Duke University Motorsports is a student group that designs and builds open wheel, single seat race cars to compete in the Formula SAE competition sponsored by the Society of Automotive Engineers. The team consists of Duke students from both Pratt and Trinity, in all classes. The purpose of the team is to provide students with a way to gain practical design and manufacturing experience in a fun and challenging setting.

Tuesday, January 31, 2012

EGT amplifier

As I mentioned before, I wanted to create a cheap, robust, small, and waterproof EGT amplifier for the car this year.  I soldered up the board about a week ago, and it works great.

For more details on the EGT amplifier circuit, click through:

The circuit is based off the AD8495 chip by Analog Devices.  This chip was a simple yet full featured chip with a small footprint, making it ideal for what I wanted the circuit to do.  The first step was to design the circuit, identify components, and draw up a schematic.
Next, the PCB design and layout.  I won't go into details here, but I managed to fit the board into a 1"x0.5" footprint.

I ordered to board via Laen's PCB batch order (http://dorkbotpdx.org/wiki/pcb_order), which I found to be amazing in every respect.  Not only are the boards top notch, the turn time is about the same as most of the other prototype fabs I've used.  And the price can't be beat - especially for small boards.  I've placed the order for the fan controller and aero controller boards with him already, and I encourage anyone that wants a PCB fabbed to try it!

After I got to board back, I soldered it up, John attached the connectors, and tested it.  There was one problem with one of the channels, an offset voltage.  Turns out one of the Vref pins had not been soldered.  Everything works great now, and the last thing we need to do it pot the board in the case.

The connectors are much bigger and heavier than the board itself...

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