author
19Instructables476,140Views76CommentsJoined November 2nd, 2008

Tell us about yourself!

Complete Your Profile

Achievements

10K+ Views Earned a bronze medal
Show 1 More »
  • qthurtle commented on qthurtle's instructable DIY ECG EKG Portable Heart Monitor 7 weeks ago
    DIY ECG EKG Portable Heart Monitor

    This should be satisfactory I think. There is very little noise in the signal from the ECG front end, so in principle this should be fine. My slight hesitation is the fact that noise may be generated through the ground lead of the oscilloscope if the oscilloscope is connected to the mains (rather than being a battery-powered electronic oscilloscope isolated from the earth).I get lots of noise as soon as I connect any sort of mains power supply or USB 5V supply (computer-based or wall-plug) to the unit, so this is why I have concerns about the connection to the oscilloscope - I don't think the noise is anything to do with ripple on the mains-based 5V supplies, it is more likely to be earth potential issues I think. That is why I always use batteries.It is really important to have good sk...

    see more »

    This should be satisfactory I think. There is very little noise in the signal from the ECG front end, so in principle this should be fine. My slight hesitation is the fact that noise may be generated through the ground lead of the oscilloscope if the oscilloscope is connected to the mains (rather than being a battery-powered electronic oscilloscope isolated from the earth).I get lots of noise as soon as I connect any sort of mains power supply or USB 5V supply (computer-based or wall-plug) to the unit, so this is why I have concerns about the connection to the oscilloscope - I don't think the noise is anything to do with ripple on the mains-based 5V supplies, it is more likely to be earth potential issues I think. That is why I always use batteries.It is really important to have good skin contact (I have just used some old electrodes where the skin gel had dried out - terrible noise, no hint of an ECG signal - until I put a few drops of water on the electrode pads and put them back on the skin).I was very disappointed when I first connected the ECG front end up; all I got was lots of noise. There is no substitute for properly connecting a real human up to the board, using screened leads and electrodes. I don't think anything else will produce a heart trace - holding crocodile clips on the skin with sticky tape (or similar) just will not do!Finally, I have to warn about connecting a person to the ECG front end and then connecting the ECG front end to a mains-based piece of equipment. You should not do this. Nasty things could happen to the subject in the unlikely event of an equipment failure, lightning strike or other random act.I hope this helps. Best wishes.

    Following on from my main answer. The trace in this image shows how little noise there is in the signal from the ECG front end. There is no signal processing to remove noise in the software used to generate the trace. Every data sample (around about 200 per second) is plotted on the trace, with no averaging or anything. (The image full size is 538px wide by 237px high)

    View Instructable »
  • qthurtle commented on qthurtle's instructable DIY ECG EKG Portable Heart Monitor 2 months ago
    DIY ECG EKG Portable Heart Monitor

    Thanks - me too. Just need 6 years at college!

    View Instructable »
  • qthurtle's instructable DIY ECG EKG Portable Heart Monitor 's weekly stats: 2 months ago
    • DIY ECG EKG Portable Heart Monitor
      11,192 views
      137 favorites
      34 comments
  • qthurtle commented on qthurtle's instructable DIY ECG EKG Portable Heart Monitor 2 months ago
    DIY ECG EKG Portable Heart Monitor

    Many thanks for your interest.Best wishes

    View Instructable »
  • qthurtle commented on qthurtle's instructable DIY ECG EKG Portable Heart Monitor 2 months ago
    DIY ECG EKG Portable Heart Monitor

    Nice - a really clear diagram. Many thanks.

    Thank you for your contribution. I'm not sure which source I got the positioning of the leads from, but I had difficulty finding an illustration to show the best location, so had suspicions that my positioning was not brilliant.I see a device called a "Holter Monitor" which I believe is a "2 lead" ECG monitor used for 24 hour monitoring. Presumably this would use the same positioning that I should use. I have attached a couple of images which seem to reflect what you say. I will adjust the Instructable to include some better information about the positioning. Thanks for your help.On your comment about the rapidity of the trace I included - unfortunately, I'm no longer very young (according to my pension documents), and I did take myself to hospital on that occasion -...

    see more »

    Thank you for your contribution. I'm not sure which source I got the positioning of the leads from, but I had difficulty finding an illustration to show the best location, so had suspicions that my positioning was not brilliant.I see a device called a "Holter Monitor" which I believe is a "2 lead" ECG monitor used for 24 hour monitoring. Presumably this would use the same positioning that I should use. I have attached a couple of images which seem to reflect what you say. I will adjust the Instructable to include some better information about the positioning. Thanks for your help.On your comment about the rapidity of the trace I included - unfortunately, I'm no longer very young (according to my pension documents), and I did take myself to hospital on that occasion - Atrial Flutter apparently. Different to the Atrial Fibrillation I am more used to! I don't think I am alone. The UK's wonderful National Health System is sorting me out at no charge!

