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Condensation on the circuit

I've worked much on the circuit for the "inflatable condoms" project. I've ran in so many problems. The biggest one is the electrical management. I had to fine tune the length and dynamics of the "heat release" process, that is, the part of the program where, when the sun sets, the blowers start to be activated.

After many tests and computations, I found out that I should be extremely careful not to run that process for too long nor to activate too many blowers. I've come up with the conclusion that, during a 1h15 heat release process, an average of 0.7 blowers should be activated at any one time. This approximation is based on the output of my solar panels (2 x 3.6V = 7.2V, 50mA) with an average illumination of 8 hours per day.

My experiments have shown that during the usual days here (where there's a lot of sun, especially around noon) the batteries (5 x 1.2V = 6V) get completely recharged during the day. However, the last two days of the week were a bit cloudy and the batteries could not recharge.

Luckily, even when not in sleep mode, the ATmega168 consumes very few. I've divided the internal clock by 8, which means it runs at 1MHz, which is fast enough for this application. At that frequency, it consumes between 0.25 mA and 1.0 mA (!) In sleep mode (which is activated during the night), it consumes almost nothing (10 nA !)

Anyway, in order to avoid the circuit to completely empty the batteries, I've added a small voltage monitoring circuit. It uses the 1.1V internal reference of the ATmega168, a simple voltage divider circuit and a small C++ class. It's not yet finished thought, still seem to have trouble with it.

I'm now working on the physical aspects of the work, trying to put everything together this week, playing with blowers, cables, glue and condoms.

I've worked much on the circuit for the "inflatable condoms" project. I've ran in so many problems. The biggest one is the electrical management. I had to fine tune the length and dynamics of the "heat release" process, that is, the part of the program where, when the sun sets, the blowers start to be activated.

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