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Tripping a 20A breaker

Hello. I need help with charging a capacitor bank I have. It consists of 10 capacitors: 4 4700uf capacitors and 6 6800uf capacitors. All are wired in parallel. I have been charging them with 110AC rectified to DC. The only problem is that whenever I flip the switch to start charging, it trips our shop's 20A breaker and you have to flip it back to start charging again. It trips our breaker every time and dims the lights making my dad angry. So I need some tips on what wattage resistor i need to use to keep from tripping the breaker. I experimented with a 10W resistor and that was way too much resistance. I am not allowed to experiment anymore until someone credible can tell me what to do. Thanks for your help.

Topic by tinstructable    |  last reply


14-16V to 12V stable 20A max

Hi,I am looking at stepping down from (14 to 16V) to 12V drawing at max 20Ais there any efficient way to do so in a very very small package?Thank you

Topic by garnio    |  last reply


Universal stepper motor controller

I wanted to create a universal stepper driver that is capable of driving a stepper of 250w rating at 20A current and a load voltage of 12V . Does anybody have an idea of how to go about it ? . Please do guide me if you have any ideas .  Also this drive should be capable of being used for bipolar as well as universal stepper motors.

Topic by arjunv8    |  last reply


Tripping a Breaker

Hello. I need help with charging a capacitor bank I have. It consists of 10 capacitors: 4 4700uf capacitors and 6 6800uf capacitors. All are wired in parallel. I have been charging them with 110AC rectified to DC. The only problem is that whenever I flip the switch to start charging, it trips our shop's 20A breaker and you have to flip it back to start charging again. It trips our breaker every time and dims the lights making my dad angry. So I need some tips on what wattage resistor i need to use to keep from tripping the breaker. I experimented with a 10W resistor and that was way too much resistance. I am not allowed to experiment anymore until someone credible can tell me what to do. Thanks for your help.

Topic by tinstructable    |  last reply


Help Charging my Capacitor Bank Without Tripping The Breaker.

Hello. I need help with charging a capacitor bank I have. It consists of 10 capacitors: 4 4700uf capacitors and 6 6800uf capacitors. All are wired in parallel. I have been charging them with 110AC rectified to DC. The only problem is that whenever I flip the switch to start charging, it trips our shop's 20A breaker and you have to flip it back to start charging again. It trips our breaker every time and dims the lights making my dad angry. So I need some tips on what wattage resistor i need to use to keep from tripping the breaker. I experimented with a 10W resistor and that was way too much resistance. I am not allowed to experiment anymore until someone credible can tell me what to do. Thanks for your help.

Topic by tinstructable    |  last reply


Anyone know where I could acquire a 120VAC-24VDC converter that outputs ~20A? Answered

Preferably at a price that doesn't break the bank.  I've been thinking about setting up a UPS for a robot that I'm working on, and 20A should be a bit higher than the amount of current that it would draw when up on jacks.

Question by killersquirel11    |  last reply



USB power cooling fan?

Can my laptops usb port power a 12v .20A cooling fan if i hard wired it? I know it would be under powered, but it shouldnt harm my computer right?

Question by clayton993    |  last reply


Regarding motor controller selection.

I need a motor controller for 24V, 20A Actuator. The motor controllers receive 16V from battery and also had to boost the voltage to meet actuator specifications. Can anyone help me finding a motor controller of such sort?

Topic by GamanM  


solid state relays

I have four, 5A, 280V solid state relays. They are activated by 3-8V. I need to tie them together so that I end up with a total of 20A. Do I tie them in series, or parallel? Also, do I tie the inputs in series or parallel so that there is one input? Thanks.

Topic by gimmelotsarobots    |  last reply


I have a three phase power point in my room (500V, 20A, 50Hz ) whats some cool stuff I can make and plug into it?

Preferably something I can make cheep. I have some experiance with electronics(3rd year optoelectronics at uni) but no experience with much more than 1A and 30V circuits.

Question    |  last reply


switch for a coilgun Answered

What is the minimum amperage rating needed for the fire switch and what will happen if u use something lower, like a 20a light switch? also how much one would cost would be nice to. i have heard that 40 or 50 A will work, but i would like to use something smaller, easyer to find, and more affordable. any help would be nice.

Question by the mechanical engineer    |  last reply


are these sufficient specs for a multimeter?

These are the specs off a multimeter im about to buy. are these enough to do electronic projects off instructables.com, fixing electronics, and etc? if not then what do i need then? thanks DC Voltage: 200mV-1000V AC Voltage: 2V-700V Temperature: 20°-1000°C Resistance: 200Ω-20MΩ DC Current: 2mA-20A AC Current: 20mA-200mA Capacitance: 2nF-20µF Frequency: 10Hz-20kHz  

Topic by leader1    |  last reply


What flyback diode should I use for my spark gap transmitter?

The power is a 12V car battery ( I think 20A) and I have a car ignition coil with an output of 45kV.  I want to use a 555 for the interrupter and wondering how to size the flyback diode to protect the circuit.  I have limited knowledge of circuitry and trying not to electrocute myself!thanks!

Question by dennis.ostrem.5  


Motor Driver IC Blown up. Wish to know what went wrong

I am using 11.1V 25C 3700mAh Lipo Battery for powering up Motor driver Card (Dual DC Motor Driver 20A) Motor driver Product Link: http://robokits.co.in/motor-drives/dual-dc-motor-driver-20a . Basically, I tried connecting two motors instead of single Motor on each motor port on the driver. So in all 4 DC motors connected as the motors had no load. As per my calculations, all 4 DC motors together cannot draw more than 4 Amps of current. DC Motor Specifications 10 RPM High Torque Dc Motor. Link : http://robokits.co.in/motors/high-torque-dc-geared-motor-10rpm?cPath=2_3& During this check I noticed that one of the IC LR 7843 on the motor Driver Card got burnt, the moment I powered it up with LiPo Battery. Really don't Know why this happened.... Can someone please help me....

Topic by iaf64    |  last reply


Does anyone have any ideas on how to build a simple but reliable motor controller for a high voltage (500v) DC motor?

I need to make a high voltage (500V), high current (20A) DC motor controller that uses a DC power source. It must be reliable and last a long time, and it also needs to be able control the speed of the motor from zero and up. Any ideas on building one or perhaps one that I can buy? Thanks!

Question by ANDY!    |  last reply


Operating a transformer at half the voltage? Answered

What could be the effects of the output when operating a transformer at half its rated voltage, specifically to the amperage? as two examples: If I had a transformer rated for an input of 240v and an output of 20A at 24v and I was to supply the primary with 120v, what would happen to the output? If I had a variac (autotransformer, variable transformer, ect.) and it was rated for an input of 240v with an output of 0-260v at 11A, what would happen to the output ratings at only 120v?

