The hourglass dramatically depicts the flow of time; gravity pulling grains of sand inevitably downward. So it is with the Bits of Time project by [Frank Andre]. The pixels drop, stopping only when the battery dies. Or, when your eggs are ready. (Pssst, it’s also on Hackaday.io.)
The project starts with a couple of [Frank’s] PixBlocks. A processor is added to one PixBlock to serve as the controller for both after they are connected via the serial bus. A tilt switch, with a debouncing circuit, is connected to an IO pin. This tells the processor the orientation of the box and therefore which way the pixels should flow.
Two switches set the duration of the timer in 15 second increments. A third starts the timer. When the box is rotated the pixels start flowing in the opposite direction. With code available on GitHub the system can be programmed for other effects such as changing colors, flickering, or even text display.
Sometimes it’s helpful to realize the truth that there is no spoon. At least, not with [Ronaldo]’s automatic self-stirring mug. At first it was just a small propeller in the bottom of the mug that turned on by pushing a button in the handle, but this wasn’t as feature-rich as [Ronaldo] hoped it could be, so he decided to see just how deep the automatic beverage-mixing rabbit hole goes.
The first thing to do was to get a microcontroller installed to handle the operation of the motor. The ATtiny13a was perfect for the job since it’s only using one output pin to control the motor, and can be configured to only draw 0.5 microamps in power-saving mode. This ensures a long life for the two AAA batteries that power the microcontroller and the motor.
As far as operation goes, the motor operates in different modes depending on how many times the button in the handle is pushed. It can be on continuously or it can operate at pre-determined intervals for a certain amount of time, making sure to keep the beverage thoroughly mixed for as long as the power lasts. Be sure to check out the video below for a detailed explanation of all of the operating modes. We could certainly see some other possible uses for more interesting beverages as well.
It’s awesome when you can tag-team with your dad to fix stuff around the house. [Ilias Giechaskiel], with help from his dad, did a complete refurbishing of a broken bathroom weighing scale, but not before trying to fix it first. The voltage regulator looked bust. Powering the rest of the circuit directly didn’t seem to work, and none of the passives looked suspect. Most of the chips had their markings scratched off and the COB obviously couldn’t be replaced anyway.
Instead of reverse engineering the LCD display, they decided to retain just the sensor and the switches, and replace everything else. The ATtiny85 seemed to have enough IO pins to do the job. But the strain-gauge based load cell, connected in a bridge configuration, did not have a signal span large enough to be measured using the 10 bit ADC on the ATtiny. Instead, they decided to use the HX711 (PDF) – a 24 bit ADC with selectable gain, specifically meant for use in weighing scales. Using a library written for the HX711 allowed interfacing it to the Arduino easy. The display was built using a 4 digit 7 segment display driven by the MAX7219. A slightly modified LEDcontrol library made it easy to hook up the display to the ATtiny. The circuit was assembled on a prototyping board so that it could be plugged in to another Arduino for programming.
Since they were running out of pins, they had to pull out a trick to use a single pin from the ATtiny to act as clock for the display driver and the ADC chip. Implementing the power-on and auto-off feature needed another interesting analog circuit block. Dad did the assembly of the circuit on a prototype board. In hindsight, the lack of IO pins on the ATtiny limited the features they could implement, so the duo are planning to put in an Arduino Nano to improve the hack. If you’re ever stuck with a broken scale, he’s made the schematic (PNG) and code available for use.
If you’re building a moving thing with a microcontroller, you’ll probably want to throw a servo controller in the mix. Driving a servo or two with a microcontroller takes away valuable cycles that just babysit the servo, making sure all the PWM signals are in sync. The thing is, most servo controllers are a massive overkill, and you don’t need that much to control a few servos over a UART. The proof of this is an attiny13 servo controller over on hackaday.io.
[arief] developed his tiny servo controller around one of the tiniest microcontrollers – the ATtiny13. This chip has just 1kB of Flash and 64 Bytes of RAM, but that’s enough to keep a few servos going and listen in to a UART for commands to drive the servo.
The construction of this servo controller board is simple enough – just a single sided board, microcontroller, and a few headers, caps, and resistors. Commands are sent to the ATtiny through a half duplex UART we covered before, with servos responding to simple serial commands.
