Battery Power

So I am using a Teensy to run a nice little gadget that I can record the date, price for fuel, amount of fuel and then the miles traveled on said fuel. It uses a keypad, a 128x32 OLED display and an SD card: the OLED requires 3.3V and the SD module requires 5V.

Could you make any suggestions as to how I can battery power my device please?

Ideally I would like to only be using one AA as the key pad is 51x57mm and I dont want to make the unit too deep really, but I guess I could use two.

I fill up with fuel once a week and would only be switching this on when I fill up for about a minute each time.

If there is anything else I need to provide let me know.

I have read up and a ~1V to 5V dc boost converter looks like a good option but I am not too sure whether the 100mA output that these commonly put out is enough.

Please help. Thanks.

Note. I am in the UK so any US products would cost too much to ship for their value probably.

For example would this be a good option:

lI've been powering a nano and oled with 3 AAA batteries in a neat case from here https://www.componentshop.co.uk/battery-holder-for-3-aaa-batteries-side-by-side-with-cover-and-switch-wire-connects.html . I hot glue them to the back of their RX2008 boxes, and the overlap is where the switch is. However, space is less restricted with the RX 2010 case with the 3 AA cell battery holder glued on the back. Nmh/nicads will last longer than single use cells, since the discharge curve is much flatter, but for your intermittant use, any should last long enough.

To avoid mixing too many different voltages, consider getting a 3.3volt SD card module. for example:

https://www.ebay.com/itm/9-Pin-Micro-SD-TF-Card-Reader-Read-Write-Module-Storage-Memory-Board-Arduino/183930384888

If you are switching the whole thing off when not in use, the power requirements of the devices are not so critical. It is more complex when you want the MCU to go into sleep mode, then you have to ensure that peripherals are switched off and there is sufficient power ready for when the device wakes.

Your car does not have a power output? Plug the device in and update data?

DrDaveyG:
So I am using a Teensy to run a nice little gadget that I can record the date, price for fuel, amount of fuel and then the miles travelled on said fuel. It uses a keypad, a 128x32 OLED display and an SD card: the OLED requires 3.3V and the SD module requires 5V.

I should imagine a $20 smartphone with the right app should do this quite well. :roll_eyes:

I should imagine I am trying to programme a microcontroller and not make an app :o Not very helpful at all.

Well, an early 'not so smart' phone has a) nice case b) battery, c) display, d)keypad e)charge facility f) space for a uP. What's not to like?