Question by pmk222    |  last reply


looking for a component to control my 36v500w motor speed and direction from an arduino

Hello! I am currently trying to build my won electric scooter. i bought this motor http://www.ebay.com/itm/Razor-MX500-Dirt-Rocket-Bike-Electric-Scooter-Motor-36V-500W-MY1020-P-ST20-/141293042627?pt=Motors_ATV_Parts_Accessories&hash;=item20e5b8bbc3&vxp;=mtr and i have a 38v 10A battery which i plan on turning into 20A further more i plan on using a resistor to change the out volt to 36v. i am now looking for a controller that i can connect to an arduino so the arduino can control the speed and direction of the motor. any suggestions?

Question by bfeher1    |  last reply


What rectifier should i use?

I have a snowmobile engine in a golf cart, and want to charge the golf cart battery. the snowmobile engine has a stator already for powering the headlight. But the headlight ran on 12v ac. so i need to install a rectifier. Im guessing im going to be working with 20A or so, and it will be charging a battery about the size of your average lawnmower battery. What rectifier should i get that can handle the amperage it would take too charge the battery? The engine already has a regulator, so i will just run the rectifier from the headlight wiring harness because it is getting the regulated 12v.

Question by robotman36    |  last reply


Can I replace the transistors in this LM723 regulator circuit with MOSFETs? Answered

I am trying to build a power supply capable of outputting up to 15V at 10A. The heatsinks I have are not suitable to use with the 2n3005s TO-204 case. Also I can get IRFP250 MOSFETs a lot cheaper. The transistors I want to replace are Q2-Q4, Q5 I will not include because I only want 3 FETs because I only want a 10A supply not a 20A.  Here's the link: http://www.thebackshed.com/forum/forum_posts.asp?TID=2249&PN;=2&TPN;=1http://www.thebackshed.com/forum/forum_posts.asp?TID=2249&PN;=2&TPN;=1

Question by The MadScientist    |  last reply


how to power multiple fans from a laptop? Answered

I'm currently working on a laptop to somewhat of a desktop conversion.  The laptop has really bad cooling so i have drilled into the case and added some big fans.  Its probably overkill yes, but if it works then who cares.   I've added two fans.  One is a 24V DC .20A fan and the other is a regular DC motor.  I'm wanting to power them from the laptop.  I'm not sure how to do that though.  I've tested them both separately on a USB and they are very slow and almost useless.  Is there a way to combine two USB ports for more juice?  Any ideas or suggestions?  Thanks.

Question by knex.gun.builder    |  last reply


Can you build a pmdc motor that can pull a skateboard prety fast on 240W?

I'm trying to build a pmdc motor (perminent magnet motor) based on this video: https://www.youtube.com/watch?v=WKklyuzghQg But I want to make it in a much biger scale and instead of using a ceramic magnet I wan to use 2 big industrial neodymium magnets instead they will pull up to 200 pounds. I want this homemade built motor to pull a scooter like vehicle (skateboard if you will). It will be powerd by 2 12V 10A batteries wich doing the math should get me: 12V+12V=24V 10A+10A=20A 24Vx20A=240W The coils will be made from 1.5mm thick copper wire. Based on what I've said do you think the motor could be powerful enough to pull this scooter with someone standing on it at about 20 to 25mph? can this be done?

Topic by NoahW7    |  last reply


Info about Cockroft-Walton generator (multiplier). Answered

I'm making Cockroft-Walton generators again after some time and some problems I had, and I would like to ask some questions I couldn't answer by myself so I don't end breaking this new one I'm making. Is it bad to run the multiplier with the sole intention of making arcs? Could the discharge end damaging the diodes? I've been running the ones I created with UF4007 diodes, which have a peak amperage of 30A, now I'm using two BA159 in series (so I can set the voltage up to 2kV), they have a peak amperage of 20A. If yes I guess there's no easy solution for this, other than to reduce the discharge current or get beefier diodes. Regarding to the previous question, does the whole capacitor array discharges when an arc strikes, or just the last/lasts one/ones? Thanks for your time.

Question by Victor805    |  last reply


Help me with my 3D printer

ISSUE: Stepper motors are not working when connected with RAMPS 1.4.OBSERVATION: The LED lights(LED 2,3,4) in the RAMPS 1.4 and Stepper motor are not powering up.PRATICES: I use Arduino mega 2560 and installed marlin firmware in it. And I bought a RAMPS 1.4 in a local electronic dealer. I placed the RAMPS over Arduino mega 2560. For testing I just connected 2 NEMA 17 stepper motors with RAMPS. When USB port connection is given from laptop to arudino board, a LED light is ON in Arduino board(L) and in RAMPS(LED 1). I use SMPS 12V 20A as a PSU for RAMPS. But in RAMPS the LED 2,3,4 is not switched ON. I checked the input voltage to the RAMPS using micrometer and it shows 11.75V. But there is no output from the RAMPS.Also I installed and tried Repetier firmware and grbl but it doesn't work.When I flashed Arduino with grbl, in this case all the LED lights in arduino and RAMPS 1.4 is switch ON. I use Candle GRBL software to test the stepper motors.And I replaced and tested with another RAMPS which is bought from Amazon but the problem remains unchanged.Hereby I attached images of circuit connections. https://i.imgur.com/mM3BIEn.jpg https://i.imgur.com/OPPuElQ.jpg https://i.imgur.com/mM3BIEn.jpg kindly give some suggestions at the earliest.Thanks and regardsBaalaji V

Question by Baalaji V  


Replace just 1-2 bad li-on cells?

I've got a fairly new DeWalt 20V Lipo Battery pack that got a bit of water inside it's case, causing 1 of the 10 cells inside to go bad. Pertinent info: * Battery pack is configured as 5x2 (5 series stages of two parallel pairs each) * Other cells are in near-new condition. * OEM Factory battery exact matches are rare and quite overpriced.  (1500mah x 15A discharge rate @ $10-20 shipped.) * Due to improvement in battery tech, I can get batteries that outperform OEM in every spec for 30-40% of what the OEM costs (2500mah x 20A discharge rate @ $4-6 shipped.) * The battery pack is always charged on a cell-balancing charger. Assumptions:  (Correct me if I'm wrong here, especially on the 2nd one) * The partner cell to the dead one is now suspect, due to being undercharged (down to <.1V)  by it's dead partner. * I should be able to just replace the bad cell and it's partner with the higher spec'd batteries and it shouldn't be a problem Is this workable, or will having non-identical cells for 2 of the 10 cells cause problems?  (I'm totally fine with the pack only being as strong as the weakest link, and only getting OEM performance out of the replaced cells.) I'd rather not have to replace all 10 cells, but I'd rather do that than replace 2, and -then- have to replace all 10 because the combination didn't work.

