Planet Arduino

Ever on the lookout for creative applications for tech, [Andres Leon] built a solar powered battery system to keep his Christmas lights shining. It worked, but — pushing for innovation — it is now capable of so much more.

The shorthand of this system is two, 100 amp-hour, deep-cycle AGM batteries charged by four, 100 W solar panels mounted on an adjustable angle wood frame. Once back at the drawing board, however, [Leon] wanted to be able track real-time statistics of power collected, stored and discharged, and the ability to control it remotely. So, he introduced a Raspberry Pi running Raspbian Jessie Lite that publishes all the collected data to Home Assistant to be accessed and enable control of the system from the convenience of his smartphone. A pair of Arduino Deuemilanoves reporting to the Pi control a solid state relay powering a 12 V, 800 W DC-to-AC inverter and monitor a linear current sensor — although the latter still needs some tinkering. A in-depth video tour of the system follows after the break!

All the electronics are housed in a climate-controlled box which kicks on when the Pi’s CPU heats up — this is in a Florida backyard, folks — and powered off the battery system, with a handful of 40amp breakers between the components keep things safe. [Leon] has helpfully provided links to all the resources he used, as well as his code on GitHub.

We love homebrew solar power systems, but if only there was some way to take them on the road with us.

by openenergymonitor.org:

AC Voltage and current continually alternate, as the name suggests, if we draw a picture of the voltage and current waveform over time, it will look something like the image below (depending on what’s using power – the current waveform – blue in the diagram below – is what you get if you look at a typical laptop power supply. There’s an incandescent light bulb in there as well).

The image was made by sampling the mains voltage and current at high frequency, which is exactly what we do on the emontx or Arduino. We make between 50 and a 100 measurements every 20 milliseconds. (100 if sampling only current, and 50, if sampling voltage and current – we’re limited by the Arduino analog read command and calculation speed).

AC Power Theory – Arduino maths – [Link]

[Carl] recently upgraded his home with a solar panel system. This system compliments the electricity he gets from the grid by filling up a battery bank using free (as in beer) energy from the sun. The system came with a basic meter which really only shows the total amount of electricity the panels produce. [Carl] wanted to get more data out of his system. He managed to build his own monitor using an Arduino.

The trick of this build has to do with how the system works. The panel includes an LED light that blinks 1000 times for each kWh of electricity. [Carl] realized that if he could monitor the rate at which the LED is flashing, he could determine approximately how much energy is being generated at any given moment. We’ve seen similar projects in the past.

Like most people new to a technology, [Carl] built his project up by cobbling together other examples he found online. He started off by using a sketch that was originally designed to calculate the speed of a vehicle by measuring the time it took for the vehicle to pass between two points. [Carl] took this code and modified it to use a single photo resistor to detect the LED. He also built a sort of VU meter using several LEDs. The meter would increase and decrease proportionally to the reading on the electrical meter.

[Carl] continued improving on his system over time. He added an LCD panel so he could not only see the exact current measurement, but also the top measurement from the day. He put all of the electronics in a plastic tub and used a ribbon cable to move the LCD panel to a more convenient location. He also had his friend [Andy] clean up the Arduino code to make it easier for others to use as desired.

by embedded-lab.com:

This Arduino Nano controlled solar battery charger can charge a standard lead acid 12V battery and runs with 90% efficiency under 70ᵒC (158ᵒF). The circuit can take up to 24V input from the solar panels. The maximum power point tracking is implemented in the circuit by measuring the output voltage and current from the solar panel to get the maximum possible power from it.

Solar battery charge controller - [Link]

by embedded-lab.com

Infrared remote control for home appliances is a popular project among hobbyists and students. Smart Outlet is a similar project that provides an infrared controlled AC outlet to connect any electric appliance and has an integrated timer in it. The appliance can be turned on and off from several feet away using an IR remote. The device is Arduino-controlled and has a LCD display to provide a menu based interface to the user for its operation and settings.

