Were selling off the extras for anyone thats interested. Price Match lets you match the price of any item sold and shipped by RobotShop with a competitor's price! Can adjustable constant current/voltage source be made with Arduino? Ratio is multiplied with voltage at Rbottom for actual voltage value. Vout = (R2/(R1+R2))*Vin; I have not use your particular ESP8266 board, but it may be that 3.3V is the maximum voltage you can apply to the A0 input without causing damage. https://openenergymonitor.org/forum-archive/node/11011.html. lab electronics 24v dc 48v 5a step electronic using converter arduino ublox oled neo gps module My silicone mold got moldy, can I clean it or should I throw it away? As dBC pointed out, others might have been confused because one of your reasons appears to have gone against established practice. Check out our engineering forums, Getting started with MicroPython on ESP8266, How to use MicroPython with ESP8266 and ESP32 to connect to a WiFi network, Using MicroPython SSD1306 driver to interface an OLED display with ESP8266 & ESP32, How to use ESP8266s sleep modes in MicroPython, MicroPython: Time-related functions, timers & interrupts in ESP8266 and ESP32, MicroPython Reading analog signals in ESP8266 and ESP32, ESP8266/ESP32-based WiFi access point using MicroPython, How to achieve longer MCU battery life with low power sleep mode, Infineons CoolSiC devices support Deltas bi-directional inverter, Qualcomm and Mahindra to provide immersive in-vehicle experiences, Diodes launches high-efficiency synchronous boost converter, Help designing 1.6KW Isolated AC/DC with Constant Current Output, Help with Zero Crossing Detector with the 16F877A code on MPLAB XC8. I used ULN2003 relay driver to drive the relay coils. Four 12 volt batteries are connected in series to output 48 volts. I did not have much experience of analog multiplexers i can say any thing more abut them. Heres how people can take their projects from design to completion. Circuit may also be messy. arduino catalog How is making a down payment different from getting a smaller loan? First of all, I ended up caving in and doing a full blown 3d model blueprint of the robots entire skeletal structure to scale Hello @devvitltd and welcome to the RobotShop forum! So it would seem that "the Arduino's impedance varies while sampling, in such a way that the voltage divider's output will be affected. Digital pins can be reduced by using multiplexers. The best answers are voted up and rise to the top, Start here for a quick overview of the site, Detailed answers to any questions you might have, Discuss the workings and policies of this site, Learn more about Stack Overflow the company. 3) Draw an insignificant amount of current relative to the ratings of the solar panels. RobotShop, the World's Leading Robot Store For Personal and Professional Robot Technology. Was thinking something along the lines of a Raspberry Pi PICO and a bluetooth or WIFI module in each scale which is speaking to an RPI self hosting a wifi network / bluetooth host to receive the data and display it. Note that the proportions of both resistors define the voltage level for the analog in while the sum of both resistors are relevant for the current.

I selected one resistor Rbottom to be 10k ohm. Are you able to quantify the effect that lowering the driving impedance to a few tens of ohms had on your readings? I have tried creating a voltage divider with 2 resistors but with all values I have tried one resistor almost melts as soon as you connect to battery. How can we send radar to Venus and reflect it back on earth? Cool project! The trace below is the voltage at anADC input pin being driven to 0V through a 10K R. Immediately before initiating a conversion on this pin, I was doing a conversion on a different pin being driven to 5V, ensuring the cap was fully charged. Maybe the board you have has different built in scaling. I am also going to add some margin above the 65V max that the solar panel can output (plus it makes the math easier). How can we determine if there is actual encryption and what type of encryption on messaging apps? Analog multiplexers can also be used instead of relays. Have a technical question about an article or other engineering questions? By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. A1) Thats actually quite a long runtime for a skid steer robot. The problem with optocouplers is its hard to configure them and they require more effort than voltage divider. Nodemcu Arduino ide is used to write, compile and download the code in nodemcu WiFi module. So lets go through the calculations to select good resistor values. In voltage divider circuit two resistors are connected in series and source (battery) voltage is applied across its ends. Stack Exchange network consists of 181 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. Microcontroller can not measure 12 volts directly. Similarly if battery-3 is at 23v. Now its a hard task to accomplish. 