Member Since: December 19, 2010

Country: United States

  • Don’t forget to add an SSR and a programmable PID controller so you can have a nice profile. (I use parts from a Sanguinololu and control it using gcode sent from pronterface.)

  • I just pulled mine from my junk desk. One of the LEDs was broken and I was determined to fix it. Broke out my multimeter, found that there was positive voltage getting to the right pin on the LED. Found no voltage across the LED (so probably not a bad LED). I thought the ground side of the LED wasn’t making good contact with the ground plane. So I cranked up my soldering iron a bit to “ground plane temperature”, added a bit of flux, scraped some of the ground plane back to make sure it gets a good connection, and went at it. The connection I made was fine. Still no go. Then I shorted the ground LED wire to the ground pin. Works fine. Examined the traces on the PCB more closely. There’s PCB error on mine! The ground plane goes half way, but fails to connect to the rest! So I just added a bodge wire from ground to the ground LED pin. (A broken ground plane didn’t do anything in their QR department?) The board is labelled Simon and the date is 5/3/10. Works fine now, but definitely a learning experience in trusting Sparkfun’s iffy PCB layouts.

  • If you put a directional, I wouldn’t TX. You might (almost for sure) go above the FCC EIRP limit for Part 15 devices.

  • I think the ideal setup for these radios is to have two pairs on each side. TX and RX on one side, TX and RX on the other side. (And use two slightly different frequencies for upstream/downstream feeds.) The reason for this is, if you connect a 1W transmitter to a yagi, it will almost certainly be illegal by FCC standards. (Unless you attenuate the heck out of it or if you turn down the power to a trickle.) BUT, using a yagi for RX is not illegal, you can have as powerful as a receiver as you want. (AFAIK. IANARFE and certainly not a lawyer!) So the ideal setup is to have (omni for both TX) and (yagi for both RX). The curvature of the earth really becomes a factor when you start simulating with programs such as Radio Mobile. (It has a Radio Link simulation feature I am playing with.) It takes a bit of setup just to get a small example going, so read the tutorials. To overcome the curvature of the earth, you almost for sure will want to have one side on a mountain top. (If you have it in the simulation program, you can see how this helps.) On my playing with the software, I put omni TX w/7db gain in Indian Springs, NV and put a RX w/25db yagi on a hill 17km away. (Both sides were 1m off the ground.) Supposedly, I should be able to get 23dB over the noise with a setup like this. (TX power = 1W, EIRP = 2W.) This was only a simulation.

    About the original post: If you already have two units and force one to be TX, one to be RX, try attaching a 20dB+ yagi to your RX side and see if you can go past 5mi.

  • “Simplified SD Specifications” is a bad link.

  • Do you have any good sources on where to have stencils made? Buying a $10,000 laser cutter for a few projects seems like a waste. Does Sparkfun have a laser cutting service?

  • Wow, you used phillips screws for the front panel? And she didn’t just unscrew them? You’d have to use some foreign security bit screws or maybe super glue if the person you gave it to was a geek.

  • 10,000 quiz takers, 100,000 people trying to take it though.

  • Host a server on an alternate data center with an alternate IP. Give a DNS pointer from to this new IP. (82347 is a randomly picked number) When the first 1,500 people get to the page, redirect them to the other site. Then put everyone else into some sort of holding pattern. (Sorry, try again.) That way, the selected first 1,500 people will get to have an actual chance at taking the quiz with decent latency. If they fail the quiz and there is still money left to be given out, have the quiz server communicate to the main WWW server to let a few more people in. The quiz server will be unknown to anyone not given access. (For even more security, pass a token from one server to the other and require it on the URL.) Separating the server that takes all the DoS hits/etc and the actual servers used to take the quizes is a GOOD thing. Maybe next year. (I got $0 out of this because the site was completely useless all day.)

No public wish lists :(