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  • Kandrix's instructable Wooden Fidget Hand Spinner under $1's weekly stats: 2 years ago
    • Wooden Fidget Hand Spinner under $1
      29,093 views
      140 favorites
      22 comments
  • Kandrix commented on Kandrix's instructable Wooden Fidget Hand Spinner under $12 years ago
    Wooden Fidget Hand Spinner under $1

    I've talked about that in step 2, sorry for not clear enogh instructions. But you can use anything you want really, if you stacked some washers of adequate size, it would work the same, or just take another nut and create hexagonal hole for it with precision file.

    Thanks for the tip, I appreciate any advice, as I'm fairly new to any woodworking.

    View Instructable »
  • Kandrix commented on Kandrix's instructable Wooden Fidget Hand Spinner under $12 years ago
    Wooden Fidget Hand Spinner under $1

    Thanks, I hope your son will like it.

    View Instructable »
  • DIY Portable Bluetooth Speaker 30W, BT4.0, Passive Radiators

    No, the math is correct. What I'm suspecting is that first - the amplifier board is capable of nowhere near 30 watt output. The "2*15w" way they call amps on ebay means most of the time nothing else that the amplifier is 15w total, not for two channels. According to the data speadsheet for the amplifier chip used (MAX9736A), it is capable of maximum output of 15 watts into 8ohm load with source voltage of 24volts. This output is when THD+N=10% (sh*tton of distortion). At 12 volts, with THD+N=1%, the maximum output for the chip is 8 watts into 8 ohm load. Those 8 watts are RMS, not continuous power. This means that this "30 watt speaker" is actually only 8 watts at best total, and I am not surprised by this value. These days, everyone is marketing their speakers as mu...

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    No, the math is correct. What I'm suspecting is that first - the amplifier board is capable of nowhere near 30 watt output. The "2*15w" way they call amps on ebay means most of the time nothing else that the amplifier is 15w total, not for two channels. According to the data speadsheet for the amplifier chip used (MAX9736A), it is capable of maximum output of 15 watts into 8ohm load with source voltage of 24volts. This output is when THD+N=10% (sh*tton of distortion). At 12 volts, with THD+N=1%, the maximum output for the chip is 8 watts into 8 ohm load. Those 8 watts are RMS, not continuous power. This means that this "30 watt speaker" is actually only 8 watts at best total, and I am not surprised by this value. These days, everyone is marketing their speakers as much higher wattage than their output really is (yes I blame JBL and similiar manufacturers). At best they market it with peak power being actual power of the device, which is not. If you saw a real 30 watt continous output from a speaker, it would definitely not look like this. This does by no means mean that it is not loud, damn my DIY (real continous 8W Yamaha PDX-B11) gets way louder than my friend's JBL Charge 3 which is marketed as "20W speaker"! You cannot cram such an wattage into so small speakers, thats just not how electronics and particularly speakers work. Again, judging by its battery, which is total of 22.2Wh, and marketed "20+ hour playtime" rating, this cannot last this time with more than a watt of power, with 100% efficient amplifier. You see now the bait? The company simply lies to people. Same with this speaker, which is by no means bad project, but "30w" is not something that this is.

    No, the math is correct. What I'm suspecting is that first - the amplifier board is capable of nowhere near 30 watt output. The "2*15w" way they call amps on ebay means most of the time nothing else that the amplifier is 15w total, not for two channels. According to the data speadsheet for the amplifier chip used (MAX9736A), it is capable of maximum output of 15 watts into 8ohm load with source voltage of 24volts. This output is when THD+N=10% (sh*tton of distortion). At 12 volts, with THD+N=1%, the maximum output for the chip is 8 watts into 8 ohm load. Those 8 watts are RMS, not continuous power. This means that this "30 watt speaker" is actually only 8 watts at best total, and I am not surprised by this value. These days, everyone is marketing their speakers as mu...

    see more »

