<html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"></head><body><div>It's pretty straightforward. You can do this with just an Arduino and one of the cheapo L298N H-bridge boards on ebay. I did it very crudely and easily, and ended up with poor control below about 30% RPM (on my particular indicator), but totally smooth response above that. Another fellow I know adapted a sine wave approach that used the Arduino's PWM channels, which gave good control all the way down to 0.</div><div><br></div><div>Check out the overhaul manual for your indicators. You're basically building a brushless speed controller.</div><div><br></div><div>Matt</div><div><br></div><div><br></div><div><br></div><div id="composer_signature"><div style="font-size:85%;color:#575757">Sent from my Sprint Samsung Galaxy S® 6.</div></div><div style="font-size:100%;color:#000000"><!-- originalMessage --><div>-------- Original message --------</div><div>From: "David C. Allen" <dca911t@gmail.com> </div><div>Date: 8/7/2017 1:04 PM (GMT-06:00) </div><div>To: Simulator Cockpit Builder's List <simpits-tech@simpits.org> </div><div>Subject: [simpits-tech] N1 & N2 Gauges </div><div><br></div></div><div dir="ltr"><div><div><div><div><div><div><div><div><div>Hello<br></div>I was wondering if anyone has used a Arduino to get the N1 & N2 gauges operational?<br><br></div>From the information I have found there is a 3 phase generator for the N1 & N2 mounted on the engine. The gauges have a 3 phase motor connected to a flux coupling (like is used in a mechanical speedometer) to drive the pointer. Once the engine is operating the N1 & N2 are self powered.<br><br></div>I found a chart that lists the generator RPM vs Indicator % RPM<br><br></div>0 gen = 0 %RPM<br>840 gen = 20 %RPM<br>2520 gen = 60 %RPM<br>4200 gen = 100 %RPM<br><br></div>So a question on frequency of the generator, would vary with generator RPM <br><br></div>Looking at one leg of the generator <br><br>0 gen = 0 Hz = 0 %RPM<br>840 gen = 14 Hz = 20 %RPM<br>2520 gen = 42 Hz = 60 %RPM<br>4200 gen = 70 Hz = 100 %RPM<br><br></div>Just looking for ideas<br><br></div>David<br></div>N9070U 737-222<br></div>
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