Infra-red controlled smart AC outlet - [Link]

Kerry Wong built a DIY constant current/constant power electronic load. It can sink more than 200W of power:

A while back I built a simple constant current electronic load using an aluminum HDD cooler case as the heatsink. While it was sufficient for a few amps’ load under low voltages, it could not handle load much higher than a few dozen watts at least not for a prolonged period of time. So this time around, I decided to build a much beefier electronic load so it could be used in more demanding situations.
One of the features a lot of commercial electronic loads has in common is the ability to sink constant power. Constant power would come in handy when measuring battery capacities (Wh) or testing power supplies for instance. To accommodate this, I decided to use an Arduino (ATmega328p) microcontroller.

[via]

Building a constant current/constant power electronic load - [Link]

Introduction

Every month Australian electronics magazine Silicon Chip publishes a variety of projects, and in March 2004  they published the “DC-DC converter” project. Altronics picked it up and now offers a kit, the subject of our review. The main purpose of this converter kit is to allow replacement of expensive PP3 9V batteries with 2 AA cells, to enable a cheaper and longer lifespan over use. With a slight modification it can also act as a trickle-charger for 2 rechargeable AA cells (that can then supply power to the converter) via a plugpack. And there’s some educational value if you’re so inclined, as you can learn about voltage converters as well.

Assembly

As usual for Altronics the kit is in a typical retail package:

…which includes the detailed instructions (based on the original Silicon Chip article), a handy reference guide and of course the parts:

The PCB has a good silk screen and solder mask:

and all the required parts are included:

It was nice to see plenty of extra black and red wire for modifications or final installations, the battery snap, 2 x AA cell holder and a DC socket for use with the optional plug pack mentioned earlier. That hand-wound inductor was interesting, and I couldn’t help but measure it on the LC meter:

It was supposed to be a 47 uH inductor, so let’s hope that doesn’t cause too much trouble. Assembly was quite straight-forward – just start with the smallest components first and build up. If you’re not going to have the trickle-charge function, heed the notes in the manual and don’t install D2 or R4. The only fiddly bit was the “short as possible” (red) link across the board:

And after a few more minutes it was finished. The external connections will vary depending on your application – however for the review I’ve got the 9V snap on the input, which makes it easy to connect the 2 AA cell holder to power the converter. Nice to see the holes around the perimeter of the board, which make mounting it more permanently quite easy.

Operation

After a bench clean-up it was time to connect 2 AA rechargeable cells and see what we can get out of the converter. The cells measured 2.77V together before connection, and without a load on the converter the resulting output was 8.825 V:

We can live with that. Furthermore the quiescent current (a situation with the power connected and not having a load on the output) was 2.5 mA. Thus it would be a good idea to have a power switch in a real-world environment. Speaking of the real world (!) how much current can you get out of the converter? Generally PP3 battery applications are low current, as the battery itself isn’t good for that much – even an expensive “Energizer Ultimate Lithium” offers only 800 mAh (for $16). So using higher-capacity rechargeable AA cells and this kit will save money.  A table is included with the instructions that shows the possible uses:

According to the table my 2.77V supply should be good for ~80 mA. With some resistors in parallel we made a dummy load of 69 mA and measured 0.37A current draw from the AA cells. Thus the key to this kit – you find a cheaper or more plentiful power supply at a lower voltage to save you the expense of providing the higher voltage.

For example, if you had a pair of Sanyo Eneloop rechargeable AA cells (total 2.4 V at 2 Ah) they would give you around 5.4 hours of life (ignoring the fall-off of voltage towards the end of their charge life – however the eneloops are pretty good in that regard). Whereas a disposable PP3 mentioned earlier would offer around 2.1 hours (at $16) or a rechargeable unit (which offers 8.4 V at 175 mAh) would only last around 25 minutes. Note that you can change two resistors in the circuit to alter the output voltage, and the values have been listed in the instructions for outputs up to 15 V.

