had no idea this existed pretty trippy. i found this by texting the word white on my phone and accidentally typed whike, and i noticed my phone didnt put a red line under it, so i thought it must be a real word then and here i am. sail bike what a cool idea. thanks for this.
Well, that's an interesting way to have found a Whike. I still own it, and it's great fun, although I don't use it much. I usually have the opposite problem trying to find others with them as searches tend to autocorrect to white when I want it to find Whike.
Hello, unfortunately I can't help with that as they didn't have any information with them. I got them from Ebay years ago from a seller who had obviously bought in bulk and repackaged. Sorry about this.
Hi, i'm from Brazil and i appreciate your videos of hx711. I'm study them to my engineering in electronics. i would like to know which model of hx711 are you using (i mean which factory batch of hx711 are you using), because my hx711 doesn't work with crystal osscilator 20MHz (model HC49) when i put the rate pin to high level (5V) the hx711 return to me 70~80Hz like he is using his internal osscilator itself. The hx711 only work with the 20MHz crystal when i put the rate pin in low level (0V) and i receive 18 sample rate data as well the datasheet informed. I suppose two things: .the 20MHz crystal oscillator it's not exactly 20MHz, that can be a little bit more like 20,102MHz (example) .the 20MHz crystal oscillator it's exactly 20MHz indeed, but the hx711 doesn't support this frequency of 20MHz. Despite the time when this video was released, i hope and wait with your help/answers. PS: the model (factory batch) of hx711 i already used is hx711 7916042F.
@RAFAELFERRARILOBATOGOMES Hi, glad you have found them helpful. I have just checked mine and the factory batch number is 712405204F. My guess is you are correct and the crystal is either above the maximum frequency or the HX711 simply can't handle 20MHz. I've never tested one with a 20MHz crystal.
@@Ed.R These days after send the message, i tested the hx711 that i was using with a 16Mhz crystal oscillator (model HC49S) and put the rate pin in low level, it is supposed to be working because 20Mhz crystal was working, but the 16Mhz doesn't work anyway, weird thing... so, i concluded the problem is not frequency and it is the hx711 itself. would you have availability to test a 20Mhz crystal on your hx711 and see if it is working? i researched for the same number of factory batch on aliexpress and shopee, but i can't find. if you have the link to buy, i will appreciate.
As I explained in the video the tiny crystals I was intending to use with a GND connection didn't work. Only the 2 pin crystals worked. Wondering if its something similar but perhaps the opposite way around. I can't help with the source of the chips as I had them provided by JLCPCB. They soldered them for me.
I've only used Arduino Nanos or Nano Everys for the power meters I've made so far. Have been wanting to upgrade to a Nano-33-ble so I can use Bluetooth or ANT+. Never considered an ESP32 but I do own one.
hi, really love your work on this sensor. how did you connect your wires from the sensor to the HX711 breakout board? I can tell that you put V_cc as E+ and GND as E-, but for your B- and B+ is it V1 and V2? Thanks!
Thanks, it's been a while so a little rusty on this now. The data sheet I'm looking at says V+ and V- but I'm guessing V1 and V2 are similar. You are correct with the other 2 V_cc and GND. As long as the voltage output is low and within the range of the HX711 it should be fine. Just flap the wires at B+ and B- if the reading goes the wrong way.
I am really thinking about getting the N380 version for a hardtail MTB, as nowadays you can buy them for around £200 on eBay. I am just hesitant about how badly I would feel the drag due to lower efficiency compared to derailleur. And the extra weight. But I am so fed up with finicky derailleurs, that always need cleaning and maintenance, and only shift properly for a short period of time.
If you are concerned about drag, I would go for one of the newer models like the Heavy Duty and Extreme. I know they are more expensive, but from my experience, the drag is below a level where it's noticeable, unlike with the older N360s and N380s.
My only concern is the way it is hitched to your bike. That high up on your seat post, if you snag something with the front of the trailer, I'm afraid it could snatch your bike right out from under you. Flipping you back against the trailer, in the process. Nice craftsmanship on the rest of the trailer, though. I'm just concerned about the hitch arrangement. I also like the electrical connection. Nice pilfery puzzler.
Thanks for your comment. I agree it's not ideal but I hate the bent tow bars. Difficult to make strong enough and always interfere with turning in one direction. The main issue isn't crashing as that's not good with any trailer and would throw you over the handle bars. It's the difficulty keeping the front wheel on the ground on steep hills and keeping balanced turning uphill. Any lumps or bumps under one wheel tends to pull the bike sideways but you get used to it.
I have also implemented something similar for a home trainer (by the way, thank you for the code, I adapted some of it). While analyzing the data I saw that, at least on the trainer that has flat pedals and an upright position, I get a lot (well, non negligible) of negative force on the raising part of the pedaling stroke. So, I guess, this translates to inefficiency in the pedaling action because the other leg has to push harder to raise the other. On a long ride this will matter. I am curious, since you have (or had) those real power meter pedals, does the Garmin software show something related to this efficiency and advice on improving it?
