Current Sensors

[Al Skierkiewicz]

A number of years ago, Team 111 designed a current monitor system using the MAX4172 Maxim chip and a Motorola micro. This chip is designed to monitor charge current in laptop computer power supplies. What makes it ideal is it designed for a single ended power supply and is scalable for current. We used it with modified 1' sections of #10 wire and monitored supply current to the Victors feeding our high current motors. The #10 had a small guage wire attached to each end that to the Maxim chip. The output was then fed to the micro D?A input and the data was then ported to the RC where it in turn was sent back to the OI. Another device at the OI then ported the dashboard data to a color Palm Pilot and would signal the driver when the motors were in normal or high current by changing the color on the Palm readout. By saving the data along with the time ticks from the dashboard and RC battery voltage monitor, we were able to analyze a direct relationship between high current draw and low battery voltage. And the data proved very important in electrical design in the years since. We used a portable version for a while to help analyze other robots. One of the more telling tales came when testing the Thunder Chicken multi-motor transmission. We were able to determine a failed motor in one of their systems.
I will try and find the schematic for this system.