Finally, let’s consider the output waveforms from the circuit. With the aforementioned load, here’s the output on the DSO (click image to enlarge):

… and for interest’s sake, the switching output from the TL499 (click images to enlarge):

Conclusion

Apart from the described voltage-boosting functions this kit gives the interested builder experience with boost circuits and also the knowledge to create their own versions based on the original design, at a much lower cost than using other boost ICs . If you wanted a permanent certain voltage output, it would be better to breadboard the kit and experiment with the required resistors – then assemble the kit with the new values. And there is money and effort to be saved when subsituting with PP3 batteries. Finally, learning is a good thing!

So – a lot of fun and education for under $20. Purchase it from Altronics and their resellers, or read more about it in the September 2007 edition of Silicon Chip.

Full-sized images available on flickr. This kit was purchased without notifying the supplier.

And if you made it this far – check out my new book “Arduino Workshop” from No Starch Press.

In the meanwhile have fun and keep checking into tronixstuff.com. Why not follow things on twitter, Google+, subscribe  for email updates or RSS using the links on the right-hand column? And join our friendly Google Group – dedicated to the projects and related items on this website. Sign up – it’s free, helpful to each other –  and we can all learn something.

Introduction

Every month Australian electronics magazine Silicon Chip publishes a variety of projects, and in March 2004  they published the “DC-DC converter” project. Altronics picked it up and now offers a kit, the subject of our review. The main purpose of this converter kit is to allow replacement of expensive PP3 9V batteries with 2 AA cells, to enable a cheaper and longer lifespan over use. With a slight modification it can also act as a trickle-charger for 2 rechargeable AA cells (that can then supply power to the converter) via a plugpack. And there’s some educational value if you’re so inclined, as you can learn about voltage converters as well.

Assembly

As usual for Altronics the kit is in a typical retail package:

…which includes the detailed instructions (based on the original Silicon Chip article), a handy reference guide and of course the parts:

The PCB has a good silk screen and solder mask:

and all the required parts are included:

It was nice to see plenty of extra black and red wire for modifications or final installations, the battery snap, 2 x AA cell holder and a DC socket for use with the optional plug pack mentioned earlier. That hand-wound inductor was interesting, and I couldn’t help but measure it on the LC meter:

It was supposed to be a 47 uH inductor, so let’s hope that doesn’t cause too much trouble. Assembly was quite straight-forward – just start with the smallest components first and build up. If you’re not going to have the trickle-charge function, heed the notes in the manual and don’t install D2 or R4. The only fiddly bit was the “short as possible” (red) link across the board:

And after a few more minutes it was finished. The external connections will vary depending on your application – however for the review I’ve got the 9V snap on the input, which makes it easy to connect the 2 AA cell holder to power the converter. Nice to see the holes around the perimeter of the board, which make mounting it more permanently quite easy.

Operation

After a bench clean-up it was time to connect 2 AA rechargeable cells and see what we can get out of the converter. The cells measured 2.77V together before connection, and without a load on the converter the resulting output was 8.825 V:

We can live with that. Furthermore the quiescent current (a situation with the power connected and not having a load on the output) was 2.5 mA. Thus it would be a good idea to have a power switch in a real-world environment. Speaking of the real world (!) how much current can you get out of the converter? Generally PP3 battery applications are low current, as the battery itself isn’t good for that much – even an expensive “Energizer Ultimate Lithium” offers only 800 mAh (for $16). So using higher-capacity rechargeable AA cells and this kit will save money.  A table is included with the instructions that shows the possible uses:

According to the table my 2.77V supply should be good for ~80 mA. With some resistors in parallel we made a dummy load of 69 mA and measured 0.37A current draw from the AA cells. Thus the key to this kit – you find a cheaper or more plentiful power supply at a lower voltage to save you the expense of providing the higher voltage.

