Sudoku is a great way to pass some time, especially on a long flight. However, we don’t think the airlines will let [Sanahm] board with his sudoku-solving robot. The basic machine looks like a 2D plotter made with aluminum extrusion, with the addition of a Raspberry Pi and a camera. The machine can read a sudoku puzzle, solve it, and then fill in the puzzle with a pen. Unlike humans, it should never need to erase its work.
The software uses OpenCV to process the camera data, find the grid, and the cells provided by the puzzle. TensorFlow recognizes the numbers. From there, it is all just math to solve the puzzle. Once solved, the plotter part of the robot takes over and fills in the blanks. After all that, this seems like the easy part.
If you are working with OBD2 hardware or software, it’s easy enough to access test data, simply plug into a motor vehicle with an OBD2 socket. If, however, you wish to test OBD2 software under all possible fault conditions likely to be experienced by an engine, you are faced with a problem in that it becomes difficult to simulate all faults on a running engine without breaking it. This led [Fixkick] to create an OBD2 simulator using a secondhand Ford ECU supplied with fake sensor data from an Arduino to persuade it that a real engine was connected.
The write-up is quite a dense block of text to wade through, but if you are new to the world of ECU hacking it offers up some interesting nuggets of information. In it there is described how the crankshaft and camshaft sensors were simulated, as well as the mass airflow sensor, throttle position, and speedometer sensors. Some ECU inputs require a zero-crossing signal, something achieved with the use of small isolating transformers. The result is a boxed up unit containing ECU and Arduino, with potentiometers on its front panel to vary the respective sensor inputs.
We can race against the clock when assembling jigsaw puzzles online but what about competing against each other in the real world? [HomeMadeGarbage] came up with the simplest of solutions with his jigsaw puzzle timer that stops only when the puzzle’s completely assembled.
His simple solution was to attach copper foil tape to the back of the pieces, with overlap. He did this in a serpentine pattern to ensure that all pieces had a strip of the tape. The puzzle he used comes with a special container to assemble it in. At two corners of that container, he put two more pieces of copper foil, to which he soldered wires. Those two act as a switch. Only when the puzzle is completed will those two pieces be connected through the serpentine strip on the back of the puzzle.
Next, he needed a timer. The two wires from the puzzle container go to an Arduino UNO which uses an ILI9325 touch panel TFT display for both the start, stop, and reset buttons, and to show the time elapsed. Press the touch screen when it says START and begin assembling the puzzle. When the last piece is inserted, the serpentine strip of copper tape completes the circuit and only then does the Arduino program stop the timer. As you can see from the video below, the result makes doing the puzzle lots of fun.
If you want to wirelessly communicate between devices, WiFi and Bluetooth are obvious choices. But there’s also the ISM (industrial, scientific, and medical) band that you use. There are inexpensive modules like the SX1278 that can handle this for you using LoRa modulation, but they haven’t been handy to use with an Arduino. [Jan] noticed the same thing and set out to build a shield that allowed an Arduino to communicate using LoRa. You can find the design data on GitHub. [Jan] calls it the LoRenz shield.
According to [Jan], the boards cost about $20 to $30 each to make, and most of that cost was in having PC boards shipped. LoRa lets you trade data rate for bandwidth, but typical data rates are fairly modest. As for range, that depends on a lot of factors, too, but we’ve seen ranges quoted in terms of miles.
Depending on where you live, there may be legal restrictions on how you use a radio like the SX1278. You should understand your local laws before you buy into using the ISM bands. We aren’t sure it would be wise, but the board can coexist with three other similar shields. So you could get 4 radios going on one Arduino if you had too and could manage the power, RF, and other issues involved. The breakout board the module uses has an antenna connector, so depending on your local laws, you could get a good bit of range out of one of these.
[Jan] promises a post on the library that makes it all work shortly, but you can find the code on GitHub now. If you look at the code in the examples directory, it seems pretty easy. You’d have to sling some software, but the SX1278 can support other modes in addition to LoRA including FSK and other data modulation techniques.
We’ve seen other LoRa shields, but not many. If you are interested in other wireless technologies, we’ve talked about them quite a bit. If you want a basic introduction to LoRa, [Andreas Spiess’] video below is a good place to start.
A good robot is always welcome around here at Hackaday, and Hackaday.io user [igorfonseca83]’browser-controlled ‘bot s is no exception. Felines beware.
[igorfonseca83] — building on another project he’s involved in — used simple materials for the robot itself, but you could use just about anything. His goal for this build was to maximize accessibility in terms of components and construction using common tools.
An Arduino Uno gets two D/C motors a-driving using an H-bridge circuit — granting independent control the wheels — an ESP8266 enabling WiFi access, with power provided by a simple 5V USB power bank. [igorfonseca83] is using an Android smartphone to transmit audio and video data; though this was mostly for convenience on his part, a Raspberry Pi and camera module combo as another great option!
Feel like taking a long walk, but can’t be bothered with carrying your drinks? Have no fear, this “Follow Me” Cooler Bot is here!
Really just a mobile platform with a cooler on top, the robot connects to smartphone via Bluetooth, following it using GPS. Making the platform involves a little woodworking skill, and an aluminium hub with a 3D-printed hub adapter connects the motors to a pair 6″ rubber wheels with a swivel caster mounted at the rear. A pocket in the platform’s base houses the electronics.
The Arduino Uno — via an L298n motor driver — controls two 12V DC, brushed and geared motors mounted with 3D printed brackets, while a Parallax PAM-7Q GPS Module in conjunction with an HMC 5883L compass help the robot keep its bearing. A duo of batteries power the motors and the electronics separately to prevent any malfunctions.
[Ben Parnas], and co-conspirator in engineering inanity [Greg Daneault], brought to the recent Boston Stupid Hackathon in Cambridge, MA, their IoT-enabled Fidget Spinner…. spinner. A Spidget Finner. Yep, that’s correct: spin the smartphone, and the spinner follows suit. Stupid? Maybe, but for good reason.
Part satire on cloud tech, part learning experience, a curt eight hours of tinkering brought this grotesque, ESP32-based device to life. The ESP can the Arduino boot-loader, but you’ll want to use the ESP-IDF sdk, enabling broader use of the chip.
Creating an app that pulls data from the phone’s gyroscope, the duo set up the spinner-bot to access the WiFi and request packets of rotational data from the smartphone via a cloud-based server — the ‘spincloud.’ Both devices were enabled as clients to circumvent existing IoT services.