    No, the math is correct. What I'm suspecting is that first - the amplifier board is capable of nowhere near 30 watt output. The "2*15w" way they call amps on ebay means most of the time nothing else that the amplifier is 15w total, not for two channels. According to the data speadsheet for the amplifier chip used (MAX9736A), it is capable of maximum output of 15 watts into 8ohm load with source voltage of 24volts. This output is when THD+N=10% (sh*tton of distortion). At 12 volts, with THD+N=1%, the maximum output for the chip is 8 watts into 8 ohm load. Those 8 watts are RMS, not continuous power. This means that this "30 watt speaker" is actually only 8 watts at best total, and I am not surprised by this value. These days, everyone is marketing their speakers as much higher wattage than their output really is (yes I blame JBL and similiar manufacturers). At best they market it with peak power being actual power of the device, which is not. If you saw a real 30 watt continous output from a speaker, it would definitely not look like this. This does by no means mean that it is not loud, damn my speaker (real continous 8W Yamaha PDX-B11) gets way louder than my friend's JBL Charge 3 which is marketed as "20W speaker"! You cannot cram such an wattage into so small speakers, thats just not how electronics and particularly speakers work. Again, judging by its battery, which is total of 22.2Wh, and marketed "20+ hour playtime" rating, this cannot last this time with more than a watt of power, with 100% efficient amplifier. You see now the bait? The company simply lies to people. Same with this speaker, which is by no means bad project, but "30w" is not something that this is.

    The amount of speakers doesn't matter at all. All what the amp sees is load resistance. If you put in 2x8ohm speakers in parallel, it sees it as one 4 ohm load. Also, putting them in series means 8+8ohm=16ohms. You can get a bit more output on lower ohm speaker, yet the quality depends highly on the amplifier, as 4 ohms are much more prone to interferences and hiss from low quality amps and wires. The total output wattage gets higher, but again, if the amp distorts at 10w and clipping occurs, it doesn't matter what the load is. If it can cleanly play 8w max, then its going to play 8w clean on both 4ohm( from parallel 8ohm) and 8ohm single driver, if you use proper wires to support the larger current that 4ohm might draw. Also amps that are designed for 8ohm do not always support 4ohm, o...

    see more »

    The amount of speakers doesn't matter at all. All what the amp sees is load resistance. If you put in 2x8ohm speakers in parallel, it sees it as one 4 ohm load. Also, putting them in series means 8+8ohm=16ohms. You can get a bit more output on lower ohm speaker, yet the quality depends highly on the amplifier, as 4 ohms are much more prone to interferences and hiss from low quality amps and wires. The total output wattage gets higher, but again, if the amp distorts at 10w and clipping occurs, it doesn't matter what the load is. If it can cleanly play 8w max, then its going to play 8w clean on both 4ohm( from parallel 8ohm) and 8ohm single driver, if you use proper wires to support the larger current that 4ohm might draw. Also amps that are designed for 8ohm do not always support 4ohm, or at least it might not be reccomended for them by manufacturer of the board.

    The amount of speakers doesn't matter at all. All what the driver sees is load resistance. If you put in 2x8ohm speakers in parallel, it sees it as one 4 ohm load. Also, putting them in series means 8+8ohm=16ohms. You can get a bit more output on lower ohm speaker, yet the quality depends highly on the amplifier, as 4 ohms are much more prone to interferences and hiss from low quality amps and wires. The total output wattage gets higher, but again, if the amp distorts at 10w and clipping occurs, it doesn't matter what the load is. If it can cleanly play 8w max, then its going to play 8w clean on both 4ohm( from parallel 8ohm) and 8ohm single driver, if you use proper wires to support the larger current that 4ohm might draw. Also amps that are designed for 8ohm do not always support 4ohm...

    see more »

    The amount of speakers doesn't matter at all. All what the driver sees is load resistance. If you put in 2x8ohm speakers in parallel, it sees it as one 4 ohm load. Also, putting them in series means 8+8ohm=16ohms. You can get a bit more output on lower ohm speaker, yet the quality depends highly on the amplifier, as 4 ohms are much more prone to interferences and hiss from low quality amps and wires. The total output wattage gets higher, but again, if the amp distorts at 10w and clipping occurs, it doesn't matter what the load is. If it can cleanly play 8w max, then its going to play 8w clean on both 4ohm( from parallel 8ohm) and 8ohm single driver, if you use proper wires to support the larger current that 4ohm might draw. Also amps that are designed for 8ohm do not always support 4ohm, or at least it might not be reccomended for them by manufacturer of the board.

