Arduino At Home DIY Electronics

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...

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...

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...

One of the most versatile of the Arduino family is the Pro-Mini. Its tiny footprint and low power make it ideal for many battery powered devices. However it lacks a USB port and an ISP programming connector which makes it a little more difficult to program.

You can either attach an FTDI USB to serial converter and program it using the bootloader like other Arduinos or you can program it using the ISP programmer built onto this break out board. Don't worry, the ISP programmer is no more difficult to use than the bootloader and it also allows you to reprogram the bootloader and the configuration fuses. This is most important when configuring the board to run at very low current consumption and you can't do that with the bootloader. 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...

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...

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...

Driving an LED from a 5v microcontroller is no problem. Flashing a red, blue, green or yellow LED should be possible even with a microconroller running at 3v but what if you want to drive a white LED that doesn't strart to illuminate until it's voltage gets to about 3.1v?

Worse still what if you are designing a battery operated device and you wanted to squeeze every last second of juice from the battery by allowing the voltage to drop to the minimum the microcontroller will work at? This would be 1.8v in the case of an Arduino chip which is way short of a glowing white LED. The solution is to add a voltage multiplier to the controller output driving the LED. 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...

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...