Bluetooth temperature module

Wanting to know the outside temperature, [Jamie Maloway] built his own temperature sensor that can be read with a Bluetooth device. Let’s take a tour of the hardware above from right to left. There’s a linear voltage regulator with two filtering caps and a terminal block to attach a 9V battery or other power source. Next there’s an 8 MHz crystal and it’s capacitors, followed by a programming header on top and a 1-wire temperature IC, the DS18B20 we’re all familiar with hanging off the bottom. These both connect to the 8-pin PIC 12F675 that drives the system, and transmits using a Bluetooth module from Sure Electronics. Since this is using a serial protocol and transmitting ASCII data, it can be read using an automated script, or simply by using a terminal program.

Now, who’s going to be the first to get rid of the battery and leech off of the mains through inductance?

Miniscule intervalometer

Calling this intervalomemter small would be a glaring understatement. It’s tiny enough to fit inside the plastic cover for a 2.5mm jack for use with a Canon DSLR camera. We should point out that the image we put together is a bit misleading. The picture of the jack is version 1 of this circuit and uses an 8-pin SOIC chip. The board in the oval is version 2, with a PIC 10f222 SOT23-6 package making it even smaller than the original version.

This is used for time-lapse photography. When plugged in the chip draws power from the camera. Get this: it learns the timing interval by listening for the first two images. Once you’ve snapped the first two pictures the PIC will continue to take images based on that initial delay. Amazing.

[Thanks AW via DIY Photography]


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