Topic by SvdSinner    |  last reply


Power supply from Ebay

I bought Switching power supply (220v AC>DC 0-48v DC 1000w 0-20Am)for my ZVS Driver, but not working properly, l need full 20Am, but this piece of shit do not given me more than 6.00Am at 50v! And values on the display are arbitrary!? I wrote on the seller for this problem, he wrote to me "When used load equipment The special insert must be taken out " I kill myself from 2 days to find this special insert, can't find it! Someone can tell me where to find this special insert? I post the full imal from the seller, he explains for knowing people, l need someone to explain to me with semple words / Dear friends The supplier replied that if you want to reach 20A, it depends on the actual current of the load. If the load is 6A, the maximum current can only be 6A. The actual current is determined by the load, and the actual current value is displayed. How to limit current: If no current is required when the current is limited, it is necessary to connect a plug to display the current value. The 6th and 7th connection port can be connected to a special plug to limit the current (regulate current). When using load equipment, The special insert must be taken out. When the load equipment is connected, the current value can be adjusted directly in real time. The maximum digital display current value is the maximum current value of the load equipment. Digital display current value will not have continuous real-time synchronous digital display, only the maximum current value of the device will be displayed./

Question by Viktor Karadzhov    |  last reply


How to make a circuit board?

I have bought an assortment of resistors and capacitors and circuit board s, but how to make Circuit board I need to make a circuit board for a project. It is all 12vdc, I have a 1a fan and a 6a thermoelectric device one setting 1, plus another 6a on setting 2, and a 3rd on setting 3 So 1 is 7a 2 is 13a 3 is 19a How to make the board. . Also a second device has the 1a fan plus a 4watt element, plus another 4w on setting 2, plus another 4w on setting 3 So 1 is 1a and I think 0.4a= 1.4a 2 is 1.8a 3  is 2.2a. I think I need to know what components to use, Right now I have each portion wired directly to the switch which is directly wired to the battery. I have burned out one of the 4watt units (I assumed it would just draw the power it needed) so I don't want anything else to burn out. Eventually I wanted to have a rotary multiple switch controlling both sets with a neutral in the middle (if I can find it) Printing a circuit board is next to learn,  but I already bought several boards and various assortment of components, just don't know which ones to use Also where to buy this.       12vdc 20a 7 position off in center rotary multiple switch for sale

Question by Johnieahenderson    |  last reply


How can i keep my MOT from drawing to many amps and why dose it heat up so much when I draw arcs?

I just made a 3 phase MOT power supply and it's fun to play with (while being safe) but every time I use both phases it trips the breaker after only 2 arcs, sometimes it trips just from plugin it in, I am using a PFC cap on the mains side as well as a long extension cord, I have one of the transformers ballasted, and one of them has 3 MOC's in series on its output, the breaker can handle one of them just fine...for a little while. Is there any thing else I can do besides buying a bigger breaker switch? I'd say mine is 20A but i dont know for sure.  Every time I draw arcs from my MOT it heats up really fast really hot, I am using the same setup as above , the only thing I can think of is to submerge it in oil but I dont want to do that because I'll want to make changes to it. What makes it different from a welding transformer in that they are made to draw arcs from but when you draw an arc from a MOT its a direct short and will eventually destroy the transformer?

Question by Jimmy Proton    |  last reply


Controlling ws2815 from raspberry-need a little technical help

Hey guys! Im pretty new to this stuff. As part of an ambilight “project” im trying to use ws2815B with a raspberry pi3b+ I use a 12V 20A (meanwell) psu for the leds and an raspberry 5.1V 2A adapter(bought it because new rpi hated everything else!). So powering seems sufficient. 12V is stable. I already managed to get the lights working somewhat. Even video capture works “fine”, so the lights are okish and delay isnt “that bad”. However i managed to fry the gpio18 on the pi... I dont know what caused it for sure - but i found a broken 12V cable to the strip. Maybe that...or... My new rpi also keeps hanging a LOT when the leds are attached. I can still push buttons and try to restart with ctrlaltdel(which sometimes works sometimes doesnt) but completely hung(instantly loses network connection and only ctrlaltdel does anything), although colors still work on the strip as the video capture captures different image. So hyperion is running. First few leds are off or look like dead pixels. The Rest shows the right colors. Can this hanging and erratic behaviour be because of different logic levels? If so which logic level converter should i be using? Ws2815 is 12V but it works as mentioned above with 3.3v logic from rpi with some errors. If i bring it to 5v will it be enough? Or 12V logic level is needed? If logic level is not the issue, then what else? Thanks a lot for any input :)

Question by ferenc.lippai    |  last reply


How to choose wire gauge for Brushless DC motor?

I'm planning to build a Brushless DC motor, with inrunner perm mag rotor and stator on the outside. How can i determine the proper copper wire gauge for the stator windings? How much current will the motor pull? At first i thought it was just "Power = Voltage * current", so knowing the power and the voltage i should be able to figure the current. However, when the motor is spinning it generates back EMF, which counters the applied voltage and diminishes the current. At no load, the motor should draw no current for an ideal motor, and only a small current in real life to overcome friction and losses. In any case it would be much lower than the nominal current. So, for instance, a 1000w motor at 50v should draw 20A nominal, but in most situations it would be less than that? How much is the starting current, when you have to overcome inertia/tire friction? I know the motor can take higher currents for small amounts of time, before it gets too hot,but how can i determine what will be the "average" current. Is there a rule of thumb that motor designers use?  Also, the amp rating for each AWG seems to vary a lot. Some places list a conservative rating that is used for home wiring. But other places list much higher currents. If the stator is on the outer side and exposed to air, how much current can the copper handle for each AWG? Any insight will be appreciated, thanks.

Question by SlickT    |  last reply


Need Opinions on Dubstep song im working on

 :D im trying to become a beast at making Dubstep, ive been asking my friends and family on facebook and i think there telling me what i want to hear (and i am annoying some of them lol) ... so thats why i am making this so i can get a non bis opinion on the work i have done so far. plz feel free to "tell me how it is" cause i really want to improve what i do, you wont be hurting me lol you will be helping me improve my skill. (links will open a new tab to a cloud app, online storage so i can upload/ shear my work) http://f.cl.ly/items/0Z1K3e3Y303t3Z2w182w/NICK%20AW%20YEA.mp3 <- ill call this one aw yea, its a simple/ 14 sec song of me just trying to get ideas for what i want to build up to. foor some reason there is a part where the beat messes up (i think cause of rendering issues) but it sounds pretty BA  http://f.cl.ly/items/3b1H370C0g0N00171W19/piano%20fjnds%20I%20AM%20A%20BEAST.mp3 <- im going to call this piano intro, i wanted to make this a kinda darker one, i was even thinking about throwing a rap kinda lyrics to it, then near the end thats where im going to "drop the bass" and dub step it up. this is the kind of sound i am putting for the wub -> http://f.cl.ly/items/312K0j1p231d0l410i32/piano%20fjndswub.mp3 :D thanks to all that do post :D wub wub wub wub wub wub wub wub wub wub wub wub wub wub wub wub wub wub wub wub wub wub wub wub wub wub wub wub wub wub