2020 RobotShop inc. All Rights Reserved.Putting robotics at your service is a trademark of RobotShop inc. Hi @smurphy0620 welcome to the RobotShop Community. So higher is better but unfortunately you also need 2) that resistance to be low compared to the input impedance of the analog input. Most importantly, we would like to measure the balance of current in the three major branches of an off grid system: the Solar (always positive), the Load (always negative), and the Battery (+/- depending on the other two). I tested a few ESP8266 dev boards I had and to get 1024 on the Analog pin it only requires 3v on all my boards, specs do say 3.3 but all voltages higher than 3 just = 1024 so I will factor this in to my calculations, thank you again! Didn'tto repeat incorrect information, we were justexplaining our design process to the best of our abilities. RobotShop is also a leading force in Robotics Education & Research. UL2003 input is connected to multiplexer output. An extra power some time is also needed to power the optocoupler. We have an off grid 48V system here as well. Theres been several posts about this topic and weve used that knowledge to help point us in the right direction. So we can not measure individual battery voltage in this case. Hi @PeterJennings , I have tested the boards I have, they read max input (1024) at 3v (not 3.3 like the specs say) so I'll adjust accordingly, thanks. The question now is how the 3.33 volts is converted to 12 volt by nodemcu or how from 3.33 volts we can predict that at the battery side the voltage is 12 volts. We are able to scalethe values we are working with: the 23v possible range of our battery state of chargehappens in the upper 35%of what would otherwise be a 0-65v measurement. The technique is to measure the voltage across high potential battery first, than against the lower ones and negating the subsequent batteries voltage from the one at higherpotential. Ultimately, we ended up designing a custom PCB for the voltage monitor and sent the files off to OSH Park to have them printed. Why does connecting them to either0v or Vcc have the same effect? but with all values I have tried one resistor almost melts as soon as you connect to battery. Almost all of the current will be going from your source, through the resistors (R1 & R2) to ground. Its obvious from the above discussion that the voltage across Rbottom will not exceed 5 volts now. Note: Most ESP8266 development boards come with an internal voltage divider. Asking for help, clarification, or responding to other answers. As long as that limitation is understood and is acceptable, and it is being used at low voltages only, that is probably OK. Since most of the OpenEnergyMonitor ecosystem is geared towards grid-tied AC systems, weve spent the past few weeks working on new functionality that will allow us to monitor and log the power and energy readings from our off-grid setup. dk%vGCNm%BUvvt-8 SS2dx0!| )RG%Iy2- 09q ;M)d=zcz GEqXbtA|GX].xz=eB}y(Vgv'x)",(eY~t\^JM~?vd6&h_x:foU({l8!0w/wXVH)eaDg>g:-Wuw,1ale.ksI%kxm7X+3m/dBo="DqLx3#`l0#V!0s}g'sSA%]-T4t} Negating 48v-36v=12v gives us battery-1 voltage. In the above circuit four voltage divider circuits are used to measure voltage across each battery. For example, if you used resistors totaling , say, 1,000 ohms across a 50V supply then they would dissipate V^2/R watts = 2.5W. Thanks for the additional information and insight. I have a few ESP8266 devices, all analog pins can take up to 5v but I think in reality the A0 (ADC) should be max of 3.3v (see. If you are trying to reduce power consumption (and probably even if you're not) remember to disable the digital input buffer on your analog input pins. Can anyone suggest a way of reading high DC voltage (40-65v) with and Arduino (really I'm using an ESP8266)? With an opamp we can focus on the 23 volts that really matter and increase our resolution. Consequently wires can melt down in seconds. When flying from Preclearance airports to the US, do airlines validate your visa before letting you talk to Preclearance agents? All with email notifications. Voltage is divided against the two resistors according to the resistor ohmic values. 