Radian Posted June 30, 2022 Share Posted June 30, 2022 5 hours ago, SteamyTea said: I always liked astable multi vibrator He speaks very highly of you too. But yes, that was my first thought. Something like: Sim shows 50V spikes at around 10 times a second for 200uA input current @0.8V Not sure that circuit would behave exactly the same for real. Quite a lot of component value juggling to get bursts of HV like that. It would more naturally have a tendency to settle out at a constant square wave at lower voltage i.e. around 10V. But that would probably feel similarly unpleasant to a slug. Link to comment Share on other sites More sharing options...
Radian Posted June 30, 2022 Share Posted June 30, 2022 Had a go at making it but not really getting anywhere. I guessed at a 500 Ohm source impedance for the zinc/copper ground spikes but the ones I made came in at five times as much. With such a high impedance the capacitor doesn't charge up enough to turn on the transistor bases (>0.6V). The collector resistors bleed off too much current. It works fine with an AA battery though - but defeats the object of using the bimetallic battery principle. If I had some very low threshold mosfet transistors that could possibly work but my lowest Vgs devices are all over 1V. 1 Link to comment Share on other sites More sharing options...
Onoff Posted June 30, 2022 Share Posted June 30, 2022 8 hours ago, Radian said: Did you copy the same photo by mistake, both multimeter shots look the same (0.826V) I was wondering about getting a bit more voltage to begin with, although I think I can get a simple two-transistor oscilator running off of 0.8V. Yep, copied the same photo. Here's the one showing two pots in series with 1.6VDC. Constraints being surface area / available depth. I could try two zinc and two copper electrodes in the same pot... Last time I measured my own 4' long / 3/8" dia rod (TT) I got I think 47 Ohms from memory as an aside. For bigger battery fun I'm debating proper, copper clad rods for one electrode and zinc plated studding for the other. Maybe make a "pond" up, fed by the kitchen grey water to keep topping up the electrolytes? I'll get bored soon! Link to comment Share on other sites More sharing options...
Radian Posted June 30, 2022 Share Posted June 30, 2022 9 minutes ago, Onoff said: Last time I measured my own 4' long / 3/8" dia rod (TT) I got I think 47 Ohms from memory as an aside. A tiny bit more surface area for sure! But 1.6V would be fine if it's got a source resistance low enough... If you have a resistor handy, somewhere between 470 and 1K Ohms, then measure the voltage you can develop across it. As you know from Ohms law, knowing the voltage across a resistor tells you the current flowing through it: I=V/R Then knowing how much voltage was dropped from the open-circuit voltage (1.65V in your case minus whatever you read across your test resistor) and dividing that by the resistor current, will tell you the source impedance: R=V/I Hopefully under 500 Ohms. Link to comment Share on other sites More sharing options...
Onoff Posted June 30, 2022 Share Posted June 30, 2022 Noticed tonight little black insects on the stalks of some of the 50 runners. Is this "black fly" I've about? The ants seem interested in them. Do I need to do something about them? Link to comment Share on other sites More sharing options...
Gone West Posted July 1, 2022 Share Posted July 1, 2022 (edited) 13 hours ago, Onoff said: Noticed tonight little black insects on the stalks of some of the 50 runners. Is this "black fly" I've about? The ants seem interested in them. Do I need to do something about them? They are blackfly and the ants eat the secretions from the blackfly. The ants will carry the blackfly to other parts of the plant and effectively farm the blackfly. The best way to get rid of them is to encourage blue tits which will eat the blackfly and ants and also blackbirds which will the ants. https://www.rhs.org.uk/biodiversity/blackfly Edited July 1, 2022 by Gone West Added link Link to comment Share on other sites More sharing options...
SteamyTea Posted July 1, 2022 Share Posted July 1, 2022 6 minutes ago, Gone West said: encourage blue tits I did that and got told off. Link to comment Share on other sites More sharing options...
Onoff Posted July 1, 2022 Share Posted July 1, 2022 2 hours ago, Gone West said: They are blackfly and the ants eat the secretions from the blackfly. The ants will carry the blackfly to other parts of the plant and effectively farm the blackfly. The best way to get rid of them is to encourage blue tits which will eat the blackfly and ants and also blackbirds which will the ants. https://www.rhs.org.uk/biodiversity/blackfly Read that too thanks. Sort of puts the mockers on netting the whole plot off! I'm going to try an artist's brush to knock them off then a few drops of peppermint essential oil in a plant sprayer full of water. 1 Link to comment Share on other sites More sharing options...
saveasteading Posted July 1, 2022 Share Posted July 1, 2022 Encourage ladybirds. Check what the larvae look like so you don't remove them The easy solution is to wash the blackfly off with a hose spray. They don't have much grip and if they can climb up again (I doubt it) then they are slow and you do it again. The ants will protect them. Link to comment Share on other sites More sharing options...
Onoff Posted July 1, 2022 Share Posted July 1, 2022 Well that's exciting...not. Rubbing blackfly off the bean stalks and leaves then spraying with a few drops of peppermint oil in a plant sprayer full of water. Seem to have cleared a lot though. 1 Link to comment Share on other sites More sharing options...
