# 7-segment LED-display

Hi Everyone!

So I made a little project for the company I'm working for.
So this project is just a simple counter, I've used 4 Large 7-Segment Led Displays and ofcourse 4 Sparkfun Large Digit Drivers. I've used a gyroscope as well to calculate the rate of rotation, so it counts every single time when it reaches 360 degrees. It's a counter that will be installed in a revolving door.

It's al working well but this project will be active for 3 months, non-stop!
I've calculated that this counter can run for about 2 weeks on a powerbank of 50.000mAh.

Do you guys think that the displays and arduino will keep it up for 3 months?

Thank you very much!

Yawuar

The gyroscope and Arduino together can average around 1mA of current when set up properly. The display is going to use much more energy, but perhaps you can light the display for 1 or 2 seconds every time the counter changes and leave it dark when idle. If your average current draw from the battery (display lit a small % of the time) is 10mA, a 50,000mAh battery should last 5K hours = more than six months.

How often do you actually need to read the display ?

Does the display have to be on the revolving part of the door ?

Have you considered having the system on the door send the rotation count to a remote receiver to be displayed in real time, on demand or at scheduled times ?

If the display has to be on the door have you considered displaying the count in on demand or at scheduled times ?

Have you considered alternative methods of counting the rotation of the door such as a magnet on the door and a Hall effect sensor and Arduino on the frame where it can be mains powered ?

bitbank:
The gyroscope and Arduino together can average around 1mA of current when set up properly. The display is going to use much more energy, but perhaps you can light the display for 1 or 2 seconds every time the counter changes and leave it dark when idle. If your average current draw from the battery (display lit a small % of the time) is 10mA, a 50,000mAh battery should last 5K hours = more than six months.

That's indeed a good solution but it needs to be displayed when the door is rotating, so when the door is NOT rotating it clears the segment. This still uses a lot of battery. It doesn't last longer than 2 days, in my case

Also when the door is not rotating I always need to light 1 segment, because strange enough my battery shuts itself down when the segments are cleared and that means that my Arduino shuts itself down after x seconds. Do you have any experience with this?

Yawuar:
That's indeed a good solution but it needs to be displayed when the door is rotating, so when the door is NOT rotating it clears the segment. This still uses a lot of battery. It doesn't last longer than 2 days, in my case

Also when the door is not rotating I always need to light 1 segment, because strange enough my battery shuts itself down when the segments are cleared and that means that my Arduino shuts itself down after x seconds. Do you have any experience with this?

You need to use a different type of battery pack or it will never work. It sounds like you're using a generic USB charging style pack which shuts down after 30 seconds if it doesn't sense enough current is being drawn. Your goal is to use as little energy as possible, so you'll never get more than a couple of days from a source like that. You need a "dumber" battery pack or a custom power source. Please have a look at my blog post to learn a little more about powering your Arduino from batteries: