SUNDAR update

Posted on December 2, 2013 by Skye Sweeney

It has been a while since I last posted and a lot has happened in the meantime. I will not bore you with Thanksgiving celebrations, but I will let you know the last few weekends have not been my own. I have been technical judging at various FIRST LEGO League (FLL) tournaments. These are tiring days. We start early, work hard with the students and get home late. I am physically tired, mentally exhausted and in no mood to work on electronic projects. Continue reading →

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FIRST LEGO League mentor

Posted on November 13, 2013 by Skye Sweeney

I have been very involved with FIRST LEGO League (FLL) for many years. I started as a coach, then did some special projects for the organization, and now act as a mentor for coaches around the country. This year I took on a local team to help them implement an invention they dreamed up as part of the research project they do besides building their robot. Continue reading →

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SUNDAR upgrade parts

Posted on October 31, 2013 by Skye Sweeney

I just got in the mail today the parts I ordered for the SUNDAR upgrade. I am a very happy camper. The stepper motor I purchased was a little ‘5V’ 200 step unit from Pololu. To this I added a low voltage motor controller and some output collars to make assembly simpler.

This stuff is ridiculously small. The motor is about 3/4 inch square and an inch long without the shaft. The motor controller is about 1 inch by 1/2 inch in size.

The stepper motor looks gorgeous. The shaft has a very nice snap at each detente. The front mounting face is a high polish with threaded holes. Right now the trick-or-treat kids are interrupting me every few minutes so I can’t get to the lab to test this out. Perhaps I could come down with a sudden case of Beriberi and skip work tomorrow?

 

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SUNDAR upgrades

Posted on October 29, 2013 by Skye Sweeney

After I have proven to myself that I have a good chance to get a solar compass to work for AVC, I started to look at improvements.

The first would have to be miniaturization. Currently the system is very bulky, finicky, and heavy. There is no way this would survive being mounted to an RC car. Continue reading →

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It works (SUNDAR)

Posted on October 26, 2013 by Skye Sweeney

I finally got some free time at the same time the sun was visible to take the SUNDAR outside. I took it out on my deck and hoping for the best, turned it on. Here is an output from the SUNDAR:

Sundar output

The blue trace are the pulses from the optical interrupter on the radar head. The yellow trace is the output from the photo diode. It obviously shows a significant peak as the sensor points at the sun. In fact it saturates the sensor even with a very low gain. I will need to add a neutral density filter to the device to prevent saturation.

What is not seen here is that if I rotated the device, the relative position of the yellow peak to the blue sync pulses. What is also not seen is that the output of the Arduino provides the relative azimuth.

It did see a few strange software bugs that I need to clean up, but I think the basic premise will work. Now I need to miniaturize the whole system.

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Out of town

Posted on October 21, 2013 by Skye Sweeney

I got called out of town for a week. Did not get a chance to start testing the SUNDAR. And now by the time I get home it is dark. Testing will have to wait till the weekend. Grrrrr.

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A hope for the SUNDAR

Posted on October 3, 2013 by Skye Sweeney

Last night I started end to end testing of my solar compass. The pre-amp, amplifier, AGC, and digitizer circuits all seem to work. The code for computing Azimuth also seems to work in a lab environment. So far so good. Hope to get out this weekend for field trials.

HOPE LOST: It rained all weekend. Spent it working on a simulation of various AVC algorithms.

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SUNDAR Update

Posted on October 1, 2013 by Skye Sweeney

After etching the pre-amp board and populating it with parts, my quick test showed that the device did not work. No smoke, but no amplification either. And then some personal issues came up that I had to take care of. Over the last few nights I got some time to start debugging and quickly found that I had usd a 1K resistor and not a 10K resistor for the opamp feedback resistor. Quick fix and the pre amp started to work. Continue reading →

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Dilbert moment

Posted on September 23, 2013 by Skye Sweeney

I have been involved with a simple project at work to build 55 field re-programmers for a product we make. The case has a few bits of electronics in it including a 50 cent micro, and a $1 voltage converter. Rather than design a small circuit board for the micro and regulator, the company elected to buy the parts in “development kit” form.

Imagine their surprise when TI got an order for 55 MSP430 and 55 12V to 3.3V regulator development kits . Who in their right minds orders 55 development kits? Who in their right minds then spends a few hours opening up all the boxes to extract the tiny circuit boards and then throwing away the rest? I guess I do.

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uBlock LEA-6H GPS arrived!

Posted on September 21, 2013 by Skye Sweeney

I placed an order for a uBlock LEA-6H GPS from Hobby King some time ago only to find out it was back ordered. I got my email on a list to let me know when they came in. A few months went by and I went back to the website to find out that the GPS I was interested in was discontinued and that Hobby King did not think it important to let me know that a new version was out. In any case I place my order and then was told that the wait time would be up to 6 weeks.

But a few days ago, the device arrived from Hong Kong is a very lightly padded envelope. I was afraid it might have been damaged, but it looked in good shape. Today I plugged it in using its USB interface and got the device drivers installed. Brought up Putty to listen to the communications and could see NMEA strings flying by. And then I was shocked to see the device get a lock. This is the first GPS device ever to lock next to my computers and I have had tested high end devices. I am pretty impressed.

Next step will be to collect a bunch of data outside from my reference point and see how it looks.

Posted in AVC, uBlock LEA-6H | 2 Comments