For example, if you had a pair of Sanyo Eneloop rechargeable AA cells (total 2.4 V at 2 Ah) they would give you around 5.4 hours of life (ignoring the fall-off of voltage towards the end of their charge life – however the eneloops are pretty good in that regard). Whereas a disposable PP3 mentioned earlier would offer around 2.1 hours (at $16) or a rechargeable unit (which offers 8.4 V at 175 mAh) would only last around 25 minutes. Note that you can change two resistors in the circuit to alter the output voltage, and the values have been listed in the instructions for outputs up to 15 V.

Finally, let’s consider the output waveforms from the circuit. With the aforementioned load, here’s the output on the DSO:

… and for interest’s sake, the switching output from the TL499:

Conclusion

Apart from the described voltage-boosting functions this kit gives the interested builder experience with boost circuits and also the knowledge to create their own versions based on the original design, at a much lower cost than using other boost ICs . If you wanted a permanent certain voltage output, it would be better to breadboard the kit and experiment with the required resistors – then assemble the kit with the new values. And there is money and effort to be saved when subsituting with PP3 batteries. Finally, learning is a good thing!

So – a lot of fun and education for under $20. Purchase it from Altronics and their resellers, or read more about it in the September 2007 edition of Silicon Chip.

Full-sized images available on flickr. This kit was purchased without notifying the supplier.

And if you made it this far – check out my new book “Arduino Workshop” from No Starch Press.

In the meanwhile have fun and keep checking into tronixstuff.com. Why not follow things on twitter, Google+, subscribe  for email updates or RSS using the links on the right-hand column? And join our friendly Google Group – dedicated to the projects and related items on this website. Sign up – it’s free, helpful to each other –  and we can all learn something.

The post Kit review – Altronics/Silicon Chip DC to DC Converter appeared first on tronixstuff.

Introduction

Every month Australian electronics magazine Silicon Chip publishes a variety of projects, and in December 2012 they published the USB Power Monitor by Nicholas Vinen. Jaycar picked it up and now offers a kit, the subject of our review. This small device plugs inline between a USB port and another device, and can display the current drawn, power and voltage at the USB port with a large LCD module. This is useful when you’re experimenting with USB-powered devices such as Arduino projects or curious how external USB devices can affect your notebook computer’s battery drain.

Assembly

The kit arrives in typical Jaycar fashion:

… everything necessary is included with the kit:

The instructions arrive as an updated reprint of the original magazine article, plus the usual notes from Jaycar about warranty and their component ID sheet which is useful for beginners. The PCB is quite small, and designed to be around the same size as the LCD module:

As you can see below, most of the work is already done due to the almost exclusive use of SMD components:

That’s a good thing if you’re in a hurry (or not the best with surface-mount work). Therefore the small amount of work requires is simply to solder in the USB sockets, the button and the LCD:

It took less than ten minutes to solder together. However – take careful, careful note of the LCD. There isn’t a pin 1 indicator on the module – so instead hold the LCD up to the light and determine which side of the screen has the decimal points – and line it up matching the silk-screening on the PCB. Once finished you can add the clear heatshrink to protect the meter, but remember to cut a small window at the back if you want access to the ICSP pins for the PIC microcontroller:

How it works

The USB current is passed through a 50 mΩ shunt resistor, with the voltage drop being measured by an INA282 current shunt monitor IC. The signal from there is amplified by an op amp and then fed to the ADC of a PIC18F45K80 microcontroller, which does the calculations and drives the LCD. For complete details purchase the kit or a copy of the December 2012 edition of Silicon Chip.

Operation

First you need to calibrate the unit – when first used the meter defaults to calibration mode. You simply insert it into a USB port. then measure the USB DC voltage brought out to two pads on the meter. By pressing the button you can match the measured voltage against the display as shown below – then you’re done.

