chromei386

Thanks, I do think constant source of current to the battery would be very useful to charge the battery faster

Feasibility study? They already make these

Looks cool

You will need to be specific in what you are looking for What is the power (watts) requirements of the home appliances? Are they 110/240V AC appliances? Will you be supplementing from the grid or is it a standalone system?

I realise I was being a lazy bum. Here's something more specific I drew up. I think it will work!

Maxim gave me the shaft, but Texas Instruments sent as International Priority Mail.

It may be easier to do it via a platform such as Arduino - http://www.arduino.cc/ - they have tutorials and sample code on hooking up sensors, adjusting sensitivity, sound makers, etc. Designing projects is costly, and can quickly consume time and resources. Remember all this requires testing to make sure it works on the day. Anyone who knows exactly how to do this properly won't be cheap unless you happen to have an engineer as a partner. Even then... ! Say you have everything technical sorted, what would the final product look like? You'd need an enclosure, with large buttons for selection, LED indicators for which sound is selected, pictures of each animal above? Where does the pressure sensor go? And all of this being "child proof" - which would be a huge consideration in design. Sensitive, calibrated electronics + Children = On the floor in pieces and wondering why you even bother getting up the morning What is your budget in terms of time and money? Even small projects have a way of taking up much more time and money than you would want or expect.

Some key issues I see arising are: How many LEDs and what type will it take to provide adequate lighting (if these are for replacements for normal street lights). What is the lighting requirement, is there any benchmark? What is the power drain? How will you store the energy - SLA batteries? NiMH? NiCd? How long will they be able to provide lighting at load requirements? What are your weight requirements? (Large SLAs are heavy, and could pose a danger if up high). What is your backup plan, if there is no sun for days. Do you feed from the grid?

I'm not sure what you're referring to?

Don't attempt to solder the battery if it is not designed to be soldered as it may damage the battery / leak / explode (?) Maybe buying a separate small battery holder instead would work?

I think you'd be pushing your luck asking for them to pay for an air conditioner. For buying one, check if someone is selling one via online classifieds - maybe one second hand- but quite new, i.e. they bought it 2 months ago and now are moving overseas, etc. And make sure you get good warranty! You can sometimes negotiate extended warranties (on site) down to 20% of the asking price as these have a huge profit margin.

What do you want the DC power supply to power? I'm not sure exactly of that model, but if you're doing using it to power sensitive electronics with ICs, etc, it would be better off with a stable regulated power supply. Maybe check if it's regulated..

I don't use Macs, but have you tried basic troubleshooting, such as trying different USB ports, checking cable connections, checking hardware devices. Maybe it just needs an updated driver from the Canon website. Or even just Apple system updates

Hi KevinIV, That is not how I intended it to operate. I don't really know what I'm talking about, but this is my idea behind the design: The 16V regulator comes from a computer PSU. The first voltage divider (20k/100k) acts as the Reference voltage - which is about 13.56V in real life - to the Voltage Comparator IC. The second voltage divider (15k/100k) acts as the Battery voltage reference, which is fed into the Voltage Comparator IC as well. When the Battery voltage goes higher than the Reference voltage, the Output from the Voltage comparator IC switches on an LED and switches off power to the battery via that relay - apart from a very weak trickle charge (via the 1k resistor which bridges across the relay). The 3.3 Ohm resistor acts a voltage shunt and the voltage across it is the supply voltage minus the battery voltage. As the battery voltage increases, the voltage across the Battery voltage reference increases as well.

Oh I think I probably confused people with all the different diagrams. The battery is getting > 14V across the terminals when charging, as measured with multimeter as per the design, but the "supply voltage" comparison voltage for the voltage comparator is not getting above 12.8V. And in fact when I disconnect the battery, and measure open circuit voltage straight away it is still only around that 12.8V mark.