I pulled apart my car’s start/stop button today to redo some chipping paint that was bothering me. Naturally, I couldn’t stop at only the cosmetic plastic once I saw that there was a small PCB inside. There are two interesting things about this picture. First, look at the PCB: there are some electronics (and more than just regulators to drive the LED), an LED to illuminate the button, and nothing else. Continue reading
Being out in LA, I recently bought a car – I ended up with a used BMW. It’s pretty sweet, but I’m me so obviously I’ve moded just about everything I can without actually buying parts. Mostly that means software mods – windows up on key fob lock press, that sort of thing. But I’ve also been trying to mod bluetooth into it, and only recently had success. Tonight I got curious and took the module which controls bluetooth and USB aux-in apart (referred to as a MULF2 High Basis, it lives in the trunk and connects to a USB plug in the center console). Here’s what I found. Continue reading
I’ve had this traffic light sitting in the corner of our apartment for a while now – I’ve been meaning to do a traffic light project for a long time and I finally got one as a gift, so naturally it came out to Cali with me when I moved. But until now it’s just sat nicely in the corner, all lights on when plugged in and all lights off when not. Well, I just got my Bluetooth Low Energy shield from Seeed Studio in the other day, so naturally it was time for that to change. Continue reading
So I mentioned in the UART Level Shifter post that a SPI Level shifter using the same ON Semi part would make a lot of sense. So I made one. It’s out for fabrication at OSH Park now, the third project in two days that I’ve sent to them. Hopefully they all make the cut for the panel that’s supposed to go out on the 19th. I’ll let you know how they go once I get them back! Check out the Github repo here.
Level shifters are a fact of life for hobbyists working with different logic voltages in the same system. Many systems run on 3.3V, while many others run on 5V, so interfacing 3.3V logic with 5V logic is a very common problem. Lots of solutions exist. Continue reading
I just received from Sparkfun a few RFM12B wireless modules to experiment with. They’re great little things – you get a FIFO in, a FIFO out, all the RF stuff is taken care of, and you have super flexibility with all the network layers above that. The best part is, the relatively low complexity compared to something like a ZigBee means both that there’s no extraneous fluff when your application doesn’t need it, and the cost is just right at $7/module in low quantities. But annoyingly, they can be had in a SMD module with 2mm pin pitch – not very 100mil breadboard friendly. Not wanting to deal with that. I whipped up a basic passive breakout board to have on hand. Inevitably, this will see updates as I do things like add regulators and level shifters for particular projects. For now, it just makes breadboarding easy. To get the files, head over to the Github repository at https://github.com/alexwhittemore/RFM12B-Breakout. I’ve ordered 6 from OSHPark, I’ll report back in a couple weeks how they turned out.
If you’re designing a data acquisition system with Wheatstone bridge-based sensors to be measured, the easiest (if not cheapest) solution comes from National Instruments in the form of the NI 9237 CompactDAQ module. Boston University’s Rocket Team (http://www.bu.edu/rocket) will be using this guy in upcoming tests this academic year to make sure our static motor data is as precise and repeatable as possible. Continue reading