Privacy Policy for OhmCraft

App: OhmCraft: Electronics Tools Package name: com.mobilecastle.ohmcraft Publisher: MobileCastle (Mobile Castle) Effective date: 27 October 2026

This Privacy Policy explains what information the OhmCraft app (“OhmCraft”, “the app”, “we”, “us”) does and does not handle, and how. Please read it together with the policies of the third parties named below.

By using OhmCraft you agree to the practices described here.

Summary (plain language)

• OhmCraft has no user accounts and no sign-up. We do not ask for your name, email, phone number, or any similar personal detail.
• Your calculations stay on your device. The calculators, colour and marking codes and reference sheets all work on your phone or tablet, without a network connection. Your history, projects and notes are stored only there. MobileCastle does not operate any server that receives them.
• No camera, microphone or location. OhmCraft works only from the values you type, and asks for no camera, microphone, location, contacts or storage permission.
• OhmCraft shows ads through Google AdMob, a third party. To serve ads, AdMob may collect device information and an advertising identifier. Ads never receive your calculations.
• No purchases in this version. OhmCraft offers nothing to buy: it does not connect to Google Play Billing, and it does not ask for the billing permission. Premium features are coming soon.

The rest of this policy gives the detail behind that summary.

Information OhmCraft itself collects

OhmCraft does not collect personal data on its own servers, because MobileCastle does not run a server that receives your data. Specifically:

• No account / identity data. There is no login, so we do not collect a name, email address, password, phone number, or profile.
• No upload of calculations. The values you enter, the results, your history, projects, notes and anything you share are not copied to us.
• No analytics SDK operated by us. OhmCraft does not embed our own analytics, crash-reporting or tracking service. (Google AdMob and the other Google services described below are independent third parties with their own data handling.)

Data that stays on your device

Some information is stored locally on your phone so the app can work and remember your settings. This data is not transmitted to MobileCastle. It includes:

• History: while Settings → Save to history is on, each finished calculation: the calculator, the values and units you entered, the result and the time. Turn the switch off and new calculations are no longer kept.
• Projects: the name you give a project, its notes, the calculations you save to it and the components you add (type, value, part number, package, quantity and note).
• Your preferences: for example theme, language, units, significant digits, favourite and recently used tools, and the last values you entered in each calculator.
• A local diagnostic log: OhmCraft writes a technical log (app events and errors) to a file in the app’s own folder on your device, to help troubleshoot problems on real hardware. It never contains your calculations, inputs, results, project names or notes, and it stays on your device unless you deliberately share it.

All of it is removed when you uninstall OhmCraft. Settings → Clear history removes your history, and Clear all local data also removes projects and settings. See Data retention and deletion below.

Advertising (Google AdMob)

OhmCraft is free and supported by ads served through Google AdMob, a Google service. Ads appear as banners on the list screens (Tools, Reference, History and projects), never inside a calculator, a code picker or a diagram. There are no full-screen ads when you open the app or move between screens.

The ad requests OhmCraft sends carry no content from the app: no calculator, value, unit or result is ever passed to AdMob. To select and show ads, Google AdMob (and the Google Mobile Ads SDK included in the app) may collect and process information such as:

• a device advertising identifier (Android Advertising ID),
• device and network information (for example device type, operating-system version, general/coarse location inferred from your IP address, and similar technical data),
• ad-interaction and app-usage data related to the ads shown,
• crash and diagnostic information about the ads software itself.

Google uses this information to serve and measure ads and to help prevent fraud and abuse, in accordance with Google’s own policies. Where required by law (for example, for users in the European Economic Area, the UK and Switzerland), OhmCraft uses Google’s User Messaging Platform to show a consent form before serving personalised ads, and no ad is requested until that choice is made; you can change your choice at any time in Settings → Privacy options. You may also choose to watch a short rewarded ad to unlock one advanced calculator or one reference sheet until you close the app; this is optional.

• Google Privacy Policy: https://policies.google.com/privacy
• How Google uses information from sites or apps that use its services: https://policies.google.com/technologies/partner-sites
• AdMob / Google Ads policies: https://support.google.com/admob/answer/6128543

You can limit ad personalisation and reset your advertising ID in your device settings (Settings → Google → Ads on most Android phones).

Purchases

This version of OhmCraft offers no in-app purchases. It does not connect to Google Play Billing, it asks for no billing permission, and no part of the app can start a payment. Some tools and reference sheets are marked for a future Premium version; they show “Premium features are coming soon.” If purchases are added in a later version, this policy will be updated before that version is released.

App permissions and why they are needed

OhmCraft requests the following Android permissions. Each is used only for the feature described:

• Internet (INTERNET): to load ads. Calculations are not sent.
• Network state (ACCESS_NETWORK_STATE): to know whether the device is online before loading an ad.
• Added by the Google libraries: the advertising ID and Android’s privacy-preserving ad APIs (AD_ID, ACCESS_ADSERVICES_AD_ID, ACCESS_ADSERVICES_ATTRIBUTION, ACCESS_ADSERVICES_TOPICS) for ads; and background-work permissions (WAKE_LOCK, RECEIVE_BOOT_COMPLETED, FOREGROUND_SERVICE) that the ads library uses for its own short tasks.

OhmCraft asks for no camera, microphone, location, storage, contacts, phone or SMS permission.

Third-party services

OhmCraft relies on the following third parties. Their handling of information is governed by their own privacy policies:

When you share a result, Android’s share sheet sends it to the app you choose (for example a messaging app). What that app does with it is governed by its own privacy policy.

Children

OhmCraft is a general-audience utility and is not directed at children. We do not knowingly collect personal information from children. The app is intended for general audiences and, in line with the store listing, is not aimed at or designed to appeal to children.

Because the app shows ads, it follows Google Play’s Families and ads policies for a general-audience app. If you believe a child has used the app in a way that raises a concern, please contact us using the details below.

Data retention and deletion

Data stored locally by OhmCraft (history, projects, notes, preferences and the diagnostic log) stays on your device and is retained until you remove it. OhmCraft never deletes your data on its own: on the free tier, projects beyond the latest two are locked, not deleted.

You can delete this data at any time by:

• uninstalling the app, which removes all of its local storage, or
• using Settings → Clear history (history only; projects stay) or Clear all local data (history, projects and settings), or deleting a single history entry or project in the app.

MobileCastle does not hold a copy of this data, so there is no separate server-side deletion request to make to us.

For data processed by the third parties above (for example Google’s advertising data), please use the controls those parties provide (see their policies linked above) and your device’s Ads settings.

Security

Because OhmCraft keeps your data on your own device and does not run a MobileCastle server, your calculations, projects and notes are not exposed on our infrastructure.

No method of electronic storage or transmission is 100% secure; while we aim to protect your information, we cannot guarantee absolute security.

Changes to this policy

We may update this Privacy Policy from time to time, for example if the app adds a feature that changes how information is handled. When we do, we will update the Effective date above and post the revised policy at the URL where this policy is hosted. Significant changes may also be noted in the app or its store listing.

Contact

If you have questions about this Privacy Policy or OhmCraft’s data practices, you can contact us at:

• Email: mobilecastle.android@gmail.com
• Publisher: MobileCastle (Mobile Castle)