Frequently Asked Questions

Purchases include $5 of prepaid API usage. Use only WENJOOP rechargeable NiMH AAA batteries with the supplied compatible charger. Every package includes one matched set of WENJOOP batteries and a charger. The shipping email includes a link to buy additional WENJOOP batteries. You need a phone hotspot or compatible 2.4 GHz Wi-Fi network without a browser sign-in page. On an iPhone, enable Maximize Compatibility for the hotspot. After the included credit is used, you need your own funded OpenAI API key.

No. Nohli does not charge a recurring subscription. Purchases include $5 of prepaid OpenAI API usage. After that, you use your own funded API key and pay OpenAI directly for usage. This is not unlimited free API access.

Allow 2 weeks for assembly, configuration, testing, and fulfillment before shipping. Carrier transit time is separate and begins after the parcel is handed to the carrier. Choosing a faster shipping service does not shorten fulfillment.

No. Nohli is sold solely as a personal study and learning aid, not for exams or graded assessments. Follow all school, testing, and institutional rules. If you are unsure whether it is permitted, assume it is not.

OpenAI generates the solution. A dedicated ESP32-S3 chip parses its LaTeX subset and draws the symbols pixel by pixel into a bitmap. It then sends finished image pages to the calculator's graph screen. The calculator itself is not running AI or doing the typesetting.

Yes. Choose EXIT to leave the program, and every standard TI-84 Plus function behaves as it normally would.

Yes. You have up to 3 replies per question. Type a reply, photograph it, or mix both approaches. Each reply includes the prior context, so you can work through a multi-part question. After those replies, start a new question.

No. The device has no answer history after you leave an answer. Take a photo of the calculator's screen if you want to keep your work.

Neat, dark handwriting on paper works best; printed text is the most reliable. Faint pencil and cramped writing are harder to read. Photographing a screen does not work because of glare and pixel patterns. Capture one question per photo, not a full page of questions.

Start with a clear, complete photo of a question on paper. Good lighting, steady positioning, and readable text help the autofocus camera capture it. AI can still make mistakes. Treat a response as help with studying, not a guaranteed answer.

Yes. CHAT uses ESP-NOW, a direct radio link for up to 4 calculators. No router, internet, pairing, account, or API usage is required. Messages can be up to 120 characters, with approximately 30 feet of range.

CHAT switches Wi-Fi off, so AI features are unavailable until you reconnect. Leaving and rejoining clears your own scrollback.

Many school, campus, hotel, and workplace networks require a browser sign-in page. The calculator has no browser, so it cannot complete that step. It is designed around a personal 2.4 GHz hotspot. It does not support 5 GHz networks.

Yes. You can change the connection details through the setup portal. Hotspot details and your OpenAI API key are separate settings.

Battery life is approximately 1.5 hours on a full charge. Actual runtime varies with cell condition and use; this is an estimate, not a guaranteed duration. The Nohli 5MP Camera Calculator uses 4 rechargeable NiMH AAA cells. Only WENJOOP NiMH AAA batteries are supported. One set and a compatible charger are included in every package; the shipping email links to additional batteries. NiMH voltage is a poor indicator of remaining charge.

The included $5 of prepaid API usage is expected to last about a month with regular, ongoing study use. This is an estimate, not a guaranteed duration; heavier or excessive use will use the credit sooner. There is no remaining-balance or usage-progress display for the included credit. When it is exhausted, the calculator will show an API error indicating insufficient funds. You can switch to your own funded OpenAI API key at any time through the setup portal. The PDF booklet explains how.

You do not need to send the calculator back. Usage on your own API key is billed by OpenAI.

No. ChatGPT subscriptions and OpenAI API billing are separate. A Plus or Pro subscription does not pay for the calculator's API requests.

Do not photograph confidential or personal information. Do not lend the calculator with your own API key loaded.

Yes. A custom prompt sets a standing preference for answer style and length. The setup portal shows when one is active. Your instruction stays in effect until you change it; leave the field blank and save to erase it and restore the default prompt. It does not override the built-in math notation rules.

You can submit written questions, not just calculations. Nohli sends them to OpenAI for a response; when an answer includes math, the dedicated chip renders the notation on the graph screen. AI can misinterpret a question or give an incorrect answer, so review the reasoning.

A custom prompt can request a different response language. Results and clarity can vary, so check the answer rather than assuming the translation or explanation is correct.

Nohli does not release its source code. Firmware work requires physical servicing rather than a customer-installed update. Contact support@nohli.com to discuss a device issue or review the Returns & Repairs policy.

No. The current product description covers the current Nohli 5MP Camera Calculator. Earlier devices do not automatically receive new firmware, and earlier orders retain the accessories and API usage included with their original purchase. Contact support@nohli.com with your purchase date and order details before assuming a feature is available on your device.

If you want to upgrade an older calculator, the $85 service fee includes updating it to the latest Nohli code available at the time of service. Shipping both ways is additional. This requires sending the device to Nohli for physical reflashing; it is not a remote upgrade or a replacement with newer hardware. Email support first to confirm your device can be serviced and review the service terms.

See the Returns & Repairs policy for eligibility and the request process. Contact support@nohli.com before sending a device back.

See demos on TikTok and YouTube. Join Discord for product news. You can request a demo by emailing support@nohli.com. Discord tickets are reserved for technical support.