For all not having a network of suppliers, ordering all the parts can be a little bit painful. At least in germany I didn’t find a supplier having all parts even for this simple project. Then some of the professional suppliers refuse to sell to private persons. And if they do, they add additional cost for small orders. Ok, at least that is understandable. Electronic suppliers for private business like conrad.de or reichelt.de on the other side have higher prices per piece.

The main costs of the sensor are produced by only a few components. The hall sensor is clearly outstanding and probably the reason why many sensors rely on a shunt resistor solution. You get the sensor from farnell.com or a partner selling to private persons like hbe-shop.de. The BMP180 and many other parts can be order for a good price at mouser.de.

Here you get a list of the main parts and a possible supplier. All other parts are available by all of them (and will cost 2€ in total).