DigitalExperience

To give more meaning to the trip at the pub just take with you two barometric pressure sensor and see what happens. While Quake thinks about a pretty bartender the dongle keeps logging. Infineon DPS310 and Rohm BM1383AGLV are both small i2c chip, sampled every second, same 8 values build in average enabled. For comparison a GPS track was recorded too and the elevation graphed along side.

graph.png

(continue reading…)

There are a lot of different magnetic reed switches but by far the more common is the normally open version. Normally it’s on open circuit that closes when you put a magnet near it, and the led shines. The north-south axis of the magnet should be parallel to the axis of the reed and placed near the center.

One day I needed one that acted the opposite way: Normally it must be a closed circuit that opens when a magnet comes near. You can buy it right away but i didn’t want to wait.

By placing a second magnet oriented the opposite way the switch opens because it cancel out the magnetic field in the middle. So one magnet must be fixed to close the switch and when the other magnet comes near, it cancel the field and open the switch. Day saved. Zaion.

Sometime a button on your remote controller stop working and so you need to fix it. Usually there is nothing really broken, just the rubber conductive pad are worn out and no longer close the circuit.

I tried with some graphite powder but it’s not long lasting. Gluing a square aluminium foil on top is difficult because you need to have the right adhesive otherwise it will fall out.

The solution was to use a mechanical way to secure some conductive material, in this case I pocked two holes under the pad with a needle and then threaded in a thin copper wire. It really is simple and reliable. Zaion.

The Raspberry, a pretty interesting piece of hardware (half micro controller, half computer), is here used as a temperature sampler (via I2C sensor). The data collected is then employed  to draw a graph and send it to your e-mail account using wifi connection. All this is performed using only some useful open programs and a little bash scripting.

(continue reading…)

Appena è arrivato il mio Raspberry-PI non vedevo l’ora di provarlo e giocarci ma solamente accenderlo si è rivelato più complicato del previsto.
Per evitare i comuni problemi di alimentazione ho alimentato il mio raspberry tramite i GPIO con un alimentatore ATX. Tensione ben stabilizzata e tanta corrente a disposizione (Oltre alla protezione da corto).
Ho acceso la scheda e ho provato a configurare una chiavetta wifi per potermi connettere da remoto. Il sistema operativo l’ha subito riconosciuta, caricato i driver e aggiunto la periferica. Ho configurato i parametri per connettermi al mio Access Point ma non ne voleva sapere di funzionare. Il listing delle reti rilevate funzionava saltuariamente e le poche volte che riuscivo a connettermi si sconnetteva da solo subito dopo lasciando questo strano messaggio su dmesg:

(continue reading…)