Carl Nordblom made a nice looking construction for the bells using leaf springs.
An ESP8266 is listening on some bell topics for messages. If a message is received it will swing the corresponding servo with a bell hooked up.
To trigger the bells we built a box with a auto returning string to pull. The strings is hooked up to a micro switch witch triggers the reset pin on a ESP8266.
When the ESP8266 starts it sends a message on the corresponding MQTT topic to ring, then enter heavy sleep mode.
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A micro switch will cut the power to an MP3-player module will built in amplifier when it’s folded.
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The solar panels worked really great, we had no trouble at all and the LiPo was charged nicely.
We did use an old Sennheiser wireless transmitter to send the audio from the DJ-booth at Festmaskinen to the PA-speakers at CyckelLjudet.
We had some problems with wireless interference, but it hold up well most of the parade. Go 80’s technology!
To be able to drive the amplifier for the speaker we use an UPS. On top of the UPS you can see the solar regulator Solar80.
The solar regulator is charging a 6S 8Ah LiPo battery pack. The solar panels will generate maximum of 600W of power, and the PA-system will draw about 65W of power, so the battery will be more of a buffer.
After some spec-readings we realized that the Solar80 wouldn’t handle the maximum of 70V that the solar panels could generate, it only supported 48V. So we switched it out for Flexmax 80.
Both the controllers were designed for lead-acid battery’s and not for LiPo battery’s. I was missing a parameter to set the charge voltage, also there was software limitations that you couldn’t go around, like the charging current for example, you could only go as low as 5A.
We’re trying out the solar panels and solar regulator in the sun charging the LiPo. The stop-charing-limit was set to 25.2V which is the voltage of a maximum charged LiPo, but the solar regulator was still inputing voltage well above 25.2V because the solar regulator is designed for lead acid battery’s. We then set the maximum-charging-voltage to 24.8V that seemed to help, the voltage over the battery didn’t reached over 25.2V.