The idea for this project is pretty straight forward - put a small bluetooth headset into an antique phone headset.
After scrounging the local antqiue dealers. I came across a great candelsitck headset. It was in fairly good condition (some chips on the ceramic parts, but surprinigly no rust) and it even had an external button!
Bill Bowden's Original circuit called for a LM1458 dual Op-Amp, but I used a LM324 quad Op-Amp, since that's what I had on hand. The pinout numbers are almost identical - only the power and ground pins are different.
Did you like this video? Then check out my work on The IT Life
This display was designed and built as part of the "Passive Agressive" art show.
The display uses 100 blue LEDs to display various patterens. Many large scale LED displays are multiplexed, to save power and output pins. The drawbacks are reduced light output, and the need to rely on using Persistance of Vision to simulate a frame on the board. I ended up deciding to make each 'pixel' on my display individuallty adressable. I was able to do this because the number of outputs I needed (100) was reasonable to wire, and I didn't need to acheive a very high refresh rate.
Every 2 years my local school system had an auction. This time, I picked up a large LED sign for $22.50.
The sign had a power cable, a couple of ports, and a label that read "Data Design Corp." I bought the unit assuming that I wouldn't be able to get any datasheets or manuals for it, but I did some searchign anyway. I ended up talking to a former VP of the company, who told me the company had been sold and dismanteld years ago.
At this point I had 2 options. The first was to try to figure out the connections on the controller board, and reverse engineer some kind of interface.The second option was to ditch the controller board all together and build one from scratch.
My first Balloon Camera is pretty simplistic, but surprisingly effective. I took apart an old digital camera, and created a trigger circuit out of a 555 timer, a relay, and some other components. Every couple of seconds the circuit fires, and the camera takes a picture.
I tried a handfull of different carriages, but a simple plastic box ended up working the best. Fishing line connected the balloons together, as well as served as a tether to control and retrieve the rig.
There's a lot of room for expansion in this project. In the short term I'm interested in using Eye-Fi Cards to get images live while the camera is aloft. Some sort of live video stream would be excellent as well. In the long term, I'd love to send something up even higher. I've seen a lot of really successful projects that have gotten some incredible pictures.