Arduino Projects

A list of serious Arduino based projects I have made that I think are worth making by others if you so wish. I have not included any experimental or prototype projects; if you want to see everything I’ve dabbled with and talked about please see the home page.


NIMH AA and AAA battery tester

A automatic battery tester which discharges up to 3 AA or AAA cells and displays the resulting true mAh rating on an LCD. Can be adapted to test lithium cells with code modification. Originally based on a project by Brian Hobbs but has some modifications by me to improve ease of use and accuracy. Uses an Arduino nano (Mega 328) as the controller. Proved to be quite accurate as long as the 5V supply voltage is kept to as close to 5V as possible e.g use a good quality regulator.


LCD alarm clock with multiple alarms and 1 sec per month accuracy with DS1307 RTC.

A decent alarm clock which displays time, date and temperature on a 16×2 LCD. Features multiple alarms with several melodies and up to 1 second per month accuracy with a standard DS1307 by using code to compensate for time drift. Again uses an Arduino nano but a Uno can be used with the case used in the project. Due to some of the changes I made to the code this should be used in 24 hour time display mode but a larger LCD could be used instead.


2.4Ghz (wifi) band scanner

A simple wifi band scanner which was built to detect interference from other non wifi devices that use the 2.4Ghz band. Displays output on a serial port and uses the poor man’s wifi scanner base source code. Useful for diagnosing wifi signal problems. This came in handy for finding the cause of wireless signal dropouts when signal strength was OK and routers replaced to no avail. The problem was external interference which only this scanner can detect rather than your usual smartphone app.


Scrolling message display

Not really a serious project as such but this was completed and cased and would come in handy for a educational project or simply to display a custom message during special events. Two further revisions were made, the first added a clock function that would show the date and time before the message and the third did the same replacing the message if a sensor input threshold was met. This was used with a gas sensor for experimentation during the planning of a future project. It serves as a clock / scrolling message display now.

 


Gas & smoke detector / air quality meter

This is another quick gadget I built as I have been experimenting with gas sensors for a planned project in the near future. This is an arduino based gas monitor which uses a MQ-2 sensor to detect hydrogen, methane, natural gas, alcahol and smoke. I had finished my experiments with the MQ-2 sensor and decided it was unsuitable for the planned project which was to detect unsafe levels of gas in battery charging rooms. I had a spare case and a Mega 328 microcontroller which had some faulty pins so I used it to build this simple device as I didn’t need all pins. All it does is basically display the analog value on a 7 segment display which with MQ-2 connected displays around 8-15 in clean air and a much higher value depending on the gas level. It also detects farts 🙂 This could easily be repurposed for something else though but it demonstrates driving a multi digit 7 segment display showing an analog value.


6 input digital voltmeter with up to 50V range

6 input Digital Voltmeter 0-50V range.This was designed as an add-on for a battery tester we use at work but can be used for any situation where the need to measure up to 6 voltages at once. It is powered from a 24V DC supply and uses an Arduino nano as the microcontroller. The incoming 24V supply is dropped to 9V via a regulator so it can be fed into the nano board. It uses the default analog reference as accuracy wasn’t a must have in our application (its only accurate to one decimal place) but for other uses an external precision reference IC should be used. However the code has the ability to calibrate the input channels to a reasonable level.


H2S Gas detector & monitor with automatic charger disconnection

This is a project I made for work which monitors Hydrogen Sulphide levels in the area where we charge our lead acid batteries. Often batteries are left on charge unattended so I designed a system that would automatically turn off the power to the chargers if gas from a faulty battery was detected. With it simply turning on a relay to disconnect the power it could also turn on an extractor fan. The monitor will also sound an alarm and continue to do so even if gas levels return to normal. An LCD shows how long ago the alarm was tripped. The system can then be reset after the faulty battery identified and the power is restored.