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|The inside of the Geiger counter.|
The home-made Geiger counter featured in this post by forum user bob_day uses an A-Star 32U4 Micro, LND 7313 Geiger tube, and LCD to measure and display Geiger tube counts. The LCD displays the counts detected during the last minute, the average counts per minute, and the maximum counts in a minute. The project was originally designed for the Arduino Micro, but the program was able to run on the A-Star without any software modifications. The entire project is powered from one S7V8A adjustable step-up/step-down voltage regulator, and the conditioning part of the circuit, which shapes the output into narrow pulses, was designed by bob_day . Schematics and code for the project are included in the forum post.
|The case and display of the Geiger counter.|
We are now carrying four exciting new sensors from Interlink Electronics:
- 0.25″-diameter circle, short tail force-sensing resistor (FSR)
- 0.6″-diameter circle, short tail FSR
- 1.4″ × 0.4″ force-sensing linear potentiometer (FSLP) strip
- 4.0″ × 0.4″ customizable-length FSLP strip
The two force-sensing resistors (or FSRs, for short) are short-tail versions of the small, circular FSRs we already carry, which allows them to be integrated into applications with tighter space constraints. These sensors act just like variable resistors that depend on the applied pressure, so you can put them into a simple voltage divider circuit and measure the force on them with a single analog-to-digital (ADC) microcontroller input.
|0.6″-diameter short-tail force sensing resistor (FSR) next to a 0.6″-diameter FSR with a standard tail.|
The two force-sensing linear potentiometers (or FSLPs) take the force-measuring functionality of FSRs and add in the ability to detect the location of the force, all while being an entirely passive component that is incredibly easy to use.
|The two force-sensing linear potentiometers (FSLPs).|
These FSLPs are exciting because they enable fun new touch interfaces, not only for you to interact with your project but for your project to interact with the world. We decided to make a quick demo for the Las Vegas Mini Maker Faire 2014 to show just how easy it was to do something cool with this sensor. The video at the top of this blog post shows the demo in action.
In the demo, a 4.0″×0.4″ FSLP is used with an Arduino Uno R3 to meassure the position and pressure of the user’s finger. (For applications where space is tight, smaller modules like our Arduino-compatible A-Star Micro can be directly substituted for the Uno.) Using the strip requires four connections to a microcontroller and one additional resistor. Two of the required connections must be analog inputs. Four connections for one sensor might seem like a lot to deal with, but step-by-step procedures in section 5 of the sensor’s integration guide (513k pdf) make it easy to get the sensor working, and the Arduino code used in this demo is available on github to help get you started. A diagram of the connections made between the sensor, Arduino, and LED strip in this demo are shown below.
The connections shown in the diagram also work with the shorter 1.4″×0.4″ FSLP (referred to as “standard FSLP” in the integration guide), though the pin numbers that correspond to each of the sensors outputs (SL, D1, and D2) are different for the two sizes of FSLP. The pin numbers for each FSLP can be seen in Figure 9 of the FSLP Integration Guide. In the guide the 4.0″×0.4″ FSLP is referred to as a “10 cm FSLP”.
Once the Arduino reads the position and pressure data from the sensor, it sends signals to a WS2812B addressable LED strip that control the number of LEDs that turn on and their color. The further along the strip your finger moves the greater the number of LEDs that light up, and the more pressure you apply the more the color of all the LEDs changes from blue to red.
To make the demo easy to transport and able to be left on all day, a 9V wall adapter was used to power the Arduino and 5V step-down regulator. The power connections from the regulator’s 5V output to the power input of the LED strip were also simplified by using a DC barrel jack to terminal block adapter and a DC barrel plug to terminal block adapter. The structure of the demo was laser cut from 1/8″ clear acrylic, and aluminum standoffs were used as spacers.
If you guys do something cool with our force-sensing linear potentiometers or resistors, we’d love to hear about it!
The Las Vegas Mini Maker Faire 2014 was on April 5th, and as you might have heard, we had a booth there with demos of our products. For more about the faire and a video, see my previous blog post. This post details the Simple Motor Controller and Sharp analog distance sensor demo that we brought. The demo was popular at the faire with both kids and adults, and though it is simple, it is a great tool for showing those who are just getting interested in robotics what one of the first steps to building a robot might look like. Continued…
This PID line follower, originally featured in this Let’s Make Robots post by user Enigmerald, uses our 5" Robot Chassis along with 30:1 MP micro metal gearmotors, extended brackets, and our 42×19 mm wheels. Our QTR-8RC Reflectance Sensor Array is used to sense the line and our TB6612FNG carrier, along with an Arduino-compatible controller, is used to control the motors. A diagram of how everything is connected and the code for the robot are available in Enigmerald’s post. The post also has a link to a basic tutorial on PID tuning using the QTR array.
Last weekend Las Vegas had its second Mini Maker Faire. The event was hosted by the local hacker space Syn Shop and included booths with displays ranging from 3D printers, electric cars, and a full-size R2-D2 to art exhibits and handmade steampunk clothing. Pololu had a booth at the event with several demos of products like our Simple Motor Controllers, linear actuators, LED strips, and Zumo Robots. We will be following up this post later with others that detail some of the specific demos, but in the meantime, check out this video of the event!
Like several of the other engineers here at Pololu, I made a robot to compete in the LVBots Dead Reckoning Competition that took place recently. This post describes my robot, Tryangle, and the decisions that went into making it. For more information about what dead reckoning is and how it is judged, see the LVBots dead reckoning rules. Continued…
We are happy to introduce our D24V5Fx voltage regulator family, a next-generation version of our tiny D24V3Fx and D24V6Fx buck (step-down) regulators, which have been some of our most popular products. These new regulators are synchronous, which results in better efficiency, especially at light loads, and they have much lower dropout voltages (e.g. the 5 V version has just over 1 mV of dropout per mA of output current).
So far we have versions with 3.3 V, 5 V, 9 V, and 12 V outputs, and we will soon be releasing 1.8 V, 2.5 V, and 6 V versions; you can contact us for custom voltages, too. They operate with input voltages up to 36 V and have typical efficiencies of 80% to 93%. These regulators have integrated over-temperature and over-current shutoff, and they reduce their switching frequency from the typical 500 kHz to improve efficiency at light loads, making them well suited for low-power applications that are run from a battery.
At only 0.5″ × 0.4″ × 0.1″ (13 mm × 10 mm × 3 mm) these buck regulators are also smaller than standard through hole linear regulators with DIP packages. The picture below shows a D24V5Fx next to a 7805 voltage regulator in a TO-220 package.
This bipedal robot is controlled by an Android smartphone through a game pad, voice commands, or sensor gloves. It uses a custom Android API, which the creators plan to make open source, and two Maestro 24-channel servo controllers connected to the smart phone via USB. One Maestro is used to read 12 digital and 12 analog inputs, and the other is used to control 24 servos.
This robot was designed and made by Seeberger Robotics & Design, a startup company based in Switzerland. You can see more of their designs on their website.
Featured link: http://www.youtube.com/watch?v=XG_S4LsHqUA
We have released three new step-up regulators that can boost input voltages as low as 0.5 V and have typical efficiencies between 70 and 90%. Unlike most boost regulators, these offer a true shutdown option that turns off power to the load. They also automatically switch to a linear down-regulation mode when the input voltage exceeds the output, making them great for powering electronics projects from 1 – 3 NiMH, NiCd, or alkaline cells or from a single lithium-ion cell.