Battery Tester and pinball

2016-01-20 21:17  
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This article is the interpretation of the battery meter principle of pinball machines. Please note that if your battery 4.21 v or when new and then all the leds will stay away. In most cases, the new battery is not always to their specified voltage - is usually a small voltage drop. The circuit design into a small box, then install to your backbox (exact choice location you). Only 3 wires are required - one for the battery v, and a microprocessor for 5 v supply from the board or the power supply and a common return to the ground. This circuit is designed for 4.5 volt battery cells (3 x 1.5 v). This circuit to level leadership instructions using 3 - a green (good), an amber/yellow (center) and a flashing red LED indicates low battery power 3.2 v or less. I think that a drop of 1.3-1.5 v should enough warning - I can't on the same day of the open circuit voltage of the CMOS memory backup WPC games because ASIC, so, I have here for you to see. Theory of operation 3 battery voltage comparator to compare input reference voltage provided by the 3 three dividers (see diagram), 3 comparator direct drive LED the sinking of the ground (internal). On the rise, the green LED will always indicate good battery. As the battery voltage drops, the amber LED will light, followed by red flashing LED, LED in front of continue, until the all leds are lit up. I designed the circuit to reduce the number of components in this way, make it easier for construction. If you want to modify the circuit, the LED will be extinguished one by one the other, I suggest that you use  74 HC03  four nand gate and LED current is output to the water tank leakage, input of the comparator is who is to switch to the next year in sequence so as to put before the door closed, I will consider the detail sketch here but I don't have the IC convenient time) incorporated into the design. The battery need the following tools: a soldering iron, a side cutter, and a little flat blade screwdriver, or 0 a digital voltmeter (DVM) or oscilliscope.
 

vbat1 Battery Meter for Pinball Machines

[Power inputs and decoupling]

vbat2 Battery Meter for Pinball Machines

[Comparators and LED drive]

vbat3 Battery Meter for Pinball Machines

 

vbat4 Battery Meter for Pinball Machines