You know how a lot of devices nowadays have a built in rechargeable battery and the user just need to plug in a micro USB to charge without having to take out the battery or swap batteries?
I want to be able to design such a charging system, with indicator light showing when battery is low/fully charged. Obviously I would need a micro USB port. But what else?
This is a project that requires microcontroller right? Please give some general basic guidance on how to do something like this and I can do more in depth research myself. Just want to know a general outline of what I need.
Depending on the parameters, it can be dead simple. There are ICs for charge control on a LiPo like the MAX1555/1551 that have a full charge indicator pin to drive the LED (one of them has that, the other has a led for something else), and you just hook up the appropriate pins to the power in.
It all depends on the type of battery you are charging. The method of establishing full charge depends on the chemistry. Some types just monitoring the voltage is O.K. others need temperature monitoring as well.
18650 isn't a specific type of lithium cell. It is a size of cell. There are three different chemistries that can be used for lithium cells, Li-ion, Li-Po, and LTO. They all have different charging characteristics.
Texas Instruments makes a great line of chips for battery chargers. They include lots of different algorithms for different types of cells. You just need to configure it for your battery type and add the high-power components that regulate the actual current going into the battery.
Search through what's available and copy the example circuit from the datasheet. That's how the professionals do it.
is this max155x something that is cost effective for production use or is it just an hobby device like Arduino?
Nobody makes chips for "hobby use", although people do use chips in boards that are intended for hobby use (like Arduino). There are consumer grade and military grade chips, with several environmental subranges.
Maxim, the company that makes the MAX1551/1555, is a multibillion $$$ international corporation. You can read about that specific chip and even order free samples here.
Several other companies make chips intended for charging Li battery chemistries. There is a very large market, as most handheld devices now use Li-based batteries.
Arduino uses the '328p, which absolutely is cost effective in production. Have you looked at the cost of, say, pro mini clones (which are '328p, plus some passives and a ~10 square cm board? They're two bucks a pop, tops. Shipped. From china.
Arduino boards (official ones anyway) cost a fortune, but most of that goes to funding Arduino, not to the hardware cost - and it shows in the clones. The hardware used on the arduino board is dirt cheap and not atypical in production.
Arduino uses the '328p, which absolutely is cost effective in production. Have you looked at the cost of, say, pro mini clones (which are '328p, plus some passives and a ~10 square cm board? They're two bucks a pop, tops. Shipped. From china.
Arduino boards (official ones anyway) cost a fortune, but most of that goes to funding Arduino, not to the hardware cost - and it shows in the clones. The hardware used on the arduino board is dirt cheap and not atypical in production.
Yeah that's what I meant by "hobby". I'm not an expert in Arduino yet. I just got a Uno starting kit.
I did take a course on microprocessor design last semester but we used Freescale HCS12, and I mainly coded in assembly. That chip is a lot smaller than the board I have in my Uno starting kit.
I talked to someone in that class and he said Arduino uses some chip that's dirt cheap (maybe it's the 328p you talked about) but it's designed for hobbiest so they added a "bunch of extra stuff." I'm not sure what he meant by this. He said if you were to make something for mass production, you would not use Arduino boards. So what is this "extra stuff" that he talked about? Sorry for the noob questions.
