Recent content by jsfetzik

I have looked into using Teensy and other MCU devices as a USB to DMX controller and in general found it wasn't worth doing. By "in general" I mean if you are looking to just control existing DMX devices from a PC. It is quicker and probably cheaper to buy a decent off the shelf solution, like...

This is likely the problem. 2.1A is not enough to drive 400+ LEDs. 50 LEDs at full brightness white can draw as much as 2A, depending on the LEDs used.

We used DokuWiki internally within my work group for about 5 years. We have not used it for a couple of years now, due to various internal corporate changes. I also hosted a MediaWiki site for an Eve Online guild for a few years. DokuWiki was very easy to set up and easy to use. It didn't have...

Well that's another piece I won't have to design and build. :D

Thanks for the "Cyber Monday" sale. I got tied up all day Friday forgot to order before going to bed oh so very late. :)

Lots of good discussion, but i figured I would add my current audio desires to the list. My use is to add sound to Sci-Fi props, such as blaster pistols and light sabers. So I need the small size to fit inside the props. Sound quality is not a big deal, because the speakers are pretty much...

I would say that would be a great idea. Many people just don't realize what real world conditions can do to your project that worked perfectly on your desk/workbench. Knowing anything about harsh/noisy environments ahead of time at least gives you a head start in handling what they can throw at...

As Paul said the problems will not be fixed without some hardware changes. The environment this is being used in is "electrically noisy"(EMI, static, etc.). Given this better description of the environment and seeing the pictures it looks to me like there are a few things missing. First, what...

I am using Teensy because of the big feature list, in a small size, at a good price. For my current project I need at least 7 PWM outputs, the ability to run off a single 3.7V Li-Po battery and it has to fit into a 1"-1.25" diameter tube. The Teensy family fits the bill perfectly. My application...

IIRC serial.read returns a byte, not a char. So change the type of cmd to byte and try changing the print line to the following to cast the ASCII byte back to a character. Serial.print((char)cmd);

If you are running for only 3 hours you should be able to power things without a problem. A set of plain old generic AA batteries fresh from the package should provide 400mAh or more. So even if your circuit draws 100mA on average you can run for 4+ hours. With better batteries such as good...

The diode would be in series between the power supply and the relay coil. The reasoning for this is to prevent reverse flow of current when you turn the relay off. When energized that coil has stored energy in it. When you turn off the transistor that stored energy will get converted back into...

Off the top of my head I think the SD card spec says it should be 0.5mA in standby and 45mA max during 50MHz read or write. At 25MHz current draw is about half that. I have heard real world numbers of as high as 80mA during a read/write. Low quality cards probably. So how much the current draw...

For rule of thumb you can take the UART bps, divide by ten, for start/stop overhead, to get characters per second. Divide one by the result and you get the time per character. Multiple by the UART buffer size to get the max time you have. For example 57600 / 10 = 5760 characters per second 1...

I would suggest some isolation of the power supply to the relay. Minimally a diode, possibly a cap as well. While the coil may not use much current once latched, it can draw a lot more when it is first engaged. Plus you can also see reverse current, particularly when the relay is shut off.