here is a flow to get voltage from arduino A1 using cheap voltage sensor ..
Code:
[{"id":"bbc427fe.5a5808","type":"debug","z":"217cab7.d842f54","name":"","active":true,"console":"false","complete":"payload","x":690,"y":500,"wires":[]},{"id":"13174b93.baafe4","type":"arduino in","z":"217cab7.d842f54","name":"house","pin":"1","state":"ANALOG","arduino":"46c1ac0.3d81c54","x":70,"y":500,"wires":[["6554aea5.2ed24"]]},{"id":"6554aea5.2ed24","type":"function","z":"217cab7.d842f54","name":"","func":"\nvar vout = 0.0;\nvar vin = 0.0;\nvar R1 = 30000.0;\nvar R2 = 7500.0; \nvar value= msg.payload;\n\n\n vout = (value * 5.0) / 1024.0; \n vin = vout / (R2/(R1+R2)); \n \nvin.toFixed(1);\n\nmsg.payload=vin;\n\nreturn msg;","outputs":1,"noerr":0,"x":210,"y":500,"wires":[["fd8bf893.fad638"]]},{"id":"c825b564.a05688","type":"ui_template","z":"217cab7.d842f54","group":"d892bd84.4ab9","name":"house","order":1,"width":"4","height":"4","format":"<script src=\"/myjs/tween-min.js\"></script>\n<script src=\"/myjs/steelseries-min.js\"></script>\n<script>\nvar test;\n (function(scope){ \n scope.$watch('msg', function(msg) {\n if (typeof(msg.value) != \"undefined\") test.setValueAnimated(msg.value);\n //if (typeof(msg.threshold) != \"undefined\") radial4.setThreshold(msg.threshold);\n // if (typeof(msg.odo) != \"undefined\")radial4.setOdoValue(msg.odo); \n //if (typeof(msg.userLed) != \"undefined\") radial4.setUserLedOnOff(msg.userLed); \n // if (typeof(msg.trend) != \"undefined\")\n {\n // if (msg.trend==1) radial4.setTrend(steelseries.TrendState.UP);\n //if (msg.trend==0) radial4.setTrend(steelseries.TrendState.STEADY);\n // if (msg.trend==-1) radial4.setTrend(steelseries.TrendState.DOWN);\n // if (msg.trend==-2) radial4.setTrend(steelseries.TrendState.OFF);\n }\n });\n })(scope);\n\n var sections = [steelseries.Section(0, 25, 'rgba(0, 0, 220, 0.3)'),\n steelseries.Section(25, 50, 'rgba(0, 220, 0, 0.3)'),\n steelseries.Section(50, 75, 'rgba(220, 220, 0, 0.3)') ],\n\n // Define one area\n areas = [steelseries.Section(75, 100, 'rgba(220, 0, 0, 0.3)')],\n\n test = new steelseries.Radial('test', {\n gaugeType: steelseries.GaugeType.TYPE2,\n size: 190,\n section: sections,\n area: areas,\n titleString: \"House\",\n unitString: \"VOLTS\",\n threshold: 11.9,\n minValue: 0,\n maxValue: 18,\n thresholdRising: false,\n //userLedVisible: true,\n // useOdometer: true,\n lcdVisible: true,\n // trendVisible: true\n });\n \n \n test.setFrameDesign(steelseries.FrameDesign.BRASS);\n test.setValueAnimated(0);\n test.setPointerType(steelseries.PointerType.TYPE9);\n //test.minValue =(0),\n //test.maxValue =(24),\n // radial4.setThreshold(50);\n //radial4.blinkUserLed(0);\n // radial4.setOdoValue(0);\n\n\n</script>\n\n<canvas id=\"test\" width=\"190\" height=\"190\"></canvas>\n","storeOutMessages":false,"fwdInMessages":true,"x":490,"y":500,"wires":[["bbc427fe.5a5808"]]},{"id":"fd8bf893.fad638","type":"function","z":"217cab7.d842f54","name":"","func":"msg.value=msg.payload;\nreturn msg;","outputs":1,"noerr":0,"x":330,"y":500,"wires":[["c825b564.a05688","7e3550ac.04a2d"]]},{"id":"7e3550ac.04a2d","type":"ui_gauge","z":"217cab7.d842f54","name":"","group":"d892bd84.4ab9","order":0,"width":0,"height":0,"gtype":"gage","title":"Gauge","label":"units","format":"{{value}}","min":0,"max":"18","colors":["#00b500","#e6e600","#ca3838"],"seg1":"","seg2":"","x":488,"y":461,"wires":[]},{"id":"46c1ac0.3d81c54","type":"arduino-board","z":"","device":"/dev/ttyACM0"},{"id":"d892bd84.4ab9","type":"ui_group","z":"","name":"compass","tab":"bdb776e4.17a1e8","order":1,"disp":true,"width":"6"},{"id":"bdb776e4.17a1e8","type":"ui_tab","z":"","name":"Home","icon":"dashboard"}]