Car battery charger
What's this?This is simple device, that only check battery voltage and when defined voltage is reached, then unplug batter from power source. Of course, it is more "smart". And of course picture:
How it works?Basicly most of we need is already on MCU. In the begin device wait for connection with battery. When battery is correctly connected, then turn on T1, which turn on realy. So, now device charging battery. MCU track voltage on battery (use ADC on chip). When voltage on battery reach treshold value, turn off T1 -> relay turn off -> stop charging battery. At this moment all LED's will be on.
Of course, that there is signalization when battery is not connected, or when is charged. If battery is not connected LED's will blink once a time. When battery is charged, then LED's make simmilar efect which is used in mobile phones. Until battery is not connected, relay is off, so there will not be any lightning effect :) On the next image is flow chart.
DownloadAll in one. Documentation, HW design, Firmware (of course with source codes)
ConclusionWhole device should be immune to "noobs", so you can borrow it almost anybody. Of course, that today you can buy a cheap "smart charger", which detect type battery, voltage and so on. However usually there is current limit (about 1A). Also quality of AC/DC converter (especially electrolyt capacitors) is sometimes very low. Maximal current this device is only limited by relay and protective diodes.