Topic by Ares252    |  last reply


Choosing drive motors for kids riding toy

I'm building  "robot horse" for my daughter, and have the metal frame mostly complete.  The plan for locomotion is to mount reversible powered 6" wheels to the outside of each hoof, and steer tank-style. My biggest challenge is finding reasonably priced, reasonably powerful drive motors for each wheel.  My issues are  1)  I'm inexperienced at specing dc motors.       A) I'm not real sure how to translate published specs into real world motion.  I don't know exactly how much power it takes to get this reliably moving over rough ground to a top speed of around 1 mph.  I also don't have a good sense of much voltage you can pump into a DC motors.  (IOW, should I be able to push 2 x the rated voltage for a quarter second to get it moving? Will the motors naturally increase their amperage at a constant voltage (and thus power) as they are resisted by torque?)  How much power will starting from a stop take?  What about a slight uphill slope?     B)  I'm not sure what form-factor is best:  Gear motor?  Gear motor with final drive belt?  I would like to use worm-gear motors, as I think it would be safest if the wheels didn't move when unpowered. 2)  Hunting around supplier web-sites, I see lots of $20ish gear motors that use 5-20W of power.  Great price, but would 4 of them make enough power?  (See #1A above)  Also, I see lots of fractional HP motors for >$100 that would unquestionably be strong enough, but would cost more than the project justifies.  I found very little in between.  Are there motors and gear boxes that could power this at a reasonable price?   Relevant clarifications and details: 1)  The horse is about 40" high at it's withers (shoulder) 2)  Frame is made of 1/2" square tube steel. 3)  Normal rider + vehicle will be about 150 lbs.  However, unquestionably, larger kids (or multiple small kids) will at some point hop on it and try to ride it.  At 250 lbs. rider+vehicle weight it doesn't have to go fast, but shouldn't burn up the motors. 4)  It'll be powered by a lipo battery pack that shouldn't have any issues with 20A+ max currents and can be sized as needed for voltage. 5)  I'd like to keep the motors and gears <$200 total, if possible. 6)  "Rough ground" = flat grassy turf or reasonably smooth gravel. 7)  Motors need to be reversible. Can anyone lend some perspective on what type of motors to buy for this?  How much power/torque should I look for?  Any advantages/disadvantages of any particular gearing style for this application? I am assuming that motors on each wheel are the way to go, but if there are any other power transmission schemes that would work better, I'm all ears.

Topic by SvdSinner    |  last reply


How to limit welder current (heat)? Answered

Hi All, I admit to being electrically dumb, well one step above dumb, I'm a software engineer not electrical engineer, but I don't even know enough enough to be dangerous yet:) I'm going to be converting an ac welder to dc. It's a harbor freight 90 amp flux wire job, comes from the factory as AC for some unknown reason, but should be DCEN for FCAW welding. There are several walk throughs availabile online. I don't know the rules for linking to other forums, so I won't post a link, but you can google 90 amp welder dcen conversion if you want details. I attached an image of the circuit I got from a post by bluecatfish onweldingweb. I'll be taking the transformer output, running through a full bridge rectifier to convert to rippled DC, using capacitors to remove ripple, and lastly running through a torroid inductor. Another problem with this welder is it only comes with high/low power settings. The low is still too hot and burns through thinner metals.  I want a way limit current further, but maintain voltage for a stable arc. I'll be adding a bleeder resistor to drain the caps, which gave me an idea. At first I thought to use several more resistors in parallel with the bleeder to reduce current. I imagine this might work but be horribly inefficient. It would still use all available power from the supply, just converting some of it to heat, leaving less power for the arc. I've read that adding resistance in series will reduce current, but won't that drop voltage available for the arc? Then I was thinking, I have a motor speed control for a router. I believe this is a pwm. Could it be used to chop the mains input (120v 20a) to the transformer and reduce overall output without effecting voltage(I've read this is 38v 80a in the factory state before my mods)? since I'm adding capacitors downstream, will they just discharge too fast leaving me with ripple/pulsing? If so, how would I slow the discharge rate? (I'm looking at 3x or 4x caps 22,000uF @65v in parallel on a bus bar, so 66,000 or 88,000uF total). Sorry if in not making sense, as I said in the intro, I have a lot to learn, and right now, the more I read, the more confused I get. Edit:  After more research, and to hopefully use correct terminology, I think I'm talking about using a current divider when referring to multiple resistors in parallel to the welding leads. I think I'm referring to a switching regulator when I suggested using a pwm to chop the transformer input. Can either of these work like I'm hoping? Is there a better way, that is relatively simple?  Thanks in advance for your patience and help. 

Question by DonaldF9    |  last reply


Solar LED 2835 strip with rechargeable battery, controller and night sensor?

 Needing help with a solar set up to recharge and power a small led strip with 2835 LEDs. I need a small strip of bright LEDs to light up a address block during the night and it is in a rock column.  I want the set up to be as visually minimal as possible.  My plan is to have a solar panel charging a battery during the day, have the sensor turn the light on at dusk and off at dawn.  I have a reel of 2835 LEDs and I want to cut a 1 Ft length of them and mount below the address block to illuminate it.  I already have all the mounting details set and how I plan on running the wires.  I will put the battery, controller and dimmer in a box on the back of the column and close it off and run the wires through the mortar to the LED strip which will be sitting on a rock shelf.  The solar panel will be mounted on the top of the column which is almost totally flat.  My questions and assistance needed is on the design of the solar components, battery, controller, wiring, design and if it I have it all correct and it will work.  I have done hours of research on the net and think I have an understanding of this, but would like one you electronic wizards to proof my concept and provide any input on things I might need to add, change or improvements to make it better or more cost effective.  I also searched previous forum questions and didn't see anything exactly like this. Pic is attached on my general layout, but here is what I have come up with so far: -12v 10w Solar panel, $20 -Charge Controller, $6 -20a Fuse, $0 -12v 5ah battery, $16 -LED dimming controller, $6 -12v Photocell, $3 -2835 LED 1 foot strip (cut from reel), $0 --I can provide links and further details to the components if needed, but they are all standard items that you can get on ebay or amazon Total cost not including box housing is approx. $51   (seems like there should already be something like this available much cheaper, but I have searched a lot and can't find anything.  I don't want one of those bulky solar LED lights and I want something that will stay on for at least 8 hours at night) I did the research and 1 ft of the 2835 leds uses about 4 watts.  Looking at all the formulas I found and the battery I intend to buy, 5ah, I calculated it would run the LEDs for 14 hours.   4/12 = .34   * 1000 = 340    Battery is 5000mah so  5000 / 340 = 14.7 hrs Does this sound correct? Next was determining the solar panel required. I came up with the 10w panel to have enough to charge the battery.   10w / 12v = .83    battery again is 5ah, so 5 / .83 = roughly 6 hours Is this correct also? The other items are components to complete the circuit, protect the battery and controller and have the ability to dim the lights if they are too bright. I'm hoping I researched enough and did correct calculations and didn't miss anything. But please provide input, thoughts and anything I might have missed.

