LEGO® RCX Brick Rechargeable Battery Tester

  The ciruit on this page is for a rechargeable battery tester using a LEGO® RCX Brick to gather voltage verses time data and then upload the data to a PC using the ROBOLAB Software. The Data can then be exported to a spreadsheet for further analysis and comparison.

  The following schematic is for the battery tester circuit. One half of an LM 358 OPAMP is used as a voltage follower to feed the voltage data to the RCX® Brick' input and the other is used as a voltage comparator to disconnect the load from the battery when the voltage across the cell falls to 1 volt.

  A relay is used to disconnect the load resistance so that the battery can not be drained completely.

Battery testing Circuit

  The following images are Screen shots of the set-up of the LEGO® RCX Brick taken from the ROBOLAB program. Also shown is a spread sheet graph of the data for 5 D size Nickle Cadmium Batteries.

Screen Shot Of The LEGO® RCX Brick Program.

Screen Shot Of The LEGO® ROBOLAB Data Display Graph.

External Spread Sheet Graph Comparing The 5 Cells Tested.

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Please Read Before Using These Circuit Ideas

  The explanations for the circuits on these pages cannot hope to cover every situation on every layout. For this reason be prepared to do some experimenting to get the results you want. This is especially true of circuits such as the "Across Track Infrared Detection" circuits and any other circuit that relies on other than direct electronic inputs, such as switches.

  If you use any of these circuit ideas, ask your parts supplier for a copy of the manufacturers data sheets for any components that you have not used before. These sheets contain a wealth of data and circuit design information that no electronic or print article could approach and will save time and perhaps damage to the components themselves. These data sheets can often be found on the web site of the device manufacturers.

  Although the circuits are functional the pages are not meant to be full descriptions of each circuit but rather as guides for adapting them for use by others. If you have any questions or comments please send them to the email address on the Circuit Index page.

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