If you’re building a robot army, this is the board to make. You’re going to need a high-powered controller to take over the world, but there’s no need to bog down that controller by babysitting a few servos.
The Arduino is a popular microcontroller platform for getting stuff done quickly: it’s widely available, there’s a wealth of online resources, and it’s a ready-to-use prototyping platform. On the opposite end of the spectrum, if you want to enjoy programming every bit of the microcontroller’s flash ROM, you can start with an arbitrarily tight resource constraint and see how far you can push it. [lucas][Radical Brad]’s demo that can output VGA and stereo audio on an eight-pin DIP microcontroller is a little bit more amazing than just blinking an LED.
[lucas][RB] is using an ATtiny85, the larger of the ATtiny series of microcontrollers. After connecting the required clock signal to the microcontroller to get the 25.175 Mhz signal required by VGA, he was left with only four pins to handle the four-colors and stereo audio. This is accomplished essentially by sending audio out at a time when the VGA monitor wouldn’t be expecting a signal (and [lucas][Rad Brad] does a great job explaining this process on his project page). He programmed the video core in assembly which helps to optimize the program, and only used passive components aside from the clock and the microcontroller.
Be sure to check out the video after the break to see how a processor with only 512 bytes of RAM can output an image that would require over 40 KB. It’s a true testament to how far you can push these processors if you’re determined. We’ve also seen these chips do over-the-air NTSC, bluetooth, and even Ethernet.
[Bob] built this simple device that can best be described as an electronic float valve. He was wasting a lot of water from overflowing water troughs and buckets around his farm. He would usually put the hose in the container, turn on the water valve and carry on with his work. By the time he remembered to come back, the area would be flooded. It’s obvious that there’s many different ways to solve a problem. For example, a simple mechanical float valve might have worked, but it’s not horse friendly and liable to get damaged soon.
The electronics is unabashedly minimal. An ATtiny85 controls a relay via a common variety NPN transistor. The relay in turn switches the solenoid valve. A push-button tells the microcontroller to start the water flowing, and when the water level gets high enough that it touches two hose clamps, the micro shuts it off again.
There’s some ghetto engineering going on here. The electronics is driven by a 9V battery, although the relay and the solenoid valve that [Bob] used are both rated for 12V. He’s not even using any sort of voltage regulation for the ATtiny, but instead dropping the voltage with a resistor divider. (We wonder about battery life in the long run.)
He built all of it on perf board and stuffed it inside a small enclosure, with two wires coming out for the level sensor and another two for the solenoid, and it seems to work. Check the video below where [Bob] walks through his build.
While some may point out the many short comings in this build, [Bob] found the one solution that works for him. Sometimes the right solution is what you’ve got on hand, and we’re glad he’s hacking away and sharing his work. And check out this wireless water level sensor that he built some time back.
A lot of young athletes who get concussions each year go undiagnosed, leading to brain injury. [Hunter Scott] is working on a device called Impact to help detect these events early. According to this article which discusses the issue of concussion recognition and evaluation, “Early identification on the sports sideline of suspected concussion is critical because, in most cases, athletes who are immediately removed from contact or collision sports after suffering a concussion or other traumatic brain injury will recover without incident fairly quickly. If an athlete is allowed to keep playing, however, their recovery is likely to take longer, and they are at increased risk of long-term problems”
The device is a dime sized disk, which has an ATTiny85 microcontroller, memory to hold data, an accelerometer and a LED which gets activated when the preset impact threshold is breached, all driven by a coin cell. This small size allows it to be easily embedded in sports equipment such as helmets. At the end of a game, if the LED is blinking, the player is then screened for a concussion. For additional analysis, data stored on the on-board memory can be downloaded. This can be done by a pogo-pin based docking station, which is what [Hunter Scott] is still working on.
He’s having a functional problem that needs fixing. The ATTiny85 cannot be programmed with the accelerometer populated. He first needs to populate the ATTiny85, program it, and then populate the accelerometer. He’s working in fixing that, but if you have any suggestions, chime in on the comments below. We’d like to add that [Hunter] is a prolific hacker. His project, the Ultra-wideband radio module was a Hackaday Prize semi-finalist last year.