[Debraj] wrote in about his 2-wire serial backpack he developed for a Graphic LCD screen. It’s build on a hunk of protoboard and uses a pair of 595 shift registers to translate incoming serial data to the parallel interface which is used by the LCD screen. It takes more time to push commands this way, but the interface is still quite snappy as you can see in the clip after the jump.
The real trick here is how the hardware has been configured to get away without a third wire for latching the shift registers (if you need a primer on 595 chips check out this feature). The idea of using a latch is that all of the data can be shifted in over the serial pin before it appears on the output pins. Otherwise, the GLCD would see each bit as it shifts into the register, wreaking havoc on its communication protocol. [Debraj] gets around this by using a diode AND gate trick he learned from this other serial LCD project.
One good thing about this method is the 595 chips have a wide range of control voltage that will allow you to drive this with 3.3V or 5V microcontrollers. But you do need to implement the communication protocol and push those commands via serial. For nearly the same cost in chips something like an ATtiny2313 could be substituted to make an even simpler addressing scheme — or even switch to 1-wire protocol. But you’d then lose the wide input voltage tolerance.
Continue reading “Two-wire serial backpack for GLCD screens”
Here’s another Flora Arduino based project from [Becky Stern]. It’s a backpack with brake lights and turn signals for use when motorcycling, but it should work just as well for bicyclists. From this view the project looks pretty normal, but things get downright crazy when she decided to use the WS2801 pixels for the LEDs. Sure they take all the work out of driving an array of LEDs, and they offer full color and dimming levels. But when you see the bulk of cabling and PCBs this adds to the project (shown in the video after the break) we think you’ll agree that this was an interesting choice.
That issue aside the project is a lot of fun. The system doesn’t patch into the motorcycle’s electronics. Instead, it uses an accelerometer to detect when the brakes are applied and light the LEDs according. The turn signals are switched with an RF remote control that can be mounted on the handlebars.
Anyone looking to hack outerwear with electronics can learn form the fabrication techniques used here. [Becky] details how to make holes in the bag and sew parts to them, as well as using Sugru to waterproof vulnerable components.
Continue reading “Brake Light Backpack overpowered with LED pixels”
Back in the 1980’s there was a movie cliché that the person with the largest boombox on their shoulder was always the coolest. It’s obvious to us that [Tim Gremalm] thinks that’s silly. Why be uncomfortable carrying something like that on your shoulder when you can strap a much larger object to your back? He’s working on a mammoth speaker enclosure which can be carried around, but he needed a set of backpack straps to make it happen.
This thing is going to be adding some serious weight to his body, so he also whipped up the padded waist belt seen above. For fabric he reused an Ikea couch cover. The material is made to survive a lot of pulling and stretching. For padding he used what he calls ‘floor mop’. It looks like it might be microfiber mop cloth be we can’t really be sure. With ten layers of the mop encased in the couch cover he finish off each strap by sewing it to some nylon webbing.
After the break you can see a picture of [Tim] modelling the huge polycarbonate speaker enclosure for which these backpack and waist straps were made. This project has many posts associated with it so if you’re interested in seeing more you can use this project tag link.
Continue reading “Fabricating your own backpack straps for unorthodox uses”
We hope you’ve already got parts on hand for your holiday projects because shipping might be a little slow at this time of year. But if you’ve got a bag and some unused EL wire here’s a one-day project you should try. Make yourself a Tron-inspired shoulder bag, or backpack.
On the right, [PT] is doing fantastic job of modeling with his electroluminescent offering. This is another Adafruit offering that holds your hand each step of the way from designing, to sewing, to wiring it up. This will go great with that glowing unitard he’s been working on.
[Alan Yates] has also done a spectacular job with his Tron backpack seen on the left. He picked up his EL wire on clearance at a place called “big-W” after Christmas last year. They were selling 3 meter segments (each with their own inverter) for just $3. We’re happy he got a deal and even more pleased that he found a use for it.
[Max Weisel] recently created a Peltier-based cooling/heating system that fits into a backpack. The system uses two Peltier units, each running at 91.2 watts, with computer heat sinks mounted on one side of the unit to dissipate the excessive amounts of heat generated. While he was originally trying to build a cooling backpack, the use of the Peltier units meant that the cool side would become warm when the direction of current was switched, meaning that the backpack could become a heating backpack with the flip of a switch. In order to power the two Peltier units, he uses two 12v motorcycle batteries, weighing in at around 5 pounds each. While this backpack might be a little heavy for your back, it looks promising for anyone who needs to keep things cool (or warm) on the go.