Gone West Posted October 16, 2019 Share Posted October 16, 2019 For my sewage treatment plant I have a semi-buried box containing the air pump and electrical conections. It has two warning lights on the lid one for an air pump fault and one for the holding tank liquid level being too high. Since connecting the sewage treatment plant to the shed consumer unit, there is no way of knowing if there is power getting to the sewage treatment plant other than to check in the shed. The MCB on the dedicated circuit for the sewage treatment plant or the RCD could trip without me knowing, causing problems with the holding tank backing up. The simplest solution would be to put another beacon on the lid, which is lit all the time there is power, to indicate a problem. Are there any other ways of indicating in the house that there isn’t power in the shed? Link to comment Share on other sites More sharing options...
Onoff Posted October 16, 2019 Share Posted October 16, 2019 Mr Cheap Seats here. Graft this to a similarly cheap, battery powered, wireless doorbell. https://www.amazon.co.uk/Wireless-Indicator-Detector-Pressure-Resistant/dp/B07Q61M64H/ref=asc_df_B07Q61M64H/? 1 Link to comment Share on other sites More sharing options...
Gone West Posted October 16, 2019 Author Share Posted October 16, 2019 41 minutes ago, Onoff said: Mr Cheap Seats here. Graft this to a similarly cheap, battery powered, wireless doorbell. https://www.amazon.co.uk/Wireless-Indicator-Detector-Pressure-Resistant/dp/B07Q61M64H/ref=asc_df_B07Q61M64H/? Thanks for that, it's a good idea, I didn't know they existed. Link to comment Share on other sites More sharing options...
Onoff Posted October 16, 2019 Share Posted October 16, 2019 (edited) 33 minutes ago, PeterStarck said: Thanks for that, it's a good idea, I didn't know they existed. Let's face it it's only a 230VAC relay held open when there's mains there. When power is lost the relays normally closed contacts shut triggering the 9VDC battery powered sounder. Easy to make from scratch with an ordinary electromechanical relay but always the chance it might stick over time...unlikely I guess. I'd maybe use an SSR if I was to make one I think. Very roughly it's this. 230 keeps the NC contact open. Lose it and sounder goes off. Replace sounder with small relay to trigger wireless doorbell: For £10 God knows what's inside. 2 pin plug btw so you need an adapter. Not an issue if your going to hack it! I've ordinary 230V contactors here and probably a wireless doorbell or two kicking around...no SSRs though... Edited October 16, 2019 by Onoff Stick not weld... Link to comment Share on other sites More sharing options...
Onoff Posted October 16, 2019 Share Posted October 16, 2019 (edited) Clever little emf detector here - no mains connection: http://www.circuitdiagram.org/contact-less-mains-power-failure-alarm.html Pretty much what I drew: https://www.electronics-project-design.com/PowerFailureAlarm.html Edited October 16, 2019 by Onoff 1 Link to comment Share on other sites More sharing options...
Temp Posted October 16, 2019 Share Posted October 16, 2019 At the other end of the cost spectrum...You can get devices that text you when power fails. Link to comment Share on other sites More sharing options...
Gone West Posted October 16, 2019 Author Share Posted October 16, 2019 18 minutes ago, Temp said: At the other end of the cost spectrum...You can get devices that text you when power fails. Now that's what Wendy wanted, but I think I prefer a tenner. 1 Link to comment Share on other sites More sharing options...
Onoff Posted October 16, 2019 Share Posted October 16, 2019 20 minutes ago, Temp said: At the other end of the cost spectrum...You can get devices that text you when power fails. Just knew someone would come along suggesting GSM! Next up...Pi...Arduino... ? Link to comment Share on other sites More sharing options...