2) Give a convenient scaling factor. So this method is feasible only when batteries in series combination are not greater than 4. Adjust the below calculations for an input voltage of 3.0V not 1V. If you have any more method in your mind please let me know about it. Input is 0-100 V (which covers the required 40-65V range). It only takes a minute to sign up. Math Proofs - why are they important and how are they useful? So battery-2 is supplying 13 volts in series string array. Awesome, The service is always exceptional, and the range of parts match the service!!!! Now if 18 volts are at battery side it will be divided across resistors, 5 volts drops at 10k resistor and remaining 13 volts drops at 26k resistor. The two resistors need to be in the ratio 64:1 in order to drop a 65V input to 1V. During charging battery voltage can increase to 18 volts. This ratio is utilized in code for predicting the actual source/battery voltage. I made a simple diy project with the same above logic. Since we're gonna have to get them remade anyway, we can incorporate those changes into the opampwhile we're at it. For example for the above circuit the measured voltage across battery-1 is 48v and battery-2 is 36v. In my book, "in excess" means a few percent greater than but below about 20% greater, "Well in excess" means greater than that. Since we had to make a minimum of 6 of them, we have 4 more available for sale (fully assembled)if anyone is interested. Edit: The OP tells me that they get a max analog reading at 3.0V not 3.3V. The first 1.5 ADC clocks (out of a total of 13 for a conversion) charge the sample-n-hold cap. Referring to the ESP8266 Community Forum the analog input imposes a 50nA load, but they also state that the maximum input voltage is only 1V (equivalent to 20 M ohm impedance). For the sake of argument, let us assume the following Site design / logo 2022 Stack Exchange Inc; user contributions licensed under CC BY-SA. We run a woodshop on solar power, but some parts of the shop (lighting, mini fridge, office computer) are still on the grid. In the above circuit four voltage divider circuits are used to measure voltage across each battery. I've clocked it at about 800uA per pin on a 5V 2560 whichpotentially dwarfsanythingsaved by going with a high resistor divider. I've built a circuit to measure DC Voltage with full galvanic isolation using the HCPL-7520, and an Isolated DC-DC Converter to supply power to the isolated side, only pencil diags thus far, so will post more details later once I have done formal schematics. This means an op-amp buffer is not needed. Note: For the above circuit the resistors values should be selected using the same formula given above. Solar panel, car, ups, generator and back up batteries normally are at 12 volts. Our PCB combines three basic circuits: a voltage divider, anopamp, and a power supply. Pros. I also made an internet of things project on battery voltage monitoring over WiFi. How to read high voltage (40-65v) from a Solar Battery bank, electronics.stackexchange.com/questions/42710/, Measurable and meaningful skill levels for developers, San Francisco? The higher the battery capacity, the longer it will run, but the more it wil Hi! A few days after sending off the board design for printing I came across some comments in another thread about tying down the unused opampsto reduce noise and power consumption. How ratio is calculated is below. First i short circuited the 2 batteries and it cost me much at the end i finally fixed the code and inserted some delays which increased the hardware efficiency. Let's simplify. For example, Free shipping on orders over USD $ 100.00 *, Data Communication and Human Input Devices, Defense, Security, Surveillance & Inspection, * Subject to approval and not available for products shipped by others sellers through the RobotShop Marketplace, My order was quickly processed and shipped.

Marketplace sellers offer different shipping options. From automation in big factories handling bread, dough, fish, meats and vegetables to the living room and universities where they still can grip everything you throw on them and still be squishy and safe to be around for students. (It happen with me) . Voltage range to be measured = 40 - 65V 47K Forum has moved to: https://community.openenergymonitor.org. That wasthe assumption we were operating on, based on comments in other forums about the need for an opampbetween a voltage divider and the analog input pin. For example two 12 volt batteries are connected in series to build up 24 volts. Let's simplify by initially calculating the resistance required if R1 & R2 were combined into a single resistor: I would go further and say double that because I never like operating a resistor right on its maximum power rating. However, if you are interested, a op-amp circuit can be built from a 741 IC (among others) and is configured like this: It sounds as if you have tried using far too small a value resistors. Take a look I will discuss circuit its pros and cons below the diagram. But what about if we want to measure an individual battery connected to a cluster of batteries in series or parallel combination. You need a voltage divider with resistors that have large values. We are using a combination