My brother has a solar panel on the roof of his house which is used to charge a 12v battery which runs the equipment in his attic, the routers etc. There is a proper solar regulator/battery charger which keeps the battery topped up. The problem is that when the sun isn’t shining (which happens a lot here!) the battery drains and eventually the voltage drops. He had bought a switch mode power supply that would take over from the solar regulator but he wasn’t sure how to wire it up to work as he wanted, which was to have the power supply on only when it was need so there would be no power wasted.
This is what i came up with for him.
As you may have seen from the RC car mods posts, i had to add a voltage boost module in to get it working. While it worked perfectly for that purpose i was skeptical of the claimed specifications – as you should be when buying cheap stuff from ebay.
Here is the details from the ebay auction:
Input voltage: DC 3-4.4V
Output voltage: DC 5.5V
Output current: 700mA (max)
Following on from the first post where the voltage was dropping when the motors were under load causing the arduino to reset i tried a couple of things to get around the problem, first i added another cap across the arduino supply and then i added another battery in series (to give 6V total) but still the voltage was dropping too much.
As i knew running an arduino from 4.5V was on the low side i went looking for a dc-dc boost to up the voltage to something more useful. What i found was a module used for charging USB devices from voltages down as far as 3V. These are rated at 700mA so more than enough for what we’re running off them. The actual output voltage is 5.5V which is in the acceptable range for the arduino.
With the Dublin Mini Maker Faire just around the corner i treated myself to a new toy to hack in its honour, yeah i know, any excuse. Everytime i look at my 1:18 scale delta integrale (a reminder of the one i used to own thats sorely missed!) i always think that it would make a great project to add working lights to it and have them controllable. Then i remember how much the model cost and i decide not to chop it up, not yet anyway. As i was browsing the argos site to look for anything interesting and cheap i came across this Porsche 911 GT3 RS which seemed like a nice buy.
Our TV is controllable over wifi from an android app and this has proved very useful as i’m rarely seen without my phone either in my hand or at least in my pocket. The TV remote (a Harmony One universal) has a habit of hiding down the side of the couch and generally going missing. The number one use for the TV is with the Sky HD satellite box and not being able to control it from the phone was definitely inconvenient (#firstworldproblems) and it’s something i wanted to remedy for quite a while and its something i started looking at a while back.
I picked up some IN-12B nixie tubes on ebay ages ago for no particular reason other than they’re pretty awesome! I had no way to run them as they require ~150 volts DC.
I came across the ArduiNIX shield, which has a built in boost circuit and dual output drivers allowing multiplexed control of 80 seperate elements which is enough for 8 tubes using the 0-9 elements or 7 tubes if using the decimal point.
The speedometer on my Opel Astra had taken to displaying random speeds a lot of the time and rather than replace the clock unit i decided it would easier, and more fun, to make some sort of display.
Being all electronic the clock unit only has one connector on the back with 36 pins which control all the gauges and warning lights.