Member Since: December 28, 2009

Country: United States

  • The solar cell in these pictures was from Ebay and the vendor disappeared a long time ago. The square size of that solar cell was not ideal since it gave a lip for the bird to grab onto. I was never able to find exactly what I wanted from an off the shelf product so now I have all my solar cells custom made. You can take a look at for some good solar cells though. They don't have a lot of size options but the ones I have tested are good quality

  • I would love to have the data post to twitter. The issue is that this data is for my brothers PHD studies and these academic guys guard there data closely.

  • The solar cell is connected directly to the MAX1555 with no other hardware. The diagram is posted in the data sheet for the charger and this is what I used. However soldering such a small package was difficult so I put the charger on a breakout board which Sparkfun sells. The MAX1555 has low voltage limits built in so if the solar cell isn't generating enough voltage it wont try to charge. I used a monocrystalline solar cell for this because its the only thing small enough that put out enough voltage with high enough current. I actually have a thin film solar cell which is 2.5 grams lighter but its 3 times the size which is big enough to interfere with the birds ability to regulate temperature. So I had to accept the higher weight of the smaller cell to limit the impact on the bird.

  • I forgot to mention that it is that is helping me triangulate the position. If you want an open source version you can use but it has a lot of holes in it from what I can see.

  • The database I am using is not open source. The database also triangulates wifi signals with a very high degree of precision if you are in a more urban area. I think a lot of interesting projects could be built on this and I am currently developing a few more things. The that company developed this database usually licenses it to companies like Microsoft so I am very lucky to have access to it.

  • I used the MAX1555 charger with a 5.5 volt 35 mah solar cell. Since my battery is only 50mah it gets charged pretty fast. I used the MAX1555 circuit diagram which can be found here.

  • We have several methods to catch the birds. For the chicks we climbed the tree's and take them out of the nest in order to band, weigh, and measure them before returning them to the nest. Depending on how mature the chick is we can attach a tracking device as well. For the adults we usually use a Great Horned Owl which is a natural predator to make them mad. Yes, a Great Horned Owl is illegal to own but this one had an accident with a power line so he cant be released into the wild and my brother does have the permits for him. We take the owl and put him on the ground next to the nest. Then we string up a net next to the owl similar to how you would do a volleyball net except that this one goes all the way to the ground and about 8' tall. Since the hawk is upset at the owl's presence they tend to swoop down and try to scare the owl away and get caught in the net in the process. If you are interested you can read more about the study at

  • Thanks for the comments everyone! I happen to be a pilot and I am familiar with the rule that has been put into question. I feel comfortable that I am not violating any laws by putting them on birds.
    Someone commented that this must not be rural. Actually they were deployed in Butte Valley, California which is about as rural as you can get. I timed the transmit to be at times of day that the birds are likely to be in the air which increases the odds of seeing a tower.
    The epoxy idea was great and I will give that a try.

No public wish lists :(