Question by Ti6    |  last reply


Can I power 3 small electronic components (video game, LCD screen, audio amp) with a 6 volt adaptor?

Hi, I need help working out the power supply issues on this project of mine. Once I have the parts defined I'm going to teach a DIY class to 5-10 young under-privileged kids where they can build their own arcade machine. I'm hoping to keep the costs down to under $50 as I will be self-funding this. I'm building a small desktop video arcade system using one of those old Namco Joystick boxes which are battery driven (4 AA batteries) and have an audio and video RCA jack which you hook up directly to a tv. There are 3 main components. Video Game/joystick box http://bit.ly/1lpVuXr Regarding the power requirements. All I know is that it takes 4 AA batteries. So 6 volts. I don't know how much current it draws. Can I use a multimeter to measure this? Do I need this information to move forward? 4 Inch LCD Video Screen http://amzn.to/1lUq0Kj Here is the range of power options for this device. Voltage/Current/Power 5.1v / .27a / 1.377w [lowest stable voltage] 6.0v / .25a / 1.5w 6.6v / .23a / 1.518w 7.4v / .20a / 1.48w 8.0v / .18a / 1.44w 8.6v / .17a / 1.462w 9.2v / .16a / 1.472w 9.8v / .15a / 1.47w 10.4v / .14a / 1.456w 11.0v / .13a / 1.43w 11.6v / .12a / 1.392w 12.0v / .12a / 1.44w [highest recommended voltage] Small Audio Amplifier board to drive a small speaker. Probably not more that 1 watt I'm guessing would be loud enough. Not sure what to use here. Any ideas? If this also can take 6 volts then everything can be powered by one 6 volt power supply. This looks interesting. https://www.sparkfun.com/products/11044 I would just have to add a speaker and a potentiometer for a volume control. It says it will take up to 5.5 volts. I wonder if I could push it and give it 6 volts or if not whether I could reduce the voltage slightly in order to keep everything at 6 volts. I've already built one of these desktop arcade machines ( http://www.jochumson.com/project7.html ) but ended up using both the video game batteries (which powered the video game) and a separate 12 volt power supply (which powered both the LCD and an audio amp board) and I didn't like that as you had to replace the batteries as well as have it plugged in all the time. I ended up using a small 3 watt amplifier which was WAY too powerful. I could only turn it up a little before the volume was earth shattering. And this was a small audio amplifier board.  I would prefer it to be as simply as possible. Just need to amplify the RCA audio output to levels appropriate to playing on a kitchen table. Not very loud. Ideally I would like to: Power all three things with the (4 AA batteries) that comes with the joystick. That would be ideal as it would allow this small video arcade machine to be portable. Assuming though that the batteries didn't drain way too fast. If the batteries don't provide enough current then the next best thing would be a power adaptor. Something like this assuming that it could power all three components (video game/joystick, video screen and audio amplifier).  http://amzn.to/1rza3bG So my issues are: Can I power all this with one power supply? And are there issues like voltage spiking that I have to worry about when connecting multiple components like this to one power supply? Or can I just hook them up in parallel assuming they all take 6 volts and the total current draw is less than the power adapter is rated? Any help you could give me would be greatly appreciated. Here's my first attempt from last year. http://www.jochumson.com/project7.html Thanks very much! Chris Jochumson

Topic by cjochumson    |  last reply


Printer disconnecting or USB port disappearing in Windows

First I thought to make an Instructable out of it but realised there are too many different printer models out there, so this time no images. What is this about you might wonder? Well, let me tell you my story first and you might see similarities to your problem. It all started with me getting a new PC as the old one got memory problems (RAM modules failed). After a few successful prints I noticed errors coming up in the log window. Mainly things like communication problems and that some data is sent again. Realised that on my new PC I did not check the speed settings for the COM ports, so I adjusted them to match the printer board and moved on without even bothering to check the logs. Then, half way through a bigger print, it all stopped and I could not even connect to the printer anymore. After a power cycle on the printer all was fine again but the error kept coming back every now and then. At this point I started to read up on the problem and the most common recommendation is to print over SD - too bad if your printer does not support it and too bad it does not address the issue at all! A few more technical answers pointed to the Logitech drivers, especially mouse, keyboard and 3D vision. As I was using the same outer hardware as before and also the same drivers (and same version numbers) I simply ruled this one out too, although it might be a vital clue for others. When starting to get frustrated and after opening a cold blonde I remembered that I had a similar issue a long time ago and that it was related to loose wires on the screw terminals for the power connection. Measured it all but according to my trusty multimeter all was fine. Now comes the fun part: I friend of mine with a HiFi fetisch was here when I testing the connection and he started laughing at my attempts. He explained that ALL his connections, no matter if power or audio signal are oversized! Here I started to wonder if he is up to something and looked up similar circuit board mounted power plugs. To my surprise they are all rated for anything between 1 and 5Amps. Even without a heated bed powered by the printer board I think everyone will agree that a max 5A connections is not enough. My frined then offered to check the plug and connector at his place - what a great thing to have friends :) He used a signal generator and small speaker with the plug as a connector between them. With an oscilloscope connected to both input and speaker you could see, while moving the plug, that the audio signal become somehow unclean - there where spikes and missing bits everywhere depending which way you wobble the plug. After taking the whole thing apart the destructive way we saw the cause: overheated contact areas with discolored surfaces. I replaced the plug now with a 250V/20A one from an old laser printer and had no USB or connection issues ever since. Ok, what's the thing with power and USB problems on a 3D printer? Almost all printer boards have the ground connections bridged to avoid interference on the USB signals. This mean, in case of a faulty power connection or one that is "dirty", the USB port on the computer can receive back EMF signal or even a voltage spike. In return a smart bios either disconnects the port or disables it until the problem is solved, in our case by restarting / reconnecting the printer. But even with no obvious signs of power problems you can get  a so called "dirty" connection. Dirty covers all from corrosion, worn springs for battery compartments, overheating or in the old days burnt relay contacts. For our printer it usually means that either the soldering connection on the board or a screw came loose, in rare cases like mine an undersized connector can burn out due to being unable to handle the currents. The bad thing is that you can not always spot these problems the easy way... Is there an easy way to tell that my USB problem is caused by a faulty power connection? Yes and no. Some boards offer indicating LED's, you connect power and the LED stays on even if the printer is disconnected from the PC. If it is more than just a Power on" indicator" this LED will be off after the printer stops working and in the device manager your serial port for the printer is gone. You might also hear the warning sound from Windows in regards to a device being disconnected. If all the above is true than most likely your power connection has a problem somewhere - if in doubt replace all screw and plug connectors for the power. Sometimes the problem is less obvious. Your print software might show communication problems in the log window or re-send a lot of commands. If the speed selection for the com port is the same as for the firmware of the printer board and as set in the printer software, it could also be a power connection problem. But to be on the save side try a shielded cable with ferrite cores on both ends first for the connection between computer and printer. Can I take any measures to prevent the problem? Sure, you could solder everything and make sure the wires are fixed in place so they won't move. But a simple indicator might be enough: Solder a piece of LED strip to the power connection on the circuit board - if the connection has trouble the LED's will show it in most cases by changing light levels or flickering. On top they act as a nice light to see what's happening during a print.

