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Showing posts with the label wemos

Upgraded Heat Exchanger Control System

 Speed Control added to ERV heat exchanger fans and a recirculation/bypass valve between the inlet and exhaust fan. Flower pots hot glue and tie wraps the corner stone of any ventilation system.  Its a throttle valve in a manifold between the inlet and exhaust fan plenums. Fan speed is set using the existing Wemos D1 R2 which can output 25Khz accurately to drive the PWM fan speed demand signal. Code changes to the ERV DAS and the ERV Controller and related Hubitat drivers, now renamed,  Ventilation Controller as it manages the boost fans for the zones. Drivers Some testing with no pipes connected showing the blockage effect of the heat exchanger core Exhaust fan only recirculate open 100%

EV Charger

Alexa Integration   Circuit Design We made an EVSE from parts on Banggood & Aliexpress mostly 16A 3.7 kW EV charging controller board + Type 1 EV  Current Sensor This is the key component for controlling charge level and auto shut off at the end of the charge. Probably saves a wee bit of energy with the power to the EVSE disconected in the off state also. Irms = emon1.calcIrms( 1480 ); // Calculate Irms only Kw = (Irms * 230.0 ) / 1000.0 ; float hours = (millis() - lastMillis) / ( 1000.0 * 3600.0 ) ; TotalChargeHours += hours; lastMillis = millis(); //CALC KWH if ( abs (Kw) > 0.1 ) KWh += (Kw * hours); Note: You must add a suitable burden resistor if one is not on the CT board already or the high voltage will damage the Arduino. The one shown has a burden resistor. PCB size 30.0mm X 24.0mm X 1.6mm Compatible interfaces 2.54 3-pin interface and 4-pin Grove interface Transformation coefficient 1000:1 Input current 0 - 5 A Output current 0 - 5 mA Sa