The Need
In an observant Jewish home, the day's schedule — dawn, the times for reading the Shema, sunset, candle lighting, and the Sabbath's end — is essential daily information. The existing solutions are an annual printed calendar or a phone app, and neither is ideal: the calendar means looking times up by hand every day, and the phone is unwelcome in such a home on the Sabbath itself. The client asked for a wall clock that displays all of the day's times — and depends on nothing external: no internet, no updates, no server.
The Engineering Solution
The heart of the product is algorithmic: we implemented a full astronomical sunrise-and-sunset calculation inside the device, based on NOAA formulas, from which all the halachic times are derived for any date and any location — indefinitely far into the future. The device needs no network at all: a precise real-time clock with backup keeps the date, and the calculation runs locally every morning. That is a fundamental specification decision — the kind we describe in new product development — and it makes the product dependable for decades without maintenance. It also drove the choice of processor in the electronics development: a modest microcontroller is enough, provided its floating-point math is accurate.
Readability Before Everything
The display was chosen with care: an e-ink screen that looks like printed paper, readable from any angle with no self-illumination — suited both to Sabbath observance and to home aesthetics. The firmware timing was tuned so the screen refreshes once a day at a minuscule power draw, part of the hardware-software interface work covered in embedded software. Planned next steps include city selection from a built-in list and adapting the time customs for different communities — all, of course, without giving up full independence from the network. The product is a natural fit for the specialized practice of kosher product development.
Development Scope
- Algorithms: full astronomical calculation and derivation of the halachic times.
- Electronics: an e-ink display, a backed-up clock, and minimal power consumption.
- Software: an embedded Hebrew calendar with a fully Hebrew display.
Takeaway
Sometimes the most advanced requirement is independence: a product that computes everything itself, with no cloud and no updates, is the only product you can promise will still work decades from now.
Have an idea for a product that has to just work? Contact Projects House through the form and we will help you build it.