Then you simply plug it in between your USB device and the socket. Press the button to change the measurement. The meter can measure the following ranges:

For an operational example. consider the next three images are from charging my phone – with the power, current and voltage being shown:

“P” for power…

current in mA

“b” for bus voltage

If you want to use the USB ports on the right-hand side of your computer, just press the button while inserting the meter – and it flips around:

Finally – here’s a quick video of the meter at work, whilst copying a file to an external USB hard drive:

Conclusion

I really like this – it’s simple and it works. Kudos to Nicholas for his project. You can purchase it from Jaycar and their resellers, or read more about it in the December 2012 edition of Silicon Chip. Full-sized images available on flickr. This kit was purchased without notifying the supplier.

In the meanwhile have fun and keep checking into tronixstuff.com. Why not follow things on twitter, Google+, subscribe  for email updates or RSS using the links on the right-hand column? And join our friendly Google Group – dedicated to the projects and related items on this website. Sign up – it’s free, helpful to each other –  and we can all learn something.

Introduction

Every month Australian electronics magazine Silicon Chip publishes a variety of projects, and in December 2012 they published the USB Power Monitor by Nicholas Vinen. Jaycar picked it up and now offers a kit, the subject of our review. This small device plugs inline between a USB port and another device, and can display the current drawn, power and voltage at the USB port with a large LCD module. This is useful when you’re experimenting with USB-powered devices such as Arduino projects or curious how external USB devices can affect your notebook computer’s battery drain.

Assembly

The kit arrives in typical Jaycar fashion:

… everything necessary is included with the kit:

The instructions arrive as an updated reprint of the original magazine article, plus the usual notes from Jaycar about warranty and their component ID sheet which is useful for beginners. The PCB is quite small, and designed to be around the same size as the LCD module:

As you can see below, most of the work is already done due to the almost exclusive use of SMD components:

That’s a good thing if you’re in a hurry (or not the best with surface-mount work). Therefore the small amount of work requires is simply to solder in the USB sockets, the button and the LCD:

It took less than ten minutes to solder together. However – take careful, careful note of the LCD. There isn’t a pin 1 indicator on the module – so instead hold the LCD up to the light and determine which side of the screen has the decimal points – and line it up matching the silk-screening on the PCB. Once finished you can add the clear heatshrink to protect the meter, but remember to cut a small window at the back if you want access to the ICSP pins for the PIC microcontroller:

How it works

The USB current is passed through a 50 mΩ shunt resistor, with the voltage drop being measured by an INA282 current shunt monitor IC. The signal from there is amplified by an op amp and then fed to the ADC of a PIC18F45K80 microcontroller, which does the calculations and drives the LCD. For complete details purchase the kit or a copy of the December 2012 edition of Silicon Chip.

Operation

First you need to calibrate the unit – when first used the meter defaults to calibration mode. You simply insert it into a USB port. then measure the USB DC voltage brought out to two pads on the meter. By pressing the button you can match the measured voltage against the display as shown below – then you’re done.

Then you simply plug it in between your USB device and the socket. Press the button to change the measurement. The meter can measure the following ranges:

For an operational example. consider the next three images are from charging my phone – with the power, current and voltage being shown:

“P” for power…

current in mA

“b” for bus voltage

If you want to use the USB ports on the right-hand side of your computer, just press the button while inserting the meter – and it flips around:

Finally – here’s a quick video of the meter at work, whilst copying a file to an external USB hard drive:

Conclusion

I really like this – it’s simple and it works. Kudos to Nicholas for his project. You can purchase it from Jaycar and their resellers, or read more about it in the December 2012 edition of Silicon Chip. Full-sized images available on flickr. This kit was purchased without notifying the supplier.

In the meanwhile have fun and keep checking into tronixstuff.com. Why not follow things on twitter, Google+, subscribe  for email updates or RSS using the links on the right-hand column? And join our friendly Google Group – dedicated to the projects and related items on this website. Sign up – it’s free, helpful to each other –  and we can all learn something.

The post Kit Review – SC/Jaycar USB Power Monitor appeared first on tronixstuff.