Project · draft
Drinking-Water TDS and Temperature Meter
- beginner
- 4-6 hours
SDG 6 · Clean Water and Sanitation
Lets households and schools compare water sources and check whether a filter or RO unit is still reducing dissolved solids.
Safety notes
- TDS is not a safety test: it does not detect bacteria, arsenic, fluoride, nitrate or other contaminants. Never use it to decide water is safe to drink; use an accredited lab test for that.
- Do not drink a sample after the probes have been in it. Keep the board and USB side dry.
Draft and unofficial, not affiliated with Fab Academy or the United Nations. Check prices, GST and parts before you buy.
Summary
Dip the two probes in a sample: the OLED shows TDS (ppm) and water temperature, and logs readings over USB serial so you can compare tap, borewell, filtered and RO water.
What it teaches
Read an analog conductivity-based TDS probe, apply temperature compensation from a 1-Wire DS18B20, calibrate against a reference solution, and understand what TDS can and cannot tell you about water.
Topics it touches, in Fab Academy-style terms:
- Input devices
- Embedded programming
- 3D scanning and printing (optional probe holder)
Parts list
Parts cost
Some parts are not priced yet, so there's no total.
3 required parts are marked not priced yet below. Where a price is known it is shown per part, GST-inclusive as the seller listed it on 24 Oct 2026, with the GST rate unverified. Shipping is not included.
| Part | Qty | Unit | Price, GST-incl. as listed | Line cost | GST | Source |
|---|---|---|---|---|---|---|
| Seeed Studio XIAO RP2040 Development Boardxiao-rp2040 | 1 | pcs | ₹513 | ₹513 | GST unverified, typically 18% | Robocrazeread 24 Oct 2026 |
| Analog TDS (total dissolved solids) sensor module with probetds-sensor-module | 1 | pcs | not priced yet | not priced yet | GST unverified | no seller yet |
| DS18B20 waterproof temperature probe (1-Wire), ~1 m leadds18b20-waterproof | 1 | pcs | not priced yet | not priced yet | GST unverified | no seller yet |
| 4.7 kOhm resistor, through-hole (pack of 10)resistor-4k7-x101-Wire pull-up; uses 1 | 1 | set | not priced yet | not priced yet | GST unverified | no seller yet |
| 0.96 Inch OLED Display Module SPI/I2C 4pin Blue Coloroled-096-i2cI2C 0x3C | 1 | pcs | ₹167 | ₹167 | GST unverified, typically 18% | Robocrazeread 24 Oct 2026 |
| 400 Tie Points Solderless Breadboardbreadboard-half-400 | 1 | pcs | ₹39 | ₹39 | GST unverified, typically 18% | Robocrazeread 24 Oct 2026 |
| Male to Male Jumper Wires (20cm) (20pcs)jumpers-m2m-20cm-20Pack: pack of 20 male-male 20cm | 1 | set | ₹31 | ₹31 | GST unverified, typically 18% | Robocrazeread 24 Oct 2026 |
| Male to Female Jumper Wires (20cm) (20pcs)jumpers-f2m-20cm-20Pack: pack of 20 male-female 20cm | 1 | set | ₹28 | ₹28 | GST unverified, typically 18% | Robocrazeread 24 Oct 2026 |
| Part | Qty | Unit | Price, GST-incl. as listed | Line cost | GST | Source |
|---|---|---|---|---|---|---|
| Type C USB Cable (1 metre)cable-usb-c-1mSkip if you already have a data-capable USB-C cable | 1 | pcs | ₹65 | ₹65 | GST unverified, typically 18% | Robocrazeread 24 Oct 2026 |
| Premium 1.75MM HS PLA 1 KG 3d Printer Filament - Cement grey Colourfilament-pla-1kgOptional probe holder / case; Fab Lab stock | 1 | pcs | ₹741 | ₹741 | GST unverified, typically 18% | Robocrazeread 24 Oct 2026 |
| Optional extras total, GST-inclusive as listed by the seller | ₹806 | |||||
The Part column links to the shared catalogue. Units are pcs, m, g, sheet or set, and a "set" is the seller's pack, as noted per part.
Tools you will need
- Laptop with MicroPython/Thonny or Arduino-Pico
- Clean sample cups; TDS calibration solution (unpriced consumable)
Build notes
Step-by-step build notes have not been written yet for this draft. The summary, the topics above and the parts list are what exists so far.
How to buy
There is no online checkout. To buy or import these parts, email info@curiosta.com and say what you need. The button opens your own email app with a draft; nothing is sent until you send it.
Prices on this site are third-party seller listings, not a Curiosta quote. Ask by email for availability, price and GST.