Many aging Ford Focus vehicles have this charming tendency to lock up the ignition switch making it impossible to start your vehicle no matter how hard you beat the steering column with your head/fist. There are no warning signs that the ignition switch is about to fail.
Pretty frustrating that Ford hasn't issued a recall or even put out a notice. What would happen if someone pulled over to attend to a baby while driving in -40°C Canadian weather? One minute everything is totally fine and the next minute, you could be trying to flag down help on the highway and keep a baby warm at the same time. Sub-optimal.
Anyway.... here are some tips for replacing it yourself for cheap.
Long story short, the UM232H can easily be turned into a 7.5 Msps Logic Analyzer (async 245 mode) with some added software (in progress).
What is a Logic Analyzer? No, it doesn't explode when an anti-vaxer blows into it. Nor does it help explain why the opposite sex is clearly crazier than you. A logic analyzer simply allows you to capture, display and decode digital signals. Very helpful when debugging your robot army, or making little Arduino circuits work.
Some friends and I wanted to build a really fast FPGA based Logic Analyzer (LA), but we all have lives (unfortunately?) and many other side projects. During the early design phase, we selected the FTDI FT232H USB IC as the link to a computer. After reading through the datasheet a bit, I noticed that it may be possible to have that single IC function as a low speed logic analyzer. Even better, FTDI sells a small $25 dev board for the FT232H called the UM232H that plugs directly into a breadboard and saves us work (other dev boards 1, 2). When it became clear that the group didn't have the time required to bring an epic FPGA design to life, we decided to try wrangling the UM232H into a cheap LA. The idea was to have the UM232H sample its 8 input pins as fast as possible and dump the data upstream to a computer for analysis and storage. This idea isn't novel as there are many other cheap analyzers (read: Saleae clones) that do that exact thing with a Cypress FX2 IC. However, the FTDI IC is 2-3 times cheaper than the more capable Cypress IC, and I was looking to learn something new anyway.
The diagram below shows the wiring required to make the UM232H work as a cheap LA.
Pretty happy to have my first Instructable chosen to be featured :)
It's just shy of 6000 views at time of writing and has some promising comments from people excited to try it out.
You can check it out here if you like, but it is very similar to what is already on the blog.
Feel free to drop me a line if you ever try it.
This post will give you some code to generate high frequency square waves for IR sensors as well as explain how the Fast PWM mode works for Arduino.
I needed to interface with some IR sensors when designing the high tech mini golf hole and had to generate a 38 kHz square wave to drive the infrared LED so that it could be seen by the TSOP4838 IR receivers.
The basic Arduino analogWrite function is limited to less than 1 kHz (depending on your board), so you need to directly access one of the other on board Timer/PWM modules. The Arduino Uno (ATmega328) has 3 timer/counters:
- Timer/Counter0: 8 bit, already used by Arduino for timing functions like millis() and delay().
- Timer/Counter1: 16 bit, which is more than I need for this, so I'd rather save it for something else.
- Timer/Counter2: 8 bit, fits my needs perfectly.
Here are some basic instructions on how to build a $2 compost thermometer using readily available supplies. It looks crappy (in a good rustic kind of way), but works great and uses few materials.
You really don't need to read this... I like this design because it's pretty functional, reaches the correct temperature faster, and looks cool, but you could just duct tape everything together in a minute and see if it works for you first.
I chose to use a dry fallen tree branch because they are super abundant, eco friendly, and have reasonably low thermal conductivity. This is good because you don't want your stick to be conducting much heat to or from the thermometer probe tip as this will increase the amount of time it takes to get a stable reading. My first attempt took me a minute to duct tape the probe to a piece of steel rebar, but I found that the rebar was not only cooling down my probe, but also my Read more...
Hard core composters thrust their naked arms into a compost pile and grunt accordingly to determine how hot and hard the pile is working. The more squeamish composters can rely on compost thermometers. You couldn't pay me enough to thrust a naked appendage into my compost pile right now - maybe in a month. For a few days, my compost pile smelled bad. Reeeaaaally bad and I needed a quick way to fix things before the neighbors got out the pitch forks.
My pile turned anaerobic when I added a bunch of neglect and kitchen scraps saved over the winter to my compost pile. I have a pretty basic compost bin right now that makes turning my pile difficult, so I started trying out different techniques of aerating. To help guide my approach, I quickly rigged up a cheap DIY compost thermometer. The basic idea is that the hotter Read more...
I used to fear surface mount components... those damn teeny tiny sexy components that were too good for my weak soldering foo. Through hole components worked just fine for my low speed microcontroller circuits until one of my projects started to take off and we were looking at assembling a bunch of them. The temptation of soldering a bunch of boards all at once finally seduced me to start the journey towards SMD . This blog post will help you start cooking small batches of PCBs and making your own low cost solder paste stencil.
Continuing on from the Link-Depot sucks + USB debugging post, we know:
- The Link-Depot 4 Port LD-USH-4POW hub sucks. But how bad and why?
- The hub is reporting itself as USB 2.0 capable (Hi-Speed = 480 Mbps)
- In reality, the hub can only ever achieve USB 1.x speeds (Full-Speed = 12 Mbps)
- The hub reports a vendor ID of 1A40 which is reserved for Terminus Technology Inc.
- Suspect that the USB IC is actually High-Speed capable, but the overall circuit isn't
It's got a brand (Link-Depot) so surely it has to be better than an eBay sweatshop special. Oh wait... the Link-Depot brand only shows up on the packaging and no where on the actual hub.
Let's start pulling things apart!
Yuck! I feel dirty just looking at it. Right away you notice that the USB connectors have a shell pin that isn't soldered and the ones that are soldered aren't done very well. And what is that white crap all over the board? Some kind of flux residue? The random drops of solder are a nice touch, but my favorite is below!
TEARDOWN LINK AT BOTTOM.
I picked up two Link-Depot 4 Port USB 2.0 Hubs on sale ($5) from Memory Express and was quickly surprised at how bad they were.
The manufacturer (Link-Depot) is straight up lying about its High-Speed (480 Mbps) capability; the damn thing is super slow and will only do "Full-Speed" (12 Mbps). This kind of blatant false advertising really annoys me. There are lots of consumers out there that would never realize that they'd been tricked.
Model: LD-USH-4POW (SUCKS!)
Manufacturer: Link-Depot (SUCKS!)
Description: 4-Port USB 2.0 Hub with Individual Power Switches
What a steaming pile of dishonest marketing