Arduino

Arduino is an open-source hard­ware and soft­ware com­pany, pro­ject and user com­mu­nity that de­signs and man­u­fac­tures sin­gle-board mi­cro­con­trollers and mi­cro­con­troller kits for build­ing dig­i­tal de­vices. Text from Wikipedia

Projects built us­ing Arduino: