STEP 01
Tap start, set your interval.
50 mm by default, or 100 mm. A quick calibration confirms your phone is hearing each blow cleanly through the site noise.
Calibration · placeholder
v1 · DCP · early access
Your phone hears the blow.
We log the depth.
Groundtruth turns any iPhone or Android device into a hands-free DCP recorder. Drop the rod, start the test, swing the hammer — every blow lands at the next depth increment, and you can export a clean CSV or a full PDF report before you leave site.
Live test · BH-04
Listening
392
mm
BLOWS
16
double-tap
advance depth
OD
overdrill
sink
self-weight
How it works
Three taps. One report.
The whole loop runs in your hand. No tablet, no rugged case, no wired sensor — just the rod and the phone you already carry.
STEP 02
Swing — we count.
Blow detection runs entirely on-device. Each strike lands at the next increment with sub-second latency, and the phone speaks the new depth back so your eyes stay on the rod. Double-tap to advance, triple-tap to pause — gloves on. Overdrill and sink are one tap each.
Live capture · placeholder
STEP 03
Review and export.
Edit any blow, then email a clean CSV — or generate a PDF report with a satellite site map and CBR plots — before you walk back to the truck. No cloud account required.
Review · placeholder
What's in v1
A focused, honest tool.
Groundtruth today is one job done well: dynamic cone penetrometer tests, captured by ear. The roadmap is wide open — and shaped by the engineers using it.
Shipping at launch
v1.0 · early access
Automatic blow tracking
Your phone counts every hammer blow on-device and logs it at the right depth — no tallying, no clicker, no notebook.
One-tap reports
Export a CSV, or generate a full PDF report with plots and a method note — straight from site. (PDF on Android first.)
GPS site maps
Every test is geotagged and pinned on a satellite Test Location Plan that drops straight into your report.
Estimated CBR%
California Bearing Ratio from blow counts — Austroads, USACE or TRL — plotted against depth. Estimates only, clearly labelled.
Projects
Group tests into projects, filter and sort them, and keep every borehole organised.
Works offline
Every test stores on the device. No internet, no account needed.
On the way
co-designed with users
Project sync
Local projects today; tests roll up to a workspace your team can review.
PDF reports on iOS
Generate the full report straight from iPhone, not just Android.
More test types
SPT, hand-augers, pressuremeter — driven by what you're running.
Auto-classification
Stratigraphy suggestions from the depth-blow signature.
Org accounts
Per-seat licensing, audit trail, custom export schemas.
We're building these with teams, not for an imagined market. If your shop runs DCPs every week and you'd like a hand on the wheel — talk to us.
Who it's for
Built for the people holding the rod.
Field-grade ground truth for the engineers, surveyors and crews whose hands are full and whose pencils get muddy.
01
Geotechnical & civil field staff
One engineer, one rod, one phone. No tablet, no laptop in the truck.
02
Independent consultants
Run the test, send the report, invoice the client — same afternoon.
03
Site investigation crews
Consistent depth logs across every operator. No more arguing over handwriting.
04
Back-office geotech teams
Projects keep every test organised today. (Coming soon) team sync and auto-classification.
Questions
Reasonable scepticism, answered.
Didn't see your question? Email info@getgroundtruth.app — we read everything.
Does it really work in noisy site conditions?
Calibration sets a noise floor before each test. The detector is tuned to the impulsive signature of a hammer-on-rod strike — generators, traffic, and chatter don't trigger it. Edge cases get flagged in review for you to confirm or drop.
What happens to my data?
By default, nothing leaves your phone. Tests live locally; you choose whether to email a CSV or generate a PDF report and share it. We don't have a server to lose.
What's stopping me just typing into a spreadsheet?
Honestly — nothing. Some engineers will keep doing exactly that. Groundtruth is for people whose hands are full and whose pencils get muddy.
Is the CBR% a substitute for a lab test?
No. CBR% is estimated from blow counts using a published correlation (Austroads, USACE or TRL — your choice), and every report says so. It's a fast field indicator, not a replacement for laboratory CBR testing or engineering judgement.
Can you support a non-DCP test type?
Probably, eventually. If you'd run it weekly, tell us — that's how the roadmap moves.
When can I get it?
Early access is opening to a small cohort first. Email us and we'll get you on the list.
Stop logging depths in a soggy notebook.
Get on the early access list. Run a test on the way back to your desk. Decide for yourself.