of a voltage divider and an opamp to scale, offset, and isolate the battery voltage from the arduino. Nice project! My test above was just performed on a single part, and the ADCinternal series resistance can varyanywhere from 1K to 100K. !, Fast shipping, well packed, very good quality products., Pololu ACS724 Current Sensor Carrier (5A), SparkFun Current Sensor Breakout - ACS723 (Low Current), Pololu ACHS-7125 Current Sensor Carrier (50A), SeeedStudio Non-Invasive AC Current Sensor (15A Max), Pololu ACS724 Current Sensor Carrier (0-10A), Digital Voltmeter Ammeter 30V 10A Red and Blue, SeeedStudio Non-Invasive AC Current Sensor (5A Max), Grove 5A DC/AC Current Sensor (ACS70331), M5Stack COM.PROTO-MEAS Current & Voltage Module 13.2, LiPo ''Fuel Gauge'' Battery Charge Sensor, SeeedStudio Non-Invasive AC Current Sensor (10A Max), SeeedStudio Non-Invasive AC Current Sensor (60A Max), Sunfounder XL6009 DC-DC Adjustable Boost Module Voltmeter w/ Display, National Control Devices 1-Channel DC Current Monitor I2C Mini Module, Octopus Non-invasive AC current sensor TA17-03 Brick, SeeedStudio Non-Invasive AC Current Sensor (30A Max), Zio Qwiic Current & Voltage Sensor INA219, Hiwonder Voltage Display Module Compatible with Hiwonder Robot, ODESC V4.0 / ODESC V4.1 Optimizes High-Performance Brushless Motor High-Power Driver, My Advanced Realistic Humanoid Robot Project. I appreciate the op. Here you will find the best selection of Robot Vacuums and other Domestic Robots, Professional Robots, Robot Toys, Robot Kits, and Robot Parts for building your own robots. Other batteries voltages can be calculated with same method. Q1) Battery? Referring to standard resistor values, 360K and 5K6 in series will be very close to 64:1 (64.28:1). Connect and share knowledge within a single location that is structured and easy to search. A. These calculations will also be suitable for 1/2 Watt and 1 Watt resistors. That drops to 42.6mAafterenabling all pull-ups. We put our selected components into a PCB design program (Eagle) and after using their automatic routing option, spent a few hours cleaning up the design to make it look pretty. That said, any other thoughts about the design that could be improved or tweaked? RoboCup is the largest scientific annual event to advance A.I., robotics and automation in the world. 4 to 16 multiplexer is used to drive 2 ULN2003 drivers. What should we do with each of them? How to tell reviewers that I can't update my results. The resistor values and power supplies for our PCB are specifically designed for 48v battery banks. Absolutely. 468). By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. At 50 volts its capable of passing 15 Watts of power to our little PCB, which is more than enough for our board but low enough to protect the input traces from bursting into flames. We are using the standard EmonPi to monitor all incoming grid power though our main breaker box. Closest equivalent to the Chinese jocular use of (occupational disease): job creates habits that manifest inappropriately outside work. It would have been nice to actually go a little lower, but I couldnt find lower values at our required voltage rating on DigiKey. I just did a spot check on a random ATmega2560 I had handy. We can also offset these values so they better fit into the range of the Arduino's inputs. So their pins are also working on 5 volt TTL logic. In this case R1 could be made up of 2-3 resistors in series: The expected voltage range is 40-65v. So it boils down to picking a pair of resistors that I made a simple diy project with the same above logic. rev2022.7.29.42699. Anyone can build a robot with the right steps. Amplifier may also be needed at end to amplify the voltage output. Enter the competitor's price and the url where you found it and we will do our best to match this competitor's price. It's just that alot of the designs used around here do monitor signals with a source impedance of roughly 10K and with no op-amp between them and the ADC input, so if there were a problem with a 4.7K source impedance, people would rightly want to know more.

Your Vin is 60V and Vout is 3.3V , Assume R1 and R2 have same value, then calculate the values of R1 and R2 using above formula i.e. #about-the-solution-of-odrives-purchase-limit-esc-1 About the solution of Odrives purchase limit ESC So Im selling https://sequremall.com/products/odesc-v4-0-optimizes-high-performance-brushless-motor-high-power-driver-foc-bldc-based-on-odrive ODESC V4.0 / ODESC V4.1 Optimizes High-Performa Hello @Khurram and welcome to the RobotShop forum, You can find different options in the https://www.robotshop.com/en/io-adc-converters.html IO Expansion & ADCs / https://www.robotshop.com/en/i2c-serial.html I2C sections of the store.

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