Recent content by Jeremy Harris

  1. J

    08M2 EEPROM Life span

    The schematic and code is in this thread on the Endless Sphere forum: https://endless-sphere.com/forums/viewtopic.php?f=2&t=22675 It works much as @hippy suggested earlier.
  2. J

    Particulate sensor interface to any Picaxe

    I'm currently updating my old Picaxe based environmental data logger, that up until now has only measured temperature, relative humidity and carbon dioxide concentration. There are now some affordable particulate sensors that can measure the three main particulate sizes of concern as fair as...
  3. J

    32-bit maths routines for BMP180, BMP280 and BME280 Atmospheric sensors.

    Just as a word of caution, DO NOT buy the 6 pin packages either from a UK or overseas seller. As mentioned above, these are fakes, beyond any doubt. I bought some modules advertised as being BME280 breakout boards from a UK seller, that specified that they measured temperature, pressure and...
  4. J

    What is the basics for SMD soldering

    Thanks for posting that, those soldering skills are pretty impressive! The only observation I'd make is that it's a technique that would only work on a board with a solder mask; I'm not sure it would work well with a plain, home etched board.
  5. J

    Baud rates below 600?

    I can't see anything in the manual or the online help about slowing the clock further (say, setfreq M2) and whether this then allows 300 baud as the minimum, rather than 600 baud with a 4MHz clock which is as slow as I can go according to the manual. I'm not in a position to do a quick and...
  6. J

    Borehole well water level sensing

    The camera rig looked like this: And was made from an old underwater UAV camera housing I'd scrounged from a scrap pile years ago (which had no camera in it). I fitted an old car reversing camera I had, made up an LED lighting ring (had two goes at this, as the first was just a bit too...
  7. J

    Borehole well water level sensing

    Thanks for all the advice - it's noticeable that the practical knowledge all comes from friends here from the US! This mirrors my experience in trying to get good advice here in the UK - it seems so few people live "off grid" in terms of not having a mains water supply here that there really...
  8. J

    Borehole well water level sensing

    Almost certainly, but I think there are a couple of problems with this idea. The first is that the conductivity of the earth varies a fair bit, and may well swamp the effect of a change in water level. The second is that the conductivity of an immersed bare wire will change with time, as it...
  9. J

    Borehole well water level sensing

    The pipe is actually 125mm OD, and 119mm ID, I think, so 3mm wall thickness, and made from PVC. For interest, it comes in 3m long sections, with Acme threads on the ends (internal one end, external the other) and the lowest 4 sections have a slotted filter, in that the pipe has vertical slits...
  10. J

    Borehole well water level sensing

    On another thread I took things off topic by looking at ways to measure water level in a borehole well. This thread is to hold those posts moved by admin (I hope) so please don't add posts here until the old posts have been moved over. The challenge I have is wanting to measure the depth of...
  11. J

    Windows - off topic

    I can foresee an unintended, probably massively under-reported, issue arising here. I don't think I'm alone in having grave reservations about the way that Microsoft have switched their business model. All companies need a revenue stream, but Microsoft (and others) have realised that the...
  12. J

    Serial relay module

    Sadly I've found some bugs in the way these modules report back data, or it may be me not understanding the Chinese instructions well enough. I've put together a first stab at a datasheet for them, that highlights the bugs and what I've found so far. In theory, they should work OK with several...
  13. J

    Transformerless power supply problem

    I agree, I do hope that shah_siddiquee isn't put off or offended by all the critical comment about these supplies. I agree wholeheartedly with your post, fernando_g, and remember similar radio and TV sets we had over here that had a live chassis. We also had a pretty lethal mains power system...
  14. J

    Serial relay module

    Whilst looking for something unrelated, I came across these cheap serial addressable relay modules: http://www.banggood.com/One-Channel-Relay-Module-Intelligent-Custom-Command-Control-Serial-Control-Multi-Mode-Level-Trigger-p-1077655.html From what I have been able to decode from the...
  15. J

    Can the 14m2 directly control a latching relay with a 5V 20ma coil?

    It seems to be working fine on 10µF, no different to the 150µF that I first tried. I shall have to dig around and see if I can find anything smaller; I may have some 4.7µF capacitors around. I'm not sure about leaving the back EMF diodes out or not. In theory the internal clamp current may be...
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