Onoff Posted July 19, 2022 Share Posted July 19, 2022 Seemingly now clear of blackfly. Not sure if it's because of my efforts with manually getting rid, the accompanying dusting with peppermint spray oil or that I now have spiders and ladybirds living on the plants. Probably a combination. No beans yet but a good few flowers. 1 Link to comment Share on other sites More sharing options...
SteamyTea Posted July 25, 2022 Share Posted July 25, 2022 Got a bean. 3 Link to comment Share on other sites More sharing options...
saveasteading Posted July 25, 2022 Share Posted July 25, 2022 Hoorah. Some varieties are ready at that stage. Others when the beans inside are starting to plump out. You might need to pick that one anyway and just chuck it into some continental type stewey thing. We have only one plant producing at present, but have had 4 portions from it this week. Plus one marrow (from being away) 7 courgettes, 4 cucumbers and 2 tomatoes. Hardly a glut. But we were away 3 weeks, there was no rain and the irrigation machine failed. I forecast that a week from now you will have too many. Link to comment Share on other sites More sharing options...
Onoff Posted July 25, 2022 Share Posted July 25, 2022 59 minutes ago, SteamyTea said: Got a bean. Yours is a lot bigger than mine. Bean eating the dwarf ones here in the pots. The runners in the bed are just a couple of inches long at best but lots of them. The potted runners are lagging! Link to comment Share on other sites More sharing options...
SteamyTea Posted July 25, 2022 Share Posted July 25, 2022 1 minute ago, Onoff said: Yours is a lot bigger than mine So what have we learnt. My low tech (pot of mud, home grown bamboo sticks, and some old bean seeds from the back of the useful draw, plant, water and forget. Or your high tech methods? Link to comment Share on other sites More sharing options...
Onoff Posted July 25, 2022 Share Posted July 25, 2022 16 minutes ago, SteamyTea said: So what have we learnt. My low tech (pot of mud, home grown bamboo sticks, and some old bean seeds from the back of the useful draw, plant, water and forget. Or your high tech methods? Oi! I'm a late starter! What have I learnt? Control the blackfly earlier for a start. I don't seem to have many flowers "low down" tbh. Were they destroyed early on before I properly got on top of the blackfly? The layered trench though seems to be holding moisture well, see how dark the soil is in comparison: These are about the biggest runners in the trench at the mo. I've plenty it seems in the upper layers of the foilaige: The potted runners...well, not even worth taking an in focus photo: 1 Link to comment Share on other sites More sharing options...
Onoff Posted August 1, 2022 Share Posted August 1, 2022 I think we have beans: 1 Link to comment Share on other sites More sharing options...
Roundtuit Posted August 1, 2022 Share Posted August 1, 2022 Fantastic! Keep picking them young though or they'll soon get away from you. Link to comment Share on other sites More sharing options...
Onoff Posted August 1, 2022 Share Posted August 1, 2022 3 minutes ago, Roundtuit said: Fantastic! Keep picking them young though or they'll soon get away from you. You mean they'll "runner" way? Link to comment Share on other sites More sharing options...
Roundtuit Posted August 1, 2022 Share Posted August 1, 2022 5 minutes ago, Onoff said: You mean they'll "runner" way? You're not getting a laughing emoji for that... Link to comment Share on other sites More sharing options...
saveasteading Posted August 1, 2022 Share Posted August 1, 2022 30 minutes ago, Onoff said: we have beans Excellent . One of them poss slightly bigger than optimum. Do they have a 'runner' fibre along the length that has to be removed. or do they snap clean in two? 26 minutes ago, Roundtuit said: they'll soon get away from you Better picked and discarded than allowed to grow mature, as the plant will make seeds instead of feeding you. Until the last few anyway, when you leave them and collect next years seeds. Link to comment Share on other sites More sharing options...
SteamyTea Posted August 1, 2022 Share Posted August 1, 2022 (edited) I need to crop mine tomorrow. Edited August 1, 2022 by SteamyTea Link to comment Share on other sites More sharing options...
Onoff Posted August 1, 2022 Share Posted August 1, 2022 4 hours ago, saveasteading said: Excellent . One of them poss slightly bigger than optimum. How long then is optimum? Beans, that is... Seem to remember my old man's runners being about a foot long. Link to comment Share on other sites More sharing options...
SteamyTea Posted August 1, 2022 Share Posted August 1, 2022 4 minutes ago, Onoff said: Seem to remember my old man's runners being about a foot long. I think it depends on the cultivar. Scotch beans will probably grown to a yard long, taste fine after a weeks boiling. 1 Link to comment Share on other sites More sharing options...
Marvin Posted August 2, 2022 Share Posted August 2, 2022 10 hours ago, SteamyTea said: I think it depends on the cultivar. Scotch beans will probably grown to a yard long, taste fine after a weeks boiling. I presume you got your taste buds shot off in a war.... Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now