Topic by Downunder35m  


500W electric scooter control and instrumentation with Arduino mega

1. Introduction DC 500W motor control with an Arduino mega to limit starting current and to vary the speed of the scooter. The battery is in 24V, 10A.h. The following table summarizes their characteristics: https://i58.servimg.com/u/f58/17/56/35/17/a014.jpg https://i58.servimg.com/u/f58/17/56/35/17/a111.jpg 2. Bibliography: Link download : sketch_escooter_feed_back_reel_V1.ino https://drive.google.com/file/d/0B_fB3GAsM02FSlRTWHdyRkhuUW8/view?usp=sharing escooter_ampli_SIMULINK.mdl https://drive.google.com/file/d/0B_fB3GAsM02FOW9OdmlhdDhJZGc/view?usp=sharing escooter feed back ISIS.DSN https://drive.google.com/file/d/0B_fB3GAsM02FOXdRWFN5OWRMQkE/view?usp=sharing youtube  :  "study trotinette electric e-scooter 100W et 350W, wiring"  youtube https://www.youtube.com/watch?v=QqJ2-YiE8Tg&index;=75&list;=PLfZunVn_gcq7EOurXuWU2sRFmh6CbiUiL Article: «Study of electric scooters 100W and 500W (Arduino), Revue 3EI 2017» Pdf? Book «I realize my electric vehicle» at DUNOD 3. Open loop program To test the programming, we simulate the program in ISIS, as can be seen in the following figure. In addition, we have an LCD display to display data (duty cycle corresponding to the PWM at 32Khz, motor current, motor voltage, action on the pushbuttons, 4 push buttons are used. BP1 to manually increment the duty cycle, BP2 decrement it. BP3 set the duty cycle to 0, corresponding to the brake contact. The speed of the motor is practically proportional to the duty cycle https://i58.servimg.com/u/f58/17/56/35/17/a211.jpg We made our own current amplifier called a step-down chopper but it is possible to buy a shield There are many cards for Arduino to control DC motors especially of low powers and also of great powers as can be observed on the following links.http://www.robotpower.com/products/MegaMotoPlus_info.html http://www.robotshop.com/en/dc-motor-driver-2-15a.html https://www.pololu.com/file/0J51/vnh3sp30.pdf https://i58.servimg.com/u/f58/17/56/35/17/a310.jpg But all these chopper shields measure the current internally but there is no current limitation. In order to have a current limitation, an analog current loop is required using specialized AOP or IC or a fast digital current loop. But what should be the value of the limitation current? The choice of the current value is normally for the 1-hour operation service in order to be able to carry out relatively long climbs without reaching the critical temperature of the engine. In our case, the limitation current must be Limiting motor = Power / Upper battery = 500W / 24V = 20A In addition, the power transistor of the chopper can only support 50A in our case. But in open loop, it has no current regulation, so as not to exceed the maximum current, a ramp of the duty cycle will be used. A 0.1 second interruption routine will be used to measure the voltage of the current (sample measurement, sample). This sampling time is arbitrary but does not allow to be faster than the rise time of the current because the electric time constant of the motor is L / R = 1.5 ms. Open loop operation with a 25.5s (8bit) ramp and 0.1s interrupt routine provides a good understanding of the operation of a DC motor drive. The display will only be done every 0.2s to have a stability of the digits on the screen. In addition, a digital filtering will be done on the current and the voltage on 4 values therefore on 0.4s. [b] Algo open loop [/b] Interrupt Routine All 0.1S Read voltage and current Loop loop (push button scan) If BP1 = 1 then increment PWM If BP2 = 1 then decrement PWM If BP3 = 1 then PWM = 0 Displaying variables every 0.2s Code: [Select] // include the library code: #include #include #include #define SERIAL_PORT_LOG_ENABLE 1 #define Led     13       // 13 for the yellow led on the map #define BP1     30       // 30 BP1 #define BP2     31       // 31 BP2           #define BP3     32       // 32 BP3 #define LEDV    33       // 33 led #define LEDJ    34       // 34 led #define LEDR    35       // 35 led #define relay   36       // 36 relay #define PWM10    10      //11   timer2    LiquidCrystal lcd(27, 28, 25, 24, 23, 22); // RS=12, Enable=11, D4=5, D5=4, D6= 3, D7=2, BPpoussoir=26 // Configuring variables unsigned   int UmoteurF = 0;  // variable to store the value coming from the sensor unsigned   int Umoteur = 0; unsigned   int Umoteur2 = 0; unsigned   int Umoteur3 = 0; unsigned   int Umoteur4 = 0; unsigned   int ImoteurF = 0;  unsigned   int Imoteur = 0; unsigned   int Imoteur2 = 0; unsigned   int Imoteur3 = 0; unsigned   int Imoteur4 = 0;            byte Rcy=0 ;    // 8bit duty cycle unsigned    int temps; // the setup function runs once when you press reset or power the board void setup() {   pinMode(Led, OUTPUT);   // Arduino card   pinMode(LEDV, OUTPUT);   pinMode(LEDR, OUTPUT);   pinMode(LEDJ, OUTPUT);   pinMode (PWM10,OUTPUT);     // Pin (10) output timer2   //  digitalWrite(LEDV,LOW);   Timer1.initialize(100000);         // initialize timer1, and set a 0,1 second period =>  100 000   Timer1.attachInterrupt(callback);  // attaches callback() as a timer overflow interrupt   lcd.begin(20, 4);    Serial1.begin(9600);   TCCR2B = (TCCR2B & 0b11111000) | 0x01;         //pin 10  32khz    http://playground.arduino.cc/Main/TimerPWMCheatsheet                                                   //http://www.pobot.org/Modifier-la-frequence-d-un-PWM.html   //   analogWriteResolution(bits)      https://www.arduino.cc/en/Reference/AnalogWriteResolution lcd.setCursor(0,1); lcd.print("Rcy"); lcd.setCursor(10,1); lcd.print("Um"); lcd.setCursor(5,1); lcd.print("Im"); lcd.setCursor(10,1); lcd.print("Um"); lcd.setCursor(20,1); // 4 lines display * 20 characters lcd.print("BP1+"); lcd.setCursor(25,1); lcd.print("BP2-"); lcd.setCursor(29,1); lcd.print("BP3=0"); } // Interruptions  tous les 0.1s void callback()  { temps++; //toogle state ledv for check   if ( digitalRead(LEDV)== 1 ) {digitalWrite(LEDV,LOW);}     else {digitalWrite(LEDV,HIGH);}     analogWrite(PWM10,Rcy);   // frequency Umoteur=analogRead(A0); Imoteur=analogRead(A1); Imoteur2=Imoteur; Imoteur3=Imoteur2; Imoteur4=Imoteur3; ImoteurF=(Imoteur4+Imoteur3+Imoteur2+Imoteur)/4 ; Umoteur2=Umoteur; Umoteur3=Umoteur2; Umoteur4=Umoteur3; UmoteurF=(Umoteur4+Umoteur3+Umoteur2+Umoteur)/4 ;   }// End routine // Loop corresponding to main function