microcontroller

368 Articles

Laser Galvo Control Via Microcontroller’s DAC

February 15, 2018 by 33 Comments

Mirror galvanometers (‘galvos’ for short) are the worky bits in a laser projector; they are capable of twisting a mirror extremely quickly and accurately. With two of them, a laser beam may be steered in X and Y to form patterns. [bdring] had purchased some laser galvos and decided to roll his own control system with the goal of driving the galvos with the DAC (digital to analog) output of a microcontroller. After that, all that was needed to make it draw some shapes was a laser and a 3D printed fixture to hold everything in the right alignment.

The galvos came with drivers to take care of the low-level interfacing, and [bdring]’s job was to make an interface to translate the 0 V – 5 V output range of his microcontroller’s DAC into the 10 V differential range the driver expects. He succeeded, and a brief video of some test patterns is embedded below.

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ATtiny Chip Abused In RFID Application

January 5, 2018 by 21 Comments

One of Atmel’s smallest microcontrollers, the ATtiny, is among the most inexpensive and reliable chips around for small applications. It’s also one of the most popular. If you don’t need more than a few inputs or outputs, there’s nothing better. As a show of its ability to thrive under adverse conditions, [Trammell Hudson] was able to shoehorn an ATtiny into an RFID circuit in a way that tests the limits of the chip design.

The RFID circuit only uses two of the ATtiny’s pins and neither of which is the ground or power pin. The ATtiny is equipped with protective diodes on its input pins, and if you apply an AC waveform to the input pins, the chip is able to use the leakage current to power itself. Once that little hurdle is crossed, the ATtiny can do the rest of its job handling the RFID circuitry.

This project takes a deep dive into the internals of the ATtiny. If you’ve ever wondered what was going on inside of everyone’s favorite tiny microcontroller, or if you’re looking for an RFID circuit that keeps parts counts to an absolute minimum, this is the project for you.  The ATtiny is more than just a rugged, well-designed chip, though. It’s capable of a lot more than such a small chip should be able to.

Thanks to [adnidor] for the tip!

Balance Like A Mountain Goat On This Simple Stewart Platform

December 27, 2017 by 4 Comments

No goats were harmed in the making of this 3-DOF Stewart platform for [Bruce Land]’s microcontrollers course at Cornell.

If the name “Stewart platform” doesn’t ring a bell, the video below will help you out. [Team Microgoats] built a small version of the mechanical system commonly seen in flight simulators, opting for 3 DOF  to simplify the design. Their PIC32-controlled steppers can wobble and weave the table in response to inputs from an MPU-6050 six-axis accelerometer embedded in the base of a 3D-printed goat. Said goat appears to serve no other role in the build, but goats are cool, so why not? And if you’ve ever seen a mountain goat frolicking across a sheer vertical rock face like it was walking across a parking lot, you’ll understand the connection to the balance and control offered by a Stewart platform.

[Bruce Land]’s course is always a bonanza of neat projects that pop up in our tipline this time of year, like a POV box fan, a coin cell Rickrolling throwie, and a dynamometer for small electric motors.

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Small Jet Engine Model From Students Who Think Big

December 18, 2017 by 21 Comments

We love to highlight great engineering student projects at Hackaday. We also love environment-sensing microcontrollers, 3D printing, and jet engines. The X-Plorer 1 by JetX Engineering checks all the boxes.

This engineering student exercise took its members through the development process of a jet engine. Starting from a set of requirements to meet, they designed their engine and analyzed it in software before embarking on physical model assembly. An engine monitoring system was developed in parallel and integrated into the model. These embedded sensors gave performance feedback, and armed with data the team iterated though ideas to improve their design. It’s a shame the X-Plorer 1 model had to stop short of actual combustion. The realities of 3D printed plastic meant airflow for the model came from external compressed air and not from burning fuel.

