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grendell

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11CommentsSurrey, England

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  • grendell commented on educ8s's instructable Internet Radio Using an ESP321 year ago
    Internet Radio Using an ESP32

    Excellent project. Your audio noise could be due to the routing of the 0v line. For audio the suggestion is to use a single point for the 0v not a long linear bus. You could also try adding a 100uf 16v capacitor across the 5v rail with a 0.1uf ceramic capacitor in parallel. A possible improvement to the software I would like would be the ability to input the WiFi details so the radio can be used in several locations but I can see that would complicate things!

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  • grendell commented on Maker Gray's instructable DIY Ikea Butcher Block Countertops1 year ago
    DIY Ikea Butcher Block Countertops

    Interesting project.I have similar wooden counter tops which are in desperateneed of renovation. Your finish looks excellent but I would be interested to hear how the finish is holding up to every daykitchen use. I was advised to use a 2 part lacquer intended for wooden floorprotection but even this would not be heat proof.G

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  • grendell commented on ThomasH358's instructable Battery Powered Tube Amplifier1 year ago
    Battery Powered Tube Amplifier

    Quite apart from the project itself and the amount of time you spent on producing this excellent instructable, I must compliment you on taking the time to answer the various comments that people post. So many people seem to post an article and that's it. I think you should get an award just for commitment to your readers!.Graham

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  • DIY Grid Tied Inverter (doesn't Feed the Grid) UPS Alternative

    Hi there,Not sure I agree with your comments about high frequency inverter only for supplying power to limited devices for a short periods. What about double conversion UPSs where the load is fed 100% of the time from the HF "inverter" and only the input source transfers from grid to battery?G

    Good resource showing what items are available these days. One point on the ATS. I understand it isolates line and neural (hot and cold). On the inverter, is the neutral tied to the earth (ground)? I have done a bit of work with UPSs and had problems when switching back to grid power as the UPS did not have a neutral ground link. The problem is that a lot of kit has input filters which, in addition to inductors, have capacitors L-E and N-E. If the UPS is not referenced to ground both legs can float 120-0-120 (on a 240v system). No problem there at all. However, if you now switch back to the grid you have a load of N-E input capacitors which can be charged up which will discharge via the utility N-E link. The result is that standard RCDs (GFIs) can trip. If anyone has this issue, try us...

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    Good resource showing what items are available these days. One point on the ATS. I understand it isolates line and neural (hot and cold). On the inverter, is the neutral tied to the earth (ground)? I have done a bit of work with UPSs and had problems when switching back to grid power as the UPS did not have a neutral ground link. The problem is that a lot of kit has input filters which, in addition to inductors, have capacitors L-E and N-E. If the UPS is not referenced to ground both legs can float 120-0-120 (on a 240v system). No problem there at all. However, if you now switch back to the grid you have a load of N-E input capacitors which can be charged up which will discharge via the utility N-E link. The result is that standard RCDs (GFIs) can trip. If anyone has this issue, try using a time delay RCD to overcome this.G

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  • grendell followed Kieren-J1 year ago
      • DIY Grid Tied Inverter (doesn't Feed the Grid) UPS Alternative
      • DIY Grid Tied Inverter (using UPS)
  • Connecting Arduino With Temboo and Read Email

    Thanks for this. I did get it going after a few attempts!As pointed out the free plan expires every month unless you take out a subscription. Update 2017. It seems Temboo have abandoned their "Individual plan" earlier this year which was $7 US a month and now only have a plan costing over $450 US a year!I am now looking at using a GSM card to send an SMS to a free SMS to email service. More up front hardware cost but cheaper than $450 per year.GTemboo

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  • grendell commented on thediylife's instructable Simple Arduino Home Energy Meter3 years ago
    Simple Arduino Home Energy Meter

    Hi,Yes the CT does produce an AC voltage. This could be fed to an RMS convertor chip to produce a DC voltage, however the arrangement here is to bias one leg of the CT to 2.5v DC and let the other leg swing either side of 2.5v (but not above 5v or below zero). In this simple setup the "RMS" is assumed to be 0.707x the peak values.

    HiCongratulations on a simple introduction to electricitymetering. I too have been looking at various complicated solutions on theinternet but would certainly look to build this as a starting point.As a matter of interest, how close are your results to yourcompany meter over say a month? I would suggest, having compared the resultsfor a while you could always alter the value of the fixed “voltage” (220) up ordown to bring the results closer to each other which would compensate for yourlocal supply voltage and the average power factor for your house.Another thought in regard to the ½ reference divider, couldyou not use another analogue input to read this “fixed” value from time to timeand use that value for the subtraction? Also I am not clear as to what th...

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    HiCongratulations on a simple introduction to electricitymetering. I too have been looking at various complicated solutions on theinternet but would certainly look to build this as a starting point.As a matter of interest, how close are your results to yourcompany meter over say a month? I would suggest, having compared the resultsfor a while you could always alter the value of the fixed “voltage” (220) up ordown to bring the results closer to each other which would compensate for yourlocal supply voltage and the average power factor for your house.Another thought in regard to the ½ reference divider, couldyou not use another analogue input to read this “fixed” value from time to timeand use that value for the subtraction? Also I am not clear as to what the … if(maxCurrent <= 517)…. is needed for- does this correct for no load drift?Finally to be a little pedantic, I think you should not usethe label peakPower as that could be confusing, rather use maxPower. JoergeliI love your display for energy usage. Any chance of an Instructable(in English!) to show how it is done?G

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  • grendell commented on StephanP1's instructable Ingeniously simple mousetrap3 years ago
    Ingeniously simple mousetrap

    I was wondering what the big knife was for at the start of your video!Also, peanut butter I find works well too.G

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  • How to Make a Pure Black Photography Background!

    I think you are having trouble shooting on a whitebackground because the camera is on auto exposure.Most cameras assume the overall average reflectance of the sceneis 18% of the whitest area. If you shoot a small object on a big white card thecamera will adjust the average brightness down so the white becomes grey as thecamera will under expose.There are several options to correct this. Check if you camerahas Back Light Compensation. If it does see if you can set it to plus 2 ½ stops.This will fool the camera to overexpose which should bring the white back towhite.Another option is to see if your camera has Spot Metering.This masks the cameras metering area to a spot, usually in the centre thisignoring the white background but correctly exposing your item of interest.If you have ...

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    I think you are having trouble shooting on a whitebackground because the camera is on auto exposure.Most cameras assume the overall average reflectance of the sceneis 18% of the whitest area. If you shoot a small object on a big white card thecamera will adjust the average brightness down so the white becomes grey as thecamera will under expose.There are several options to correct this. Check if you camerahas Back Light Compensation. If it does see if you can set it to plus 2 ½ stops.This will fool the camera to overexpose which should bring the white back towhite.Another option is to see if your camera has Spot Metering.This masks the cameras metering area to a spot, usually in the centre thisignoring the white background but correctly exposing your item of interest.If you have no adjustments your camera may be able to lockits exposure by partly pressing the shutter button.You will need a tripod. A good photographicsupplier should be able to sell you an 18% grey card. Hold the bard behind youritem with one hand, partly depress the shutter to lock the exposure (and focus) then remove the grey card and fully press the shutter. then remove the grey card and fully press the shutter.

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  • Arduino Email Sender with Ethernet adapter/shield

    Hi there,Many thanks for your time in producing this guide. I am not clear though, will this only send a preset message? I am looking to send at least one vairable number such as " The current temp is" 123 "c" and may be date and time as well. I intend to use a RTC to send the email once a day so could add the date / time to the email.

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