void loop() {    // BP + LED   if ((digitalRead(BP1))==1) {     lcd.setCursor(20,0);      // Column line     lcd.print("BP1");     digitalWrite(LEDR, LOW);        digitalWrite(LEDJ, LOW);     Rcy++;                        // PWM incrementation     if ( Rcy>254)  {Rcy=254;}     delay(100);               //8bits * 100ms = 25S increment 25ssecond slope     }        if ((digitalRead(BP2))==1) {     lcd.setCursor(20,0);     lcd.print("BP2");             Rcy--;      if ( Rcy<2)  {Rcy=2;}  // PWM almost at 0, engine stop         delay(100);      digitalWrite(LEDR, HIGH);     digitalWrite(LEDJ, HIGH);     }   if ((digitalRead(BP3))==1) {     lcd.setCursor(20,0);     lcd.print("BP3");      Rcy=2;               // PWM almost at 0, engine stop     } if (temps>=2)  { lcd.setCursor(0,0); lcd.print("                "); // Erase line lcd.setCursor(0,0);     lcd.print(Rcy); lcd.setCursor(5,0); ImoteurF=(ImoteurF)/20;     //resistance (5/1024)*(10/0.25ohm) si ACS712 66mV/A                            // For resistance 1ohm (ImoteurF) / 20; Simulation 5/25 lcd.print(ImoteurF); lcd.setCursor(10,0); UmoteurF=UmoteurF*10/38;                              //10/38   10/30 simula if (Umoteur>ImoteurF){UmoteurF=UmoteurF-ImoteurF;  }  //U-R*I lcd.print(UmoteurF); temps=0; }// End if time    } // End loop https://i58.servimg.com/u/f58/17/56/35/17/dsc_0614.jpg Since there is a limit of 9000 characters in the forum below Open loop program feature previous The interrupt routine lasts only 250 microseconds, the loop of the main program which scans the action of push buttons is 13micros and the display time of all data is 11ms. Thus, it is possible to improve the sampling period and thus the speed of the regulation of the current. The Arduino makes it possible to make the instrumentation of the scooter so to know the power, the consumption in Ah and Wh, to measure the speed, to know the consumption according to Wh / km, to measure the temperature of the engine, Have a safe operation. But for now we will see how to limit the current 4. Closed loop program, limited current control The sampling period will increase to 0.01 seconds (interrupt routine) If the current is less than the desired value, then the duty cycle can be increased or decreased to the desired value which is the setpoint. On the other hand, if the motor current is greater than the limiting value, there is a rapid decrease in the duty cycle. So as not to exceed the value of the duty cycle if it is saturated to 254 maximum and to the minimum value 6. Code: [Select] if (Imoteur<4000)                    // No current limitation at (20A * 10) * 20 = 4000   {if (consigne>Rcy)   {Rcy=Rcy+1;}   // Pwm ramp + 1 * 0.01second pure integrator    if (consigne    if ( Rcy>254)  {Rcy=254;}           // Limitation of duty cycle    analogWrite(PWM10,Rcy);   // Frequency 32kHz timer2}         } if (Imoteur>4000)  { Rcy=Rcy-5;              // No current filtering, to be faster                     if ( Rcy<6)  {Rcy=5;}       // Rcy is not signed, nor the PWM therefore Rcy minimum must not be less than 6                   analogWrite(PWM10,Rcy);   // Frequency 32kHz timer2}                        } 5. Closed Loop Program, Limited Current Control with Acceleration Handle An acceleration handle provides a 0.8V voltage when not operated and a 4.5V voltage when the handle is fully engaged. Instead of using pushbuttons to increase or decrease the speed setpoint, an acceleration handle will be used Code: [Select] Upoignee=analogRead(A3); // The relation in Upoign and the setpoint which corresponds to the duty cycle corresponds to if (Upoignee>100) { consigne=(Upoignee/2);     //0=a*200+b    et 255=a*800+b                      consigne= consigne-100;                   }                            else { consigne=0;   }               if (Upoignee<100) { consigne=0;  }     // redundancy     6. Temperature and safety program of the motor with the current measurement The outdoor temperature measurement can be easily performed by the LM35 component which charges 0.01V by degrees Celsius Code: [Select] temperature=analogRead(A2); //lm35 0.01V/°C temperature=temperature/2;       // Temperature coefficient lcd.setCursor(5,2); lcd.print("      "); lcd.setCursor(5,2); lcd.print(temperature);   // Display in ° C lcd.setCursor(9,2);      // Erasing secu display lcd.print("     ");   if (temperature>80 ) {lcd.setCursor(9,2);         // If motor external temperature is above 80 ° C                      lcd.print("secuT");                       Rcy=0;} In addition, thermal safety by measuring the motor current will be added. If the limitation current is greater than 10s then the motor will no longer be powered for 30s. A "secu" display will appear on the LCD display. This safety makes it possible to cut the motor on slope too high and when blocking the engine but it would be necessary to add the measurement of the speed in the latter case Code: [Select] if (timesecurite>=10000 ) {flagarret=1;      // If limitation current for a current of more than 10s                               timerepos=0;                               consigne=0;                               Rcy=0;                                 timesecurite=0;}       //   Then stop engine during a downtime    if (flagarret==1 ) {lcd.setCursor(9,2);         // If limiting current for a current of more than 20s                      lcd.print("secU");  }     //   Then stopping the motor for a stop time and display                                                     if (timerepos>=30000 &&  flagarret==1) {flagarret=0;                                           lcd.setCursor(9,2);      // After a rest time here of 30s                                            lcd.print("       ");   }   The display can be observed if the temperature is above 80 ° C https://i58.servimg.com/u/f58/17/56/35/17/a017.jpg Thermal safety by measuring the motor current (digital thermal relay) which allows to know the image of the internal temperature of the engine would be ideal. But for this, it is necessary to know well the thermal modeling of the motor. 