Also worth noting are the people behind this project. JetX Engineering describe themselves as an University of Glasgow student club for jet engine enthusiasts, but they act less like a casual gathering of friends and more like an aerospace engineering firm. The ability of this group to organize and execute on this project, including finding sponsors to fund it, are skills difficult to teach in a classroom and even more difficult to test with an exam.

After X-Plorer 1, the group has launched two new project teams X-Plorer 2 and Kronos. They are also working to expand to other universities with the ambition of launching competitions between student teams. That would be exciting and we wish them success.

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Fully-functional Oscilloscope On A PIC

December 10, 2017 by 15 Comments

When troubleshooting circuits it’s handy to have an oscilloscope around, but often we aren’t in a lab setting with all of our fancy, expensive tools at our disposal. Luckily the price of some basic oscilloscopes has dropped considerably in the past several years, but if you want to roll out your own solution to the “portable oscilloscope” problem the electrical engineering students at Cornell produced an oscilloscope that only needs a few knobs, a PIC, and a small TV.

[Junpeng] and [Kevin] are taking their design class, and built this prototype to be inexpensive and portable while still maintaining a high sample rate and preserving all of the core functions of a traditional oscilloscope. The scope can function anywhere under 100 kHz, and outputs NTSC at 30 frames per second. The user can control the ground level, the voltage and time scales, and a trigger. The oscilloscope has one channel, but this could be expanded easily enough if it isn’t sufficient for a real field application.

All in all, this is a great demonstration of what you can accomplish with a microcontroller and (almost) an engineering degree. To that end, the students go into an incredible amount of detail about how the oscilloscope works since this is a design class. About twice a year we see a lot of these projects popping up, and it’s always interesting to see the new challenges facing students in these classes.

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Sensing Soil Moisture: You’re Doing It Wrong!

November 16, 2017 by 105 Comments

If you compulsively search online for inexpensive microcontroller add-ons, you will see soil moisture measurement kits. [aka] built a greenhouse with a host of hacked hardware including lights and automatic watering. What caught our attention among all these was Step 5 in their instructions where [aka] explains why the cheap soil sensing probes aren’t worth their weight in potting soil. Even worse, they may leave vacationers with a mistaken sense of security over their unattended plants.

The sensing stakes, which come with a small amplifier, work splendidly out of the box, but if you recall, passing current through electrodes via moisture is the recipe for electrolysis and that has a pretty profound effect on metal. [Aka] shows us the effects of electrolysis on these probes and mentions that damaged probes will cease to give useful information which could lead to overworked pumps and flooded helpless plants.

There is an easy solution. Graphite probes are inexpensive to make yourself. Simply harvest them from pencils or buy woodless pencils from the art store. Add some wires and hold them with shrink tube, and you have probes which won’t fail you or your plants.

Here’s some garden automation if this only whet your whistle, and here’s a robotic friend who takes care of the weeds for you.

Weather Station Needs Almost No Batteries

November 13, 2017 by 38 Comments

While the ESP8266 has made its way into virtually every situation where a low-cost WiFi solution is needed, it’s not known as being a low-power solution due to the amount of energy it takes to run WiFi. [Alex] took this design constraint as more of a challenge though, and with the help of an ATtiny microcontroller was able to develop a weather station using an ESP8266 that only needs new batteries every 2-4 years.

While the ESP8266 module consumes a bit of power, the ATtiny excels in low-power mode. To take advantage of this, [Alex] designed the weather station using the ATtiny to gather data every two minutes, store the data in a buffer, and upload all of it in bursts every hour using the ESP8266. This means that the power-hungry WiFi chip can stay off most of the time, drastically limiting the power demands of the station. [Alex] mostly details the setup of the ATtiny and the ESP8266 on his project page, so this could be applied anywhere that low power and network connectivity are required.

As for the weather reporting capabilities, the station is equipped to measure temperature, light, and humidity. Presumably more could be added but this might increase the power demands for the weather station as a whole. Still, changing batteries once a year instead of once every two years might be a worthwhile trade-off for anyone else attempting such an ambitious project. Other additions to the weather station that we’ve seen before might include a low-power display, too.