I noticed that negative torque to and obviously it does reduce the average positive torque. However I see it as simply the downwards leg lifting the upwards leg. Balanced and not really adding extra effort. I'd have to think about it to decide if its what I would call an inefficiency although obviously if you learnt to lift that leg it would increase the potential power. I personally find other factors to be a greater limit to my power output. The Garmin pedals are an older model so don't have that feature. I went for dual sided as I wanted my left/ right balance which they do give.
Very nice work! I'm also trying to put together a power meter for a fitness bike. To be fair, I was planning on using your code for calculating the power, but unfortunately it is no longer accessible. Could you please share it again? Thank you!
Thanks and sorry about the link. The Arduino project hub just doesn't keep the project public. I created a Github page instead. I'll try and post a link in another comment if not I'll also update the video description. Just be aware the code will need modifications to make it work for you like timing and cadence calibration.
@@Ed.R Sorry, i missed the comment where you already shared the github link. I've been watching and rewatching the videos related to the power meter and some others. I have to say I admire your perseverance and ingenuity. Thank you for the code and the heads up. Also, thank you for putting up these videos.
@MrNoblody No problem I should have updated the video description months ago. I do tend to stick with things beyond when most people give up. That's all it really takes to get good at something. Good luck with the project. Don't underestimate that aspects of it will be a challenge.
@@Ed.R It sure took a lot of effort even though, having a working model made it far more easier. My approach is to iterate on an idea. I have started about a month ago with an arduino and some scale sensors from a broken one. Yesterday I have put together a working model with strain gauges and an ESP32 (that screams overkill :)) ) on a fitness bike.
Hi man. Thx for this tut, helped me out. Although your code got me frustrated for a moment. It doesn't show the correct sample time so I changed it + some extra comments in the serial monitor. I hope this displays ok in the comments: if (counter == 10) { // average over 10 samples can be changed for high or low sample rates but change value 3 lines below counter = 0; sampleTime = millis() - previousMillis; sampleTime = sampleTime / 10; // 10 should be the same as in the "if (counter == 10)" previousMillis = millis(); samplePerSec = 1000.0 / sampleTime; Changed this to 1000msec because the sampletime is correct now. Serial.print ("ST: "); Serial.print(sampleTime); Serial.print (",SPS: "); Serial.print(samplePerSec); Serial.print (", Value: "); Serial.println(reading); digitalWrite(RATE, rate); } I wish I had found out about the slow sample rate before I got these things to make Sim racing pedals. Just for fun, lets say I'm playing an F1 game and going 360 km/h. That's 100m/sec. At a sample rate of 80hz that's 1.1M resolution for a braking point. I'm not sure that's accurate enough. I'll see when the pedals are finished. At least I got it up to 80hz for the moment. See if I can find some 10mhz crystals. Or I have an arduino due that could replicate it to test it out. Thx again!
Great work, Ed. I'm thinking about starting my own power meter project and I'm drawing a lot of inspiration from your videos. Dual sided pedal power meters are still $1000 here in the US.
I don't, but the code is in the description. Just copy and paste into an IDE. Only bit missing is a greater than as RU-vid wouldn't allow it in the description. Try and compile and the IDE will find it, it's near the end of the code.
Hello, thank you so much for your video. I’m using the hx711 and inputting 5v from my arduino, but when I measure the E+ voltage output, it gives 0.4 ish volts, which is really low. I thought it might be the board, but I swapped it and it did the same thing. I’m using the chip with a half Wheatstone bridge and 2 strain gauges. I ended up hooking up the Wheatstone bridge to a 9V battery instead of connecting it to the E+ and E-. When it was connected to the E+ and E- and I tried calibrating to get a load cell output, it would give nan, or 0. After connecting it to the 9v battery, the load cell output gave me a reading but it was fluctuating a lot and did not give any consistent values. How can I fix this issue with the E+ and E-, and do u think that hooking it up to a 9V battery was ok to do? Do you think that is what’s contributing to the fluctuations?
Good work. I'm working on a project myself using HX711 and need to increase the sample rate. I'm interested in either purchasing your board or just sharing your schematic to build myself.
Thanks glad someone thinks so. I think most people dismiss the idea of automatic shifting when they think of derailleur gears shifting randomly on their own. Have tried automatic but not had it setup to their preference so find it annoying. Also can't tolerate the extra weight and inefficiency of a CVT. It's a shame because it's brilliant for commuting and training rides.
Hi Ed, if I have a premade board with pads "rate". It does not matter if I brisge those or not, rate remains 10hz, pin 15 is low. Would you, as a HX711 expert, know what I am doing wrong? Its a Jopto CJMCU-711. I would be so happy if you xould help?
Looking at the photos on the listing on Amazon it seems the jumper is already connected. Connected to ground so low. To get a high sample rate, you will need to remove solder and run a knife a few times between the solder pads. Hope this helps.
It's part of a series of videos on my channel. There are others which explain the bike it is from. However you are right it wouldn't have done any harm to have added a brief explanation at the beginning. An improvement to make next time.
