Need Help with a Simple Timer Circuit

Posted: November 8, 2018 in Call for Help, Tasca

Are you an electronic wizard looking to solve a small problem in your sleep? Well, this might be just such a project for you. I need help solving a problem for a product we make under our “Tasca” brand.

We are in need of a basic, robust circuit design we can make (potentially using through-hole devices) to create a simple timer as shown below. We have been looking for such a device for some time, and have had no luck. Available timers we’ve found all include features and programming capability that is not desirable for the application. Others utilize software driven logic that is more than we need, and not reliable enough for our requirement.

Here is the schematic design we are attempting to achieve:


We do not need any memory function or other logical operating features. This is for a product that will see rough service operated by individuals with minimal training, who will only operate the product occasionally, on an as-needed basis. For this reason, the timer display simply needs to work with no operator input, other than in response to activating the light itself (identified in the diagram as “14V Load”. Additionally, we need this product to operate without any volatile logic components that could fail to operate due to power loss or battery failure. The CR2032 battery should be replaceable on the circuit board by qualified personnel only (not user accessible) so needs to have a long service life (2+ years).

Operationally, all we need is for a timer to wake up and display how many seconds the light has been on, in seconds, from 0 up to 999s – then turn off when the light is turned off, resetting to 0. That simple. No fancy settings, optional configurations, re-set button, memory recall, etc… etc… etc… Just a timer display – end of specification.

I would like a circuit design we can make up in-house as we need them, using through-hole devices we can purchase to have on hand, to be hand assembled on prototype boards that we will have made, allowing us the flexibility of changing the board configuration as product configurations change, and to fit available space inside the devices it will be used on. Alternatively, if someone wishes to provide a completed timer as shown, using SMD devices, in a very compact form, on a low production run basis (25 at a time), we are open to that as well.

The application is for a portable cure light system that has very limited internal space, made to order to meet unique specifications to suit customer requirements, which include military and marine/automotive industry repair applications.

Anyone interested in helping with this, please contact me to discuss fees and costs involved (we do not expect this to be a freebie) and time to complete the work required.

The need is immediate, so please don’t hesitate to call or reach out with a solution.



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