Microcontrollers

2381 Articles

DIY Digital Bench Power Supply

June 6, 2011 by 30 Comments

[Guido Socher] built himself a great little bench power supply that’s able to put out 30 Volts at 2 Amps.

Instead of taking the easy way out by putting a few taps on an ATX power supply, this project was built around a generic 24 Volt laptop power brick. An ATmega8 generates a PWM signal that is sent though a low-pass filter, allowing everything to be very precisely controlled. This DC signal is then sent through a BD245 power transistor to bring everything up to the desired output. [Guido Socher] included a USB port for computer control of everything, and the final project is something we’d be happy to have on our bench.

We’ve seen a few computer power supplies converted into a bench power source, but we’re impressed with [Guido Socher]’s build log. It’s not often we see a hack that goes over the theory of operation, and the end product is very nice (and functional) too.

Washing Machine Mechanical Timer Replaced With Microcontroller

June 5, 2011 by 12 Comments

After the electromechanical timer on [Paul Canello’s] washing machine broke for the third time he decided he needed to stop repairing it and find a more permanent fix. He decided to build his own microcontroller-based system for washing his clothes (translated). Caution: The image links on [Paul’s] page seem to be broken and will unleash a never-ending storm of empty pop-up windows if you click on them. We’ve embedded all of the images after the break to save you some hassle.

The controller on a washing machine is nothing more than a mechanical alarm clock. It starts the cycle, then moves through various modes based on the passage of time. [Paul] started his hack by observing how long the delay between cycles was meant to be, and recording which parts of the machine were switched on and off at each stage.

It turns out that when the mechanical knob is turned, it reroutes how water flows through the detergent chamber. Since that knob won’t be in the new system [Paul] came up with a way for the microcontroller to handle this by using a servo motor. The rest of the control involves relays to control the motor, and solenoid valves for the water. There are also pressure switches that give feedback for the level of the water in the machine. A PIC 16F872 serves as the new controller, with the help of a 7 segment display, a buzzer, and a pair of buttons as the user interface.

This is an older project, but after reading about the Arduino controlled dishwasher [Ramiro] sent us a link. Thanks! Continue reading “Washing Machine Mechanical Timer Replaced With Microcontroller” →

Precision Frequency Measurement Library For 8-bit Microcontrollers

June 3, 2011 by 7 Comments

[Paul] has been working on porting over Arduino libraries for use with the Teensy microcontroller platform. This tends to be pretty simple since they both use the same Atmel chip architecture. But once in a while he finds the Arduino libraries are not what they’re cracked up to be. When looking to port over a frequency measurement library he ended up writing his own that works better and is much more portable.

He had two big beefs with the Arduino Frequency Counter Library. The first is that it required the compensation factor the be calibrated using an accurate frequency counter. That’s a chick-and-egg problem since many people who build a frequency counter with an Arduino are doing so because they don’t already have a standalone tool. The second problem is that the Arduino library was hardcoded for ATmega168 or ATmega328 chips.

This new library fixes both issues with just one trade-off. Your hardware setup must be using a crystal oscillator. You can see above in the image above that the frequency measurement is quite accurate with this method. The package also uses a thin abstraction layer which will make it easy to port to any 8-bit microcontroller which is programmed in C.

VGA Out On A Maple Board

June 2, 2011 by 8 Comments

The team at Leaf Labs just released a new library to demonstrate the VGA capabilities of their Maple dev board. Although it’s only a 16 by 18 pixel image, it shows a lot of development over past video implementations on the Maple.

The Maple is a great little Ardunio-compatible board with a strangely familiar IDE. We’ve covered the Maple before. Instead of the somewhat limited AVR, the Maple uses an ARM running at 72MHz, making applications requiring some horsepower or strict timing a lot easier.

We’ve seen a few projects use the increased power, like a guitar effects shield. It’s possible the Maple could be made into a game console that would blow the Uzebox out of the water, but we’re wondering what hackaday readers would use this dev board for.

Watch the video after the jump to see how far the Maple’s VGA capability has come after only a few months, or check out Leaf Lab’s Maple libraries.

Continue reading “VGA Out On A Maple Board” →

ChipKIT Uno32: First Impressions And Benchmarks

May 27, 2011 by 49 Comments

Following Maker Faire, we’ve had a few days to poke around with Digilent’s 32-bit Arduino-compatible chipKIT boards and compiler. We have some initial performance figures to report, along with impressions of the hardware and software.

Continue reading “ChipKIT Uno32: First Impressions And Benchmarks” →

Color Object Tracking With An 8-bit Microcontroller

May 25, 2011 by 20 Comments

[Craig] sent in a link to this project which manages to implement color tracking on an 8-bit microcontroller at 60 frames per second. That’s some pretty incredible performance, but we’re also not talking about using a hobby-grade microcontroller. The C8051F360 is an ARM microcontroller with 100 MIPS throughput and with a system clock that can operate at up to 100 MHz. You also must consider that the chip will be able to do nothing else while in the tracking mode. Even with those gotchase, it’s still pretty incredible.

The setup uses an Omnivision OV7720 camera module. It has its own 24 MHz clock, which is used as the clock signal on the microcontroller’s PLL to generate a 96 MHz system clock. The code, which is written in a combination of C and assembly language, pushes captured tracking data to a PC via a serial port connection. After the break you can watch a bare-bones demo video that illustrates what the camera sees and what data shows up on the PC.

If you had the system in hand, what would you use it for? Perhaps it’s a perfect addition to that paintball sentry gun at which you’ve been hacking away?

Continue reading “Color Object Tracking With An 8-bit Microcontroller” →

Great Junk-yard Find Leads To A Reclaimed Control Panel Project

May 23, 2011 by 5 Comments

Having the “can you believe somebody threw this away?” mentality has gotten us into some trouble through the years, but look what [Joshua] found at the scrap yard! It’s a door from a power conversion station and it contains fourteen indicator lights and a lot of other doodads. But since this is just the door, he needed a way to monitor the controls and drive the indicators. At the heart of the hack he used to get this up and running is a PIC 18F2550. It has no trouble driving the indicators thanks to a pair of ULN2803 darlington arrays which switch the higher 24 volt levels.

His writeup doesn’t mention the method used, but the panel also has a couple of meters at the top. In the video after the break you can clearly see that he’s got them both working. We’d bet there’s a plan for each of the buttons as well, since this will be prominently featured in their alien-invasion themed Halloween display this year.

Continue reading “Great Junk-yard Find Leads To A Reclaimed Control Panel Project” →