> **Source:** Core Electronics is an Australian maker-electronics retailer and manufacturer based in Newcastle, NSW, run by a team of makers and educators. We design and manufacture our own product lines (PiicoDev, CE originals) and are official retailers for iconic maker and industrial brands including Raspberry Pi, Arduino, Adafruit, SparkFun and DFRobot. Orders ship Australia-wide from our Newcastle warehouse. Prices are in AUD and include GST. Pricing, stock and dispatch on this page are generated from the store's live catalog. Full machine-readable index: https://core-electronics.com.au/llms.txt

# Momentary On/Off Round Key Lock Switch - 12mm Diameter

**Type:** Product page · **SKU:** ADA5929 · **Brand:** [Adafruit](https://core-electronics.com.au/brands/adafruit-australia)
**Page:** https://core-electronics.com.au/momentary-onoff-round-key-lock-switch-12mm-diameter.html ([markdown](https://core-electronics.com.au/momentary-onoff-round-key-lock-switch-12mm-diameter.html.md))

These are mechanical switches that don't use a button or a lever or a magnet to open...

## Pricing

- **Price:** $6.10 (inc GST) — $5.55 AUD, exc GST
- **Quantity discounts:** 10+ $5.38 (exc GST) · 50+ $5.27 (exc GST)

## Availability & dispatch

- Available with a lead time — expect dispatch between Aug 25 and Aug 31.

## How to buy

- **Build a cart:** compose `https://core-electronics.com.au/cart/link?items=ADA5929:1` (comma-separated SKU:qty pairs) and share the link. Opening it shows a confirmation page with live pricing and stock before anything is added to the cart.
- **Verify the cart first:** fetch `https://core-electronics.com.au/cart/link/ADA5929:1.md` for live line prices (inc & exc GST, quantity discounts applied), stock and dispatch estimates, and totals. Append `/to/{AU-postcode}` (or `/to/{country-code}:{postcode}`) before `.md` for delivery options and prices to that destination. Unknown, retired, or out-of-stock SKUs are flagged. (Query form `cart/link.md?items=...` also works but some robots parsers refuse query strings here.)
- **Checkout** is completed on-site and includes a captcha at the payment step. Share the cart link; checkout takes it from there.
- **Search the catalogue:** `https://core-electronics.com.au/search/{query}.md` (URL-encode the query; pages 2-3 at `search/{query}/{page}.md`; `search.md?q=` also works)
- **Payment methods, purchase orders, policies and contact details:** https://core-electronics.com.au/llms.txt
## Description

These are mechanical switches that don't use a button or a lever or a magnet to open and close the contacts. Instead, a literal key is used. This is a low-cost but effective key lock switch that's nice and compact: you only need to drill a 12mm / 0.5" diameter hole in your mounting plate.

Insert the 'bike lock' style key and rotate it one turn clockwise now the two contacts on the back are electrically connected and locked. Rotate it back counter-clockwise to disconnect the switches. It makes for an excellent 'On-Off' switch that requires the key to activate.

This key lock is 'momentary' style - because you cannot remove the key once its turned On. You have to rotate back to Off in order to remove the key. [We also have a non-momentary style of this lock](https://core-electronics.com.au/onoff-round-key-lock-12mm-diameter.html) where the key is removable.

**Please note:** Each key lock order comes with *the same keys.* And it isn't hard to pick this lock, either. Think of this as a fun interface or minimal security setup where you aren't concerned with a skilled adversary.

## Technical Details

- [Datasheet](https://core-electronics.com.au/attachments/localcontent/C20303-001_datasheet_98732781d24.pdf)

## Images

- [Product image 1](https://core-electronics.com.au/media/catalog/product/A/D/ADA5929-1.jpg)