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  • Kandrix commented on kenyer's instructable Fidget toy hand spinner2 years ago
    Fidget toy hand spinner

    Cool! Got my ball bearings ordered. Did you use PLA or ABS for the print? :-)

    View Instructable »
  • DIY Portable Bluetooth Speaker 30W, BT4.0, Passive Radiators

    Very basic math. First, take your 18650s. They're nominal 3.7 volts, 4.2volts at full charge and 3v fully discharged. Most of them are 2.2Ah-2.6Ah. Don't be fooled by those "5000mAh" ones on ebay. Best you can get (and also very expensive) are panasonics 3200mAh. They used to make 3400mAh as well, but stopped then. Anything bigger in capacity and I would be extremly suspicious. Just google for measured and empiric values for each model. That gives us for example for single 186503.7v * 2.2Ah = 8,14 watt-hoursThat means single 18650 could run 1w speaker for 8,14hours, or 8,14w speaker for an hour.I suppose this gives you all the math neccessary for your project. Happy building :)(last word: Don't get scared if your big project needs alot of juice, I've even used 15x 18650 batter...

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    Very basic math. First, take your 18650s. They're nominal 3.7 volts, 4.2volts at full charge and 3v fully discharged. Most of them are 2.2Ah-2.6Ah. Don't be fooled by those "5000mAh" ones on ebay. Best you can get (and also very expensive) are panasonics 3200mAh. They used to make 3400mAh as well, but stopped then. Anything bigger in capacity and I would be extremly suspicious. Just google for measured and empiric values for each model. That gives us for example for single 186503.7v * 2.2Ah = 8,14 watt-hoursThat means single 18650 could run 1w speaker for 8,14hours, or 8,14w speaker for an hour.I suppose this gives you all the math neccessary for your project. Happy building :)(last word: Don't get scared if your big project needs alot of juice, I've even used 15x 18650 batteries in my handheld floodlight, which you could find with detailed guide on my instructables profile.)

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  • Easy 5 Minutes USB Solar Charger/Survival USB Charger

    Nice idea mate, but there are a few things to consider before building this. First of all, just for those of you in comments that suggested 7805 ICs, educate yourselves about boost/buck converters. That being said, average efficiency of those "car charger" ones would be anywhere between 80-90%. The solar panel you're using is made to supply 1 watt AT LAB CONDITIONS, thats how they're certified. That means proper light intensity, and perpendicular to the sunbeams. Anything less, and output drops even below half of that certified. Minus efficiency of the converter, minus efficiency of the charging circuitry in your phone that feeds the Li-Ion 3,7v battery with 4,2v from a 5v source. Quick calculation:At best possible conditions with highly efficient converters:1w * 0,9 * 0,9 = 0...

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    Nice idea mate, but there are a few things to consider before building this. First of all, just for those of you in comments that suggested 7805 ICs, educate yourselves about boost/buck converters. That being said, average efficiency of those "car charger" ones would be anywhere between 80-90%. The solar panel you're using is made to supply 1 watt AT LAB CONDITIONS, thats how they're certified. That means proper light intensity, and perpendicular to the sunbeams. Anything less, and output drops even below half of that certified. Minus efficiency of the converter, minus efficiency of the charging circuitry in your phone that feeds the Li-Ion 3,7v battery with 4,2v from a 5v source. Quick calculation:At best possible conditions with highly efficient converters:1w * 0,9 * 0,9 = 0,81 watts of usable electricity. Can light charging diode, but charge the phone fully? Nah, probably not. Why?Reference, Galaxy s5 battery. 2100mAh, Li-Ion, full at 4,2v, discharged at 3,5v, nominal V 3.7v.2.1*3.7= 7.77 Watt-hours7,77/0,81 = 9,59 hours of charging time, in ideal conditions. Good sun to keep stable 1w off this panel could be found on... Sahara desert?More realistic would be anything between 0,3-0,6 watts, according to "ebay cheapo solar power bank review" videos on youtube. What that means? Anywhere between 20-30 hours of charging time in perfect midday sun... So the phone loses charge almost as fast as its getting it. By this I mean no offense, just reccomendation, as a person who's been DIYing with solar stuff for quite some time, it you want to charge anything with solar panel, size of the panel matters the most. If your phone's wall charger is 5watt, get at least twice that as solar panel, as sun never really gives us those perfect lab conditions. Many successes with following projects! :-)

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