Jeremy Harris Posted October 16, 2019 Share Posted October 16, 2019 I designed and built a wireless alarm for our treatment plant, and intended to offer it as a kit of parts here (went as far as buying all the components - they are sat here on the shelf, this is the old thread about it, with photos: https://forum.buildhub.org.uk/topic/225-ideas-for-treatment-plant-alarms/ ). I did mean to write the design of the thing up as a set of plans with the code etc, but it seems to be one of those things I've just not got around to doing! The thing uses two sensors, a pressure sensor that reads the pressure coming from the aeration pump, and a level sensor that detects if the effluent level in the pump chamber gets too high. It has a 433 MHz wireless link that sends data on it's status every few seconds to an indoor unit. The indoor unit both displays data on a small alphanumeric LCD and has a beeper for an alarm condition. This would work OK for detecting a power failure, as the pump pressure would drop if the power failed. 1 Link to comment Share on other sites More sharing options...
SteamyTea Posted October 16, 2019 Share Posted October 16, 2019 (edited) Could you not set up a simple device that just monitors power via a CT clamp. Be easy enough to work out which part is drawing what current if you really wanted to. Or just use a relay to close a GPIO pin. An RPi can send an email, or even a text (as long as it has a few minutes battery backup, along with the router) Edited October 16, 2019 by SteamyTea Link to comment Share on other sites More sharing options...
Gone West Posted October 16, 2019 Author Share Posted October 16, 2019 7 minutes ago, SteamyTea said: Could you not set up a simple device that just monitors power via a CT clamp After what @Onoff posted I did wonder about using a CT sensor rather than plugging into the circuit. Link to comment Share on other sites More sharing options...
Onoff Posted October 16, 2019 Share Posted October 16, 2019 1 hour ago, PeterStarck said: After what @Onoff posted I did wonder about using a CT sensor rather than plugging into the circuit. That little circuit I posted with the 4" pick up antenna is indirectly coupled to sense the mains. Just dug out a random wireless doorbell. Main problem is even if you keep your finger on the transmitter (CR2032 cell) button it doesn't continually sound the sounder (2 AAs). Contactor might be overkill but first I found with an NC contact! ? Link to comment Share on other sites More sharing options...
SteamyTea Posted October 16, 2019 Share Posted October 16, 2019 3 hours ago, Onoff said: That little circuit I posted with the 4" pick up antenna is indirectly coupled to sense the mains. Can it sense the strength of the field around the wire to a useful accuracy? Link to comment Share on other sites More sharing options...
Onoff Posted October 16, 2019 Share Posted October 16, 2019 Just now, SteamyTea said: Can it sense the strength of the field around the wire to a useful accuracy? Just enough I guess to sense "loss" of supply. The 1M pot is for sensitivity. Link to comment Share on other sites More sharing options...
Temp Posted October 18, 2019 Share Posted October 18, 2019 (edited) On 16/10/2019 at 15:32, PeterStarck said: Now that's what Wendy wanted, but I think I prefer a tenner. Cant find one for a tenner but £23 delivered.. Google found that Waytronic (who?) make a plug in adaptor that will SMS you on a power outage. It also monitors Temperature and Electricity usage plus a bunch of other functions.. http://en.waytronic1999.com/ProductsStd_221.html https://uk.banggood.com/WAYTRONIC-GSM-Smart-Power-Outlet-Plug-Socket-English-Russian-SMS-Remote-Control-Timing-Switch-Temperature-Controller-with-Sensor-p-1519750.html?gmcCountry=GB¤cy=GBP&createTmp=1&utm_source=googleshopping&utm_medium=cpc_bgcs&utm_content=garman&utm_campaign=pla-gbg-tools-pc&gclid=CjwKCAjwxaXtBRBbEiwAPqPxcBZi8at0WR2S1mlhgb5tyuKH99zKYwu20Bp4Bs-xvieXGf4j7wh-KxoC8YQQAvD_BwE&ID=6257627&cur_warehouse=CN https://www.aliexpress.com/item/32787412496.html Not used one myself so can't vouch for the product/supplier. Presumably it has a battery inside which might degrade over time? Also does it support 3G? 2G might get turned off? Quote Features: Insert GSM SIM card to use. Only support GSM SIM card, not support CDMA. Send SMS command to control socket. Temperature sensor included. Temperature measurement function. Electricity consumption measuring function. Can send sms to query how much electricity used. SMS notification when power failure and power recovery. Delay control and timing control function. Remotely query environment temperature. Temperature control and sms notification function. (Within the specified temperature, if beyond or below the range of values, it will stop working and send sms notification.) Can set 1 master number and multiple family numbers. SMS language: Russian or English. Suitable for the electric appliance within 2200W. One 5V USB output interface. Built in buzzer, to prompt the switch on or off and alarm prompt (can send sms command to turn on this function). Edited October 18, 2019 by Temp 1 Link to comment Share on other sites More sharing options...
