Arduino Projects And Programming

This started out as an investigation into how long I could run an Arduino on a small battery and still get it to do something useful. I had to choose the right Arduino board and figure out how to use the 'SLEEP_MODE_PWR_DOWN' mode.

With a little bit of gentle hacking of the board, editing a file in the Arduino IDE and flashing the fuses in the Arduino I managed to get the power consumption down to less than 5µA. At this level a 3v button cell should last for years but I still needed to make it do something.

"A christmas decoration" I said. I will make an LED icicle that drips every few seconds. Perfect I thought. Read on to find out how you can build one too. More...

The Arduino Pro-Mini is a tiny microcontroller with similar features to that of the UNO. It has a bootloader for uploading programs but unlike the UNO it doesn't have a USB interface so you need to use a USB to serial adapter to use it.

Why not use an In System Programmer (ISP) instead? You can use a cheap UNO as an ISP and you can then program the bootloader and fuses as well as the application program. Sounds like a win-win to me. More...

Do you have a 5v FTDI serial adapter and a 3.3v Arduino or Raspberry Pi? You know that you can't plug the adapter directly into the 3.3v microcontroller right but did you know that it's quite possible to build a simple voltage level converter to solve the problem?

I bought a 3.3v Arduino Pro Mini compatible board for a project but I made the mistake of ordering the wrong FTDI serial adapter. I got a 5v unit instead of a 3.3v one but I needed to use it quickly so I used 3 resistors to convert the levels so that I could use FTDI adapter with the 3.3v microcontroller. I thought that you might find this little converter board useful too More...

Let me show you how servo motors work and what you need to do to drive them. There's a handy library that you can use with Android which makes things very easy called 'Servo'. But what if you need to drive the servo some other way? If that's the case then you will need to know something about how they work.

I will show you how to connect one up and write a very simple Arduino sketch to experiment with. I explain exactly what goes on inside a servomotor and I finish up with a set of oscilloscope traces. If you want to know more about servo motors then read on. More...

How to build a simple but useful strobe based tachometer using an Arduino Uno, an LCD/Keypad shield and a few transistors, LED's and resistors. Short pulses are generated with a simple Arduino sketch and used to drive a bank of LED's. This produces short regular pulses of light which when synchronized with the speed of a fan or motor or other rotating object, makes the moving object appear to be standing still. When this happens the light pulse rate is equal to the RPM of the object. More...

Following on from the Arduino Distance Sensor project here is an updated version of the software sketch. Two new display modes have been added and the 'Select' key on the LCD keypad is used to swich between display modes. Full explanation of the software is provided. More...

Sensing the proximity of objects can be achieved effectively using ultrasonic echo techniques. Transmitting pulses of ultrasonic sound and measuring the time it takes the echo to return does present us with some interesting challenges however.

The sound can bounce off more than one object at different distances or the pulse is scattered. Sometimes the receiver doesn't even hear the echo. Luckily these problems can be overcome and a useful instrument built using an HC-SR04 ultrasonic transceiver and a little clever software running on an Arduino. More...

A reader emailed me a little while ago to ask for my help to program an Arduino board as a safety cut out. He was building a cartridge reloading machine that needed a safety cut out in situations where the motor jams. The solution using an Arduino Uno turned out to be remarkably simple. More...

Have you ever wondered how they make the parking sensors that you seem to find on all new cars? You know, the ones that start beeping when you are getting close to an object you should be avoiding. The beeping gets faster and faster as you get closer until the beeps all merge into one and... too late you've hit it! More...

Don't be afraid to use interrupts in your Arduino sketches. Interrupts enable you to do so much more with your Arduino that it's well worth taking the trouble to learn a few simple rules. Almost every project you work with, whether it's a user interface, a clock or you are controlling a robot, your sketches are likely to benefit from some use of the interrupt mechanism. More...