Wednesday, June 17, 2009

Solar powered fireflies

I've been wanting to make something solar powered for some time & figured the firefly kit would be perfect to upgrade to solar power.

I just came across some cheap, second hand, solar powered light fixtures from allelectronics, which is a great place to pick up bits and bats for your electronic projects. Here's the actual solar lights I bought - solar-cell w/charging circuit. As the description says, they come with two solar panels, an LDR, a charging circuit (including - old - batteries) and some LEDs (one LED with this particular one and three with a different product).

As you can see from the pictures, all the components are easily acessible; these seemed perfect for hacking.

My first attempt was pretty simple, I just de-soldered the battery wires from my old JarOFireflies project, snipped the leads to the LED on the solar light kit and soldered the two kits together (the leads to the LED actually have a + and - designation printed on the board).

The LED wires are solid core and quite thick so there's no worry about them snapping under the strain and it made positioning the firefly board easier too. Speaking of which, I cut down the board to a more reasonable size for this project.

I didn't know if the batteries on the solar kit were duff so I left the hybrid out in the sunshine for a full day to charge then brought it indoors to see if it works:

And it does! What a pleasant surprise for something to work first time!

I think I'll cut a hole in the original jar's lid and place the kit in it more securely. Might be nice just to put it out in the garden to confuse the next door neighbours cats who seem to prefer our back yard to their own...

Saturday, June 6, 2009

555 noisemaker

When I started off on the electronics journey I bought the solar powered theramin kit (heliophone) from the makershed I thought it'd be a fun thing for the kids and would be a good starting point for learning to solder. The heliophone uses a solar panel to generate power and produces a clicking noise (the frequency of clicks varies with the intensity of ambient light).

The noisemaker I wanted to make sounds pretty similar but runs off a battery and uses a 555 timer to generate pulses which drive the speaker. Like with the heliophone kit, we alter the frequency of the 'clicks' with changes in ambient light intensity. In this case, it uses the standard "astable" set-up for the 555 and switches R1 for an LDR.

This is a pretty simple set-up and it makes a horrendously annoying noise; so it's perfect for the kids :) My inspiration for this came from this hack-a-day post on tiny-optical-theramins.

I'd already bought a few 555s and LDRs (again due to my eBay issues) so it seemed daft not to make something out of them, especially if the kids were likely to enjoy it.

Here's the final kit. I still want to house it in an interesting way, but I'll have to employ my lady's creative talent to produce something attractive. Maybe I'll paint an alien face on the tin with the LDR sticking through as it's mouth and get the kids to 'feed' it light.

Here's a little test run I did with Ffion, she got distracted pretty quickly by stuff going on in the next room...