    Sorry - source of the two diagrams:https://www.rch.org.au/rchcpg/hospital_clinical_gu...http://www.heart-health.ca/faq.aspx

    View Instructable »
  • qthurtle made the instructable DIY ECG EKG Portable Heart Monitor 2 months ago
    DIY ECG EKG Portable Heart Monitor

    Thanks for your interest. I have just taken my meter to the Audio leads I used and can not read any resistance on any of the scales. So mine have not got any attenuation built in. I would have thought that any resistance between the signal lead and Ground would reduce the perceived signal voltage for the operational amplifier on the input. The circuitry for the front-end is published by 100RandomTasks if that helps - see attachment.

    View Instructable »
  • qthurtle commented on qthurtle's instructable DIY ECG EKG Portable Heart Monitor 2 months ago
    DIY ECG EKG Portable Heart Monitor

    I'm pleased you found it interesting. It was pleasing for me, because it involved so many different types of task. Best wishes

    saabaus, you are right. The worry is about mains voltages accidentally finding their way through to the ECG due to a fault condition (very unlikely I know). However, the path via the electrodes is directly across the heart - and the electrodes purposely give a very low resistance. Imagine the effect of 230V on the heart, when the voltages we are reading are a few thousandths of a volt (mV)In any case, any mains equipment (even just being nearby) swamps out the signal we are interested in due to stray pick up of voltages.Many thanks for your interest.

    View Instructable »
  • qthurtle commented on qthurtle's instructable DIY ECG EKG Portable Heart Monitor 2 months ago
    DIY ECG EKG Portable Heart Monitor

    Muito obrigado por seu interesse. Algo semelhante deve ser feito comercialmente por um custo muito baixo.(Many thanks for your interest. Something similar should be able to be made commercially for a very small cost.)

    Many thanks. Appreciated.

    Yep. It happens for a few hours separated by weeks or months. I have my monitor ready to go!See the image - normal on top, irregular on the bottom.

    View Instructable »
  • qthurtle commented on qthurtle's instructable DIY ECG EKG Portable Heart Monitor 2 months ago
    DIY ECG EKG Portable Heart Monitor

    No and Yes. It is no substitute for a proper "12 Lead" ECG/EKG These give detailed information about the electrical signals circulating around the heart and are an excellent diagnostic tool for many heart-related issues..This project does monitor one electrical region of the heart, it has an accurate time-base, so enables accurate timings to be determined. For me, its main benefit is that it enabled me to get a trace of a very intermittent problem which 'proper' medical monitoring had failed to pick up.

    Many thanks for your comment - the project was great fun and useful!

    View Instructable »
  • Stripping a Myford ML10 Lathe (Speed 10) Headstock - Taper Roller Bearings

    I have no clue whether you are getting these replies, but I'm trying to help! Instructables comments system seems to be broken.Myford are still actively advertising the part you need (expensive).https://www.amazon.co.uk/gp/offer-listing/B00SYI2P...

    View Instructable »
  • Stripping a Myford ML10 Lathe (Speed 10) Headstock - Taper Roller Bearings

    I have written a long and detailed reply to this post, including photos and links, but I cannot now see it. I hope the new system has not lost it. I really dislike the recent 'improvements' to this site - I may well switch to YouTube when I want to help others in future.

    View Instructable »
  • Stripping a Myford ML10 Lathe (Speed 10) Headstock - Taper Roller Bearings

    Sorry, I thought you meant the 'backgear cluster', my mistake. You are after the "65T Backgear" (I think the gear on its own had Myford part number 73/1209, and the whole assembly with the gear and the little tooth+screw is Myford part number 70/1226). Unfortunately, Myford don't seem to have that gear available, although you might email them to check (they have the version for the Super 7, etc) orders@myford.co.uk Phone 01422 885766 (UK is +44 from abroad).If you want to do threads, you really do need the 65T backgear to be working. It should align with the backgear cluster (the two gear pair which are on the separate axle). It looks like your headstock has been assembled incorrectly, the 65T backgear and the backgear cluster should align perfectly, before the 65T backgear al...

    see more »

    Sorry, I thought you meant the 'backgear cluster', my mistake. You are after the "65T Backgear" (I think the gear on its own had Myford part number 73/1209, and the whole assembly with the gear and the little tooth+screw is Myford part number 70/1226). Unfortunately, Myford don't seem to have that gear available, although you might email them to check (they have the version for the Super 7, etc) orders@myford.co.uk Phone 01422 885766 (UK is +44 from abroad).If you want to do threads, you really do need the 65T backgear to be working. It should align with the backgear cluster (the two gear pair which are on the separate axle). It looks like your headstock has been assembled incorrectly, the 65T backgear and the backgear cluster should align perfectly, before the 65T backgear allen screw is tightened to fix the 65T backgear onto the spindle.I think your other problem will go away once you have the headstock properly assembled. I have attached a few photos which might help you see what it should look like.In your situation, I would disassemble the spindle, check to see if Myford have a 65T Backgear, then (if not) take the 65T backgear to a local engineering company, to see if they can help by welding, brazing, etc.Best of luck

