Sunday, December 4, 2011

Rudder Feedback Servo

The rudder current draw information is sent back to the hand held transmitter and the pictured servo responds accordingly.

If you look closely at this picture you see that the servo glued to the stick mechanism had a small spring at attached at the end of the servo arm.

That is a tension spring used to center the stick. The servo can loosen or tighten the spring. As higher current draw numbers are received the servo pulls harder on the spring. With lower number the spring is loosened.

Ardino Ammeter

I'm on a little tangent from the original arduskipper project.

Senario: When you are sailing a real sailboat and you are the skipper you have a hand on the tiller. With that feel you can tell how much resistance the rudder producing as the boat moves through the water. To keep the boat on course sometimes you feel a considerable resistance as you push the tiller to one side.

As a radio control sailor you don't feel any of that. There is no feedback system to tell you if your just dragging your rudder sideways though the water until you see that your boat is slowing down.

So, what you see in the picture is a resistor in parallel with the servo power lines. The arduino analog input is measuring the voltage across the resistor. So basically its an ammeter measuring the servo current draw.

The relative current number is sent back to the hand held transmitter.

Sunday, July 17, 2011

Instrument Data Receiver and Display

This was a lot easier than I had imagined. I followed the Ladyada LCD tutorial and her xBee tutorial. I used the code she provided a long with the liquidcrystal library example sketch which you can find under Arduino 0022 File>Examples> LiquidCrystal>HelloWorld. To this point I can type on my computer in terminal and it will show up on the bright blue display. The connection is wireless between 2 xBees. The xBee connected to the computer used and FTDI cable and an adafruit xBee adapter. The computer just has terminal running using this tutorial. (If you want to connect to your xBee using a terminal on a Mac here's how.) The second xBee is pictured to the right.

Sunday, July 10, 2011

NewSoftSerial, Attachinterupt() and Pins 2,3

It's code time... I've been cutting and pasting code together trying to get everything to work at the same time. I'm using a em-406a GPS on the Adafruit GPS shield. I have 2 photogates that need to use the attachinterupt() function. The only digital pins that are setup on the Arduino UNO for attacheinterupt() are 2 and 3. The GPS shield uses digital 2 and 3 for GPS communication using NewSoftSerial. So I tried moving the GPS to other pins, 8 and 9 worked. Now pins 2 and 3 are free for my photogates.

Thursday, July 7, 2011

Photogate RPM Sensor Testing


I have to paddlewheel setup on the stern and plugged into the arduino UNO. I'm getting consistent analog readings of; 20-30 for OFF and 700-900 for ON. The digital cutoff point is around 400. If I take it outside ambient UV light will cause the OFF readings to jump up to 200-300 so I'll need to build a cowling to go over the whole apparatus to block out ambient light. I used the RPM photogate code available here to test the sensor's digital readings.

Wednesday, July 6, 2011

Paddle Wheel on the Stern

I have the photo interrupter all wired up. With the paddlewheel in place and painted black it works really well. right now all I get is RPMs. But I'll calibrate it with the GPS soon.

Monday, July 4, 2011

Soling 1M Sailboat - ShortCircuit


After 3 months of building I now have a sailboat. The mask is about 5ft high and the boat is 3ft long. It should be a great platform to test my electronics. It is radio controlled with 2 channels, for rudder and sail position. The sails can be pulled in or let out so that you can sail from close hauled to directly down wind just like a full sized sailboat.