The virtual fence collar
you can build.
Open designs, off-the-shelf parts, and open integration so any software can run it. No lease, no lock-in.
Assembled by openpasture, pricing expected to start at $249. Fully refundable $50 reservation. Full disclaimer.
- 2.2 m
- First-fix accuracyPrototype 01, open sky
- ≤ 2.5 m
- Accuracy targetV1, open pasture
- 60+ d
- Without sunV1 target, solar top unit
- < 2 min
- Setup per collarV1 target: scan, strap, done
Most collars are leased. This one is yours.
Most virtual fencing comes on a yearly subscription, locked to one company's software. Stop paying, and the fence stops.
| Question | Leased | OpenCollar |
|---|---|---|
| How you get it | Yearly subscription | Buy it, or build it |
| If you stop paying | The fence stops | Nothing to stop paying |
| Software | Theirs only | Any software |
| Designs | Closed | Published |
| Repair | Not yours to open | A screwdriver and a parts list |
Opening the designs.
Each piece is published as it settles.
- Parts listpublished
- Collar protocoldrafted
- Firmwarein progress
- Enclosure and CADV1 in design
- Repair guidesplanned
Get the designs first.
Leave an email and you'll hear when each piece goes public.
You're on the list. Cody will write when designs go up.
That didn't send. Try again in a moment, or email cody@openpasture.dev.
Sun on top, sky at the crown.
Everything electronic lives in one sealed top unit, held with gaskets and screws instead of potting, so every part can be replaced.
The weight at the bottom does work. It's a bay for ballast, a Battery Extension, or a camera module.
The fence runs on the collar, so it holds with no signal.
The full design and targetsRuns with any software.
The collar speaks a documented protocol, with open-source code to speak it back. Boundaries go down, acknowledgements and positions come up.
- yoursYour own scripts and tools
- researchData pipelines for trials and studies
- farm appsAny app that implements the protocol
- openpastureFirst-party software, in development, that decides each day's move. Where it's headed.
A new boundary, down to every collar
{
"version": 42,
"effective_at": "2026-09-25T12:30:00Z",
"boundary": [[-92.41, 38.12], …],
"warn_m": 10
}
Each collar answers
{ "version": 42, "status": "applied" }
From the draft collar protocol.
reservations open
Assembled
from$2491
Built and tested by openpasture. A $50 reservation per collar holds your place; you confirm your order when production is ready.
- Top unit, strap, and ballast module
- Battery Extension and camera module as add-ons
- Fully refundable until you confirm3
parts list
Build it yourself
~$260in parts
The same collar from breakout boards, a bought strap, and printed parts, at retail on today's list.
- Every part, vendor, and price
- What to print it in
- A battery setup with nothing to configure
status
Where it stands
- Prototype 01
- first GPS fix
- Firmware
- boots, loads a boundary
- Collar protocol
- drafted
- Field test
- not started
- Parts list
- published
Walk tests first, then worn by a person, then on a cow alongside a farm's existing fence. Sound first.
-
Firmware
nRF Connect SDK, low power, a geofence that never leaves an animal without a line.
-
Power and radio
Solar, LiFePO4, GNSS on a moving neck, and LTE-M with no signal.
-
Board and enclosure
A sealed top unit you can still open and repair.
Built hardware before?
OpenCollar is open to contributors and teams. Tell us what you've shipped.
FAQ
Questions, answered.
OpenCollar
Who is behind OpenCollar?
openpasture started it, contributes to it, and sells it assembled. It's an open initiative: any contributor or team can build on it, and anyone can build one.
Do I need openpasture's software?
No. Any software that speaks the protocol can run the collars. openpasture's software will be one option.
Can I buy one today?
You can reserve an assembled one. A $50 reservation fee per collar holds your place, is applied to your order when you confirm it, and is fully refundable until then. Reserve now.
Does it need cell signal?
Not to hold the fence. Boundary logic runs on the collar, which keeps its last good boundary. Signal is for new boundaries and position reports.
Which animals?
Sheep first, then cattle. The first live test is Cody's Great Pyrenees: a test of the electronics, not of livestock containment.
What license will the designs use?
Not decided yet. It will be chosen before the hardware designs are published.
1Pricing is an estimate for the assembled OpenCollar (top unit, strap, and ballast module) in US dollars. It excludes add-ons, shipping, taxes, and fees, and may change before orders are confirmed.
2The OpenCollar is a prototype. Specifications are V1 design targets, not measurements, unless marked as measured. Production and delivery timing have not been set and are subject to change.
3The reservation fee is $50 per collar, paid through Stripe. It is fully refundable at any time before you confirm an order, and applied to the purchase price when you do. A reservation is not an order and does not guarantee a price or a delivery date. See the terms.
4openpasture software features such as proposed and scheduled moves describe the design in progress. What works today is on the build log and in the docs.