    View Instructable »
  • Stripping a Myford ML10 Lathe (Speed 10) Headstock - Taper Roller Bearings

    I'm afraid that the only one I can see at the moment is a full-priced one from Myford (£52.80)https://www.ebay.co.uk/itm/MYFORD-21-56T-BACKGEAR-CLUSTER-for-ML7-ML10-Direct-From-Myford/111169659910?You can see the same one herehttps://www.myford.co.uk/acatalog/B50.-21-56T-BACKGEAR-CLUSTER--70-1218-40.htmlThey do come up for sale from time-to-time as people break their old ones. The ML7 backgear is the same, so search for both.If you search for backgear broken tooth repair, you will see that people do repair these gears. I don't think it is simple, but people build them up with weld, or braze some steel on in the broken area. If you have an obliging engineering firm near you, you might take it in and see what they offer. Once you have some material in the gap, you can do a half-dece...

    see more »

    I'm afraid that the only one I can see at the moment is a full-priced one from Myford (£52.80)https://www.ebay.co.uk/itm/MYFORD-21-56T-BACKGEAR-CLUSTER-for-ML7-ML10-Direct-From-Myford/111169659910?You can see the same one herehttps://www.myford.co.uk/acatalog/B50.-21-56T-BACKGEAR-CLUSTER--70-1218-40.htmlThey do come up for sale from time-to-time as people break their old ones. The ML7 backgear is the same, so search for both.If you search for backgear broken tooth repair, you will see that people do repair these gears. I don't think it is simple, but people build them up with weld, or braze some steel on in the broken area. If you have an obliging engineering firm near you, you might take it in and see what they offer. Once you have some material in the gap, you can do a half-decent tooth profile with a file, etc - takes time, but can be done.This website gives two methods, the first would be beyond me, but the second looks possible!http://home.iprimus.com.au/stevor/gearrepairs.htm

    View Instructable »
    • Myford ML10 Lathe Oil Nipple Socket for Cone Pulley Lubrication
      83 views
      0 favorites
      0 comments
  • Servicing an Aqualisa Aquavalve 605/405 Shower Controller

    I'm sorry I can't remember the details :-(Would this (Aqualisa Replacement Cartridge) manual help you?http://www.free-instruction-manuals.com/pdf/pa_104...I believe that a new cartridge solves all (??) the dripping problems, so you might have to be prepared to go down that route at a bigger cost. However, if the O-ring set is still available at modest cost, that surely has to be worth a punt? I remember being very annoyed at my error (see step 3) - I glued the nut back together and reassembled the controller - it was easy to reassemble (having learned about not tightening it too much), but gluing nylon/plastic never works!!!! so I had to get the whole replacement cartridge.Given that warning, the servicing is pretty straightforward - its one of those things that a DIYer suffers - a prof...

    see more »

    I'm sorry I can't remember the details :-(Would this (Aqualisa Replacement Cartridge) manual help you?http://www.free-instruction-manuals.com/pdf/pa_104...I believe that a new cartridge solves all (??) the dripping problems, so you might have to be prepared to go down that route at a bigger cost. However, if the O-ring set is still available at modest cost, that surely has to be worth a punt? I remember being very annoyed at my error (see step 3) - I glued the nut back together and reassembled the controller - it was easy to reassemble (having learned about not tightening it too much), but gluing nylon/plastic never works!!!! so I had to get the whole replacement cartridge.Given that warning, the servicing is pretty straightforward - its one of those things that a DIYer suffers - a professional learns from each experience, but DIYers normally do these sort of things once only (so don't really learn from their experience). Give it a go!Best of luck

    View Instructable »
  • qthurtle's instructable Google Home & Alexa Mains Switch's weekly stats: 4 months ago
    • Google Home & Alexa Mains Switch
      78 views
      1 favorites
      0 comments
  • qthurtle's instructable Myford ML10 Lathe Chuck Soft Jaws's weekly stats: 6 months ago
    • Myford ML10 Lathe Chuck Soft Jaws
      404 views
      4 favorites
      3 comments
  • qthurtle commented on qthurtle's instructable Myford ML10 Lathe Chuck Soft Jaws6 months ago
    Myford ML10 Lathe Chuck Soft Jaws

    Many thanks - yep nothing innovative here - except the dimensions for the ML10 perhaps! Best wishes.

    View Instructable »
  • qthurtle completed the lesson Using a Slicer in the class Easy 3D Printing1 year ago
  • qthurtle completed the lesson Mitres in the class Table Saw Class1 year ago
  • Wiring up a Brooke Crompton single-phase lathe motor (Myford Lathe)

    I'm very sorry, but I have no experience of any other motor, so I can't help. Mine had four internal terminals not three, so I'm afraid I'm not going to be of any use to you!Best wishes - I hope you sort it out.

    View Instructable »