PeterW Posted October 18, 2019 Share Posted October 18, 2019 There are plenty on Alibaba ... however purchasing from the King Pigeon Communication Company may be at your risk .... Link to comment Share on other sites More sharing options...
ToughButterCup Posted October 18, 2019 Share Posted October 18, 2019 On 16/10/2019 at 14:18, Onoff said: [...] Easy to ... [...] You lost me after the word 'Easy ... ' Link to comment Share on other sites More sharing options...
ToughButterCup Posted October 18, 2019 Share Posted October 18, 2019 On 16/10/2019 at 14:18, Onoff said: [...]Lose it and sounder goes off. Replace sounder with small relay to trigger wireless doorbell: [...] ... 'old on a minnit... You mean every time you lose power, your poor wife has to get up from her comfortable armchair seat and find that nobody's rung the doorbell? Good luck with that. I'd get marmalised .... Link to comment Share on other sites More sharing options...
Onoff Posted October 18, 2019 Share Posted October 18, 2019 2 hours ago, AnonymousBosch said: ... 'old on a minnit... You mean every time you lose power, your poor wife has to get up from her comfortable armchair seat and find that nobody's rung the doorbell? Good luck with that. I'd get marmalised .... Even the cheapo door bells have multiple tunes. Say Knock Three Times for the doorbell..... 1 Link to comment Share on other sites More sharing options...
Onoff Posted October 18, 2019 Share Posted October 18, 2019 Here you go Peter, little video of a nice and simple chunky contactor to give you a volt free set of contacts to do "something" if you lose power. Amber beacon in the shed window run off a solar trickle charged battery? 1 Link to comment Share on other sites More sharing options...
Onoff Posted October 18, 2019 Share Posted October 18, 2019 Ideal transmitter and receiver circuits here methinks: https://www.nutsvolts.com/magazine/article/cheap-and-dirty-wireless-remote-control Transmitter constantly transmits and receiver has an LED and relay output. I wonder if those cheap as chips Chinese RF modules @ProDave got from China could be substituted for the Radiometrix modules? Link to comment Share on other sites More sharing options...
ProDave Posted October 18, 2019 Share Posted October 18, 2019 I bought a very cheap 433MHz transmitter and receiver modle from China on ebay, cost less than £3 for the pair. Link to comment Share on other sites More sharing options...
Onoff Posted October 19, 2019 Share Posted October 19, 2019 (edited) 10 hours ago, ProDave said: I bought a very cheap 433MHz transmitter and receiver modle from China on ebay, cost less than £3 for the pair. I always struggle understanding those little RF modules as in how to interface them to something "real" like a relay so I've always avoided them. I thought that nutsvolts circuit link really useful. Have you the link again please for those modules you bought? Edited October 19, 2019 by Onoff Link to comment Share on other sites More sharing options...
Onoff Posted October 19, 2019 Share Posted October 19, 2019 Are there any cheap Chinese, direct equivalents for these TX & RX modules? Link to comment Share on other sites More sharing options...
ProDave Posted October 19, 2019 Share Posted October 19, 2019 1 hour ago, Onoff said: I always struggle understanding those little RF modules as in how to interface them to something "real" like a relay so I've always avoided them. I thought that nutsvolts circuit link really useful. Have you the link again please for those modules you bought? This is the transmitter unit I used https://www.ebay.co.uk/itm/433Mhz-Wireless-Transmitter-EV1527-Learning-Code-Encoded-for-Arduino-AVR/292