---|
| The port won't open | Close other tabs, the Arduino serial monitor or any program using it; try again. |
| No number appears | Open Console to check lines arrive; check Settings shows the right measurement. |
| A / OD switch greyed out | Set a blank first (Blank box on Reading). |
| Saved points not in a file | Use Download next to the saved points. |
Feedback
Found a problem, or have an idea? Tell us on GitHub (free account). The link fills in your browser and settings. No account? Tell your lab instructor or TA.