7. Measurement of the energy capacity of the battery The energy capacity of a battery is in A.H, we will display the value in mA.H to have a high accuracy. The capacity will be in A.Second in the following equation. So to have in mA.H, it will be divided by capacity by3600. Capacity (A.s) n = I * Te + Cn-1 with Te = 0.01s and I multiplied by 10 So in the interrupt routine Code: [Select] capacity=ImoteurF+capacity ; And in the display Code: [Select] lcd.setCursor(0,3); // Display of energy capacity lcd.print("C mA.h="); capacity1=capacity/(18000);   //18000=3600*5  5=> Current measurement coefficient lcd.print(capacity1); To check a current of 10A with an adjustable resistor and after 30s, the capacity must be 83mA.H 8. Power and modeling with SIMULINK Modeling helps to understand the vehicle and its control. In addition, it is possible to compile the control part directly into the Arduino program from simulation under Simulink. But it will not be possible to simulate the instrumentation with the LCD display. In the following figure, we can observe the simulation of the programming of the chopper with the current limitation with Simulink. In the following figure, the green box shows the duty cycle control to vary the speed and the red border the current limitation. The controller of the control is here a simple integrator but it is possible to carry out a multitude of control. https://i58.servimg.com/u/f58/17/56/35/17/azub_c15.jpg In the previous figure, it can be observed that the current is well limited to 25A from 2s to 9.5s. Then, the current reaches 10.8A under established speed regime at 22.5km / h. The dynamics are similar to the tests carried out. With a slope of 5%, the cyclic ratio reaches only 100% as can be seen in the following figure. The speed will reach painfully 19km / h with a current of 24A and a motor power of 580W. See article: Study of electric scooters 100W and 500W (Arduino), 9. First conclusion It is easy to control a 500W DC motor with an Arduino and some components So repair many scooters that are in DC motors. But it takes some knowledge (automatic, engine) to know how to properly manage the engine and limit its current so as not to damage it The display of the speed, the distance, the operating time to know the Watt.km / km can also be realized with a menu 2. The .ino program as an attached file, But it is not possible to put an attached file in ISIS electronic labcenter? What is this forum? It would be desirable that the compiler could generate the.cof to debug in Isis and test the program line by line .... Arduino still has to make a lot of effort to be on the same level as other microcontrollers 10. speed measurement (tachometer) Velocity measurement is carried out using a hall effect sensor SS495 or A1324 which counts each revolution of the wheel. It is enough to enter the perimeter of the wheel of the scooter (130mm of radius therefore 0.816m in the case To have the speed, it is enough just to divide the number of turn of wheel on an arbitrary time of 1s to have a minimum speed of 0.81m / s therefore of 2.93 km / h. In addition, an average filter with 3 values will be used to display the speed. At 25km / h, there will be 8.5 laps. To count the turns, an external interrupt routine will be used on input INT0 21 of the mega card. http://www.locoduino.org/spip.php?article64 To simulate the speed, a pulse on input 21 will be used with a duty cycle of 10%. https://i58.servimg.com/u/f58/17/56/35/17/a018.jpg Code: [Select] void INT0b21() {   Tspeed++;   // External interruption to count the number of turns } // In the set up declare the interrupt routine when the 5V edge of the magnet detection is done   attachInterrupt(digitalPinToInterrupt(21), INT0b21, RISING );  // External interruption // In loop if (temps09>=5)  {        // 1 second loop lcd.setCursor(13,2);      // Erasing speed lcd.print("kph     "); lcd.setCursor(16,2); speed1=Tspeed*2937;      //1tour*816*3.6/1s=2.937km/h speed2=speed1;           //Tspeed (rate/seconde) speed3=speed2; speedF=(speed1+speed2+speed3)/3000;   // To put in kph lcd.print(speedF,1);    // Display to the nearest tenth Tspeed=0;   // Reset counter temps09=0;  //reset time } To improve the accuracy of the velocity measurement, it is possible that the sampling time of the velocity measurement is dependent on the velocity. For example: For speeds less than 10km / h sample at 1second, but above 10km / h sample at 2 seconds. 11. Distance measurement for autonomy The distance corresponds to the total number of turns of the wheel multiplied by the perimeter of the wheel. So do not set the number of turns to 0 for each sample. On the other hand, the reset of the distance will be done when pressing the reset of the Arduino Mega. The distance display will be displayed to the nearest second. At 32km / h, it will take 2 minutes to do 1km as can be seen in the following figure: https://i58.servimg.com/u/f58/17/56/35/17/a019.jpg Code: [Select] void INT0b21() {   Tspeed++;   // External interruption to count speed   nbrRate++; } lcd.setCursor(13,4);      lcd.print("km      ");  // distance=(nbrRate*816)/1000;  //distance m distance=distance/1000;  //distance km lcd.setCursor(15,4);      lcd.print(distance,1);  You can observe the electrical installation with the chopper, the arduino, and the display when the program is set up https://i58.servimg.com/u/f58/17/56/35/17/dsc_0613.jpg 12. Synthesis The RAM space is used only at 4% and ROM space at 3%, for an Arduino mega. So we could take an arduino a little smaller. But, there are 8 Lipo cells to make the 24V power supply to power the engine via the chopper. Therefore, the voltage measurement of each element will be on the Arduino with a JST connector. This measurement makes it possible to know if a cell with an internal resistance which begins to pose a problem and to know if the balancing of each cell has indeed been carried out. It is possible to switch to 36V with 12 cells also with the arduino mega without using an external shield that multiplex 24 analog inputs on input A0 It is possible to send all data to a smartphone via Bluetooth HC06 via pins 20, 21, RX1 and TX1. But the application under android realized under JAVA Studio can not be shared on this forum. This part will not be explained. After having made the instrumentation of this scooter, a study should be carried out on the precision of the measurements, it is possible to read "Instrumentation of a low-power electrical motor vehicle" eco marathon "type Revue 3EI N ° 81, July 2015 http://www.fichier-pdf.fr/2015/09/07/instrumentation-vehicule-faible-consommation-eco-marathon/

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