Freeside Atlanta

Recently, we at Freeside Atlanta teamed up with the Alchemical Arts Alliance and My Inventor Club to design and build an Offroad Wheelchair so that our friend Robin can get around their events. Together, we've raised about $2,000 for the project. The design phase is usually the most difficult part of the projects, and it is often the most expensive place to make a mistake. Committing the resources to a poorly-designed project can cause the entire thing to be wasted, so we designed the Offroad Wheelchair project very carefully. We started with the constraints – We need ease of maneuverability, an ability to overcome obstacles and take fairly steep inclines, longevity to make it through events up to a week long, and recoverability in case it gets stuck. Also, biggest two constraints – Budget (~$2000) and time to prototype (2 months) From that, we landed on 3 design options – 1 – Electric motors with onboard generator for periodic battery charge 2 – Modifying an exi...

If you've been following along on my journey to learn electronics design, you'll know I've been working on a motorcycle power supply. It's getting pretty close to finished and its time to do testing. The last series of blogs were about a constant current load testing device. I needed that to test the power supply under different load conditions. This installment is about the opposite end of that spectrum, what happens when the circuit is "off". Because lots of motorcycles tend to be parked for months without being ridden I need to verify that my device does not contribute to early battery failure. To do that I need to measure the current consumed when it is plugged in but off. We are talking about very small currents though so very high precision measurements are required. Normally, you can use a digital multimeter for this purpose but for measuring small currents this not as straightforward as it seems. Ammeters are connected in series with a circuit an...

The project is finished. The units have been built and sent off for use. Much was learned. Here are some insights. First, don't design a PCB for the lowest cost. That just increases your costs later. I made the the board narrower than was convenient to save $20 and I ended up wanting to put the entire thing a case so I could mount the banana adapters off the PCB where they could be farther apart. Not necessary but preferred for me. Second, putting artwork in copper on your PCB not only works but looks great when you are finished. Take a look at the second photo below. That Freeside logo looks awesome! Third, assembly of through hole components is NOT easier than surface mount parts. It was a bit of a pain to build them all. TH components don't stay in place when you flip it over to solder.  Final PCB I used. Artwork in copper. Queued up for soldering. Delivered and installed. My lab's version with voltmeter and case. It includes a cooling...

Greetings fellow Raspberry Pi enthusiasts. I have something pretty cool to share with you today. I've been wanting to use the Raspberry Pi for a media center since I first heard about it. When Newark finally told me I could order the Pi I jumped at it chance and then promptly left town on a family vacation. My nephew Isaiah, who I met up with in Alaska while we were on vacation, discussed the media center project and how to implement it. Upon his suggestion we settled on running VLC. I had assumed we would have to get some webserver up and running and figure out how to slave VLC to our wishes but that is largely built in already. It is called the VLC Web Interface (or VLC http interface). That made this project all the more simple. Below is the process to install it. This process assumes you have a freshly flashed Raspbian Wheezy (7/15) image that has NEVER BEEN BOOTED BEFORE. This made the most sense for us as we assumed you would plop this guy down somewhere and not use it ...

I've been working on an Arduino compatible Mini USB Host board. Well, I've had it done for a while now. I've slowly been compiling a bunch of projects for it so I can give it a cool Kickstarter one of these days. To that end, I designed a dedicated shield for controlling a Roomba vacuum with a Wii remote controller so that it might make the entirety of the project more compelling. I'd already written the firmware and tested it with a chopped and spliced up cable a few months ago. It worked well for a while but one day the entire thing shot craps. My belief is that the on board voltage regulators could not handle the 16V the Roomba outputs (too much voltage to drop with an LDO without good cooling). So, for the dedicated board I decided to put a TO-220 7805 regulator with a heatsink on it. That should protect the main board from damage. I also had the idea of using optocouplers to isolate the Roomba signals from the shield. Optocouplers are ICs that contain an inte...