They aren't as I gave up on the project. Have a half finished video edit about them. I felt I was just getting questions about how do I solve my unstable data problems and not really any interest in the features on my board. My board isn't a miracle cure and does, unfortunately, have a few mistakes. Basically, I'm worried about opening up a can of worms with people with limited electronics knowledge buying them and then expecting me to troubleshoot their project for them.
Thank you for sharing this information. I'm working on a esp32 BLE power meter which is compatible with Garmin devices. I'm unable to find your code on arduino project hub. can you upload it again?
Sorry about that I discovered the project which was public had been taken down and made a draft. I thought I had successfully submitted it for publication again a few months back but it appears it hasn't been. I can't seem to do it now, something missing, so will get back to you if I sort it. Otherwise maybe need to look at another site for sharing it.
Gotta be careful up there, you go from protected inlet or cove to the full potential of the Atlantic in a pull o the oars, reversing that one pull can take a bit effort…
Not sure If I missed something. Is there any issue using the onboard oscillator for sampling with the rate pin grounded for slow sampling or pulled high for faster sampling?
Glad you're playing with NRF52 chip. I think I've mentioned before, but I started out with an NRF51. Was a dud so didn't get very far. But it's a great chip family. I think you can also get better battery performance than the others (with some effort). Quite interesting that it is cheaper than the other options, because it is a (the) superior chip. Maybe it has to do with user-friendliness of the particular module. Another interesting thing you mentioned was the rarity of charging boards for 2 cells. Probably because all those cheap e-bay led rechargeable lights also usually use single cells. Good move using what you could find. Looking forward to version 4/5 with the full custom PCB ;) (if you go with an NRF chip, I have some reference designs, not my own, that would probably be helpful). Thanks for sharing. Great work as always. Keep it up!
Thanks for sticking with me and my irregular updates. Life has been busy and power meter development is low on priorities. The only thing holding me back from using an nRF52 is writing the code. The complexity of the code in Segger is beyond my current level of understanding. Also the motivation to switch is lacking due to the only benefit being the ability to pick up the data on a cycle computer, battery life and obviously the learning experience. If I upgrade the power meter I also have to do the same for the auto shifter. So a lot of code to rewrite. Having said this it would be great way to finish both projects so will continue working towards it even if it takes the next decade.
Hey! I'm currently into building my own powermeter. Have you ever faced problems with temperature compensation? I installed the strain gages and read some date from the sparkfun HX711, unfortunately the date wasn't stable and the numbers started to drift. Do you think this is a problem with my straingage installation/HX711 or in general a problem of temperatur compensation of the circuit(even if the wheatstone brigde should compensate the temperature)
I have definitely faced temperature related drift. It is very much a problem that is faced by power metres that use strain gauges. The cheap and easy way to deal with it is to simply zero the power meter frequency when there is a temp change. As was common years ago with early power meters. The layout of the wheatstone bridge can definitely minimise the issue. However, to really deal with it, the only option is to measure temperature and apply compensation. This is one of the reasons power meters are expensive.
@@Ed.R yeah, if the drift would be linear, I think it would be possible to integrate a temperature function in the code but unfortunately in my case it's a curve that flattens out.
There is nothing really special about the design. It just has the issues discussed in previous videos fixed and more ability to customise it. I would make sure the board you have is working as it should be. Also remember strain gauges are just difficult to work with, noise and drift are to be expected.
@@Ed.R yes, I have increased the voltage over 5v but no difference in noise. Also the pin from the left side it is connected to GND. So I don't really know what can I do to get rid of that noise. It should come from the electrical side. I noticed that running if from a battery instead of the usb or switching power supplies helps. Also it seems to drift over time. I also understood that the clock of the arduino might be to fast... Anyway thanks, let me know if you have any updates
@vasipro If you are a strong rider, which I reckon you are if you do that milage, then you will be lucky to get half that out of a hub. They are working on improving this and I'm currently testing an EXTREME hub.
@@Ed.R WoW 😳 I made 12570 Kilometers until now and the Gates CDX belt failed on me recently. The teeth started separating from the belt. 🤦🏻 The hub is still working. The total load of the bike is around 150 Kilograms out of 170 maximum allowed. I don't have money for Rohloff. Is Shimano Nexus/Alfine better than Enviolo Trekking Hub? Thank you in advance!
@Ed.R Hi, was wondering what you think about the seeeduino Xiao BLE NRF52840 sense board. it is very small, has the NRF52840 for comunication, has a built in imu which you can use to calculate the cadence, has a built in lipo charing option. has also a built in temperature sensor which maybe can be used to compansate over temperature changes, althohg for this we would probably need to collect enough statistics side by side with a formal power meter. seems like all you need to add is the adc and you should be good to go. i am now working on this board for a power meter using the ADS1220. would like to get your thoughts on it. Thanks!
@@shabso I think it appears to be a perfect board for homemade power meters. The only issue I personally have with it and why I'm not using one is writing the code for it. I just need to invest sufficient time into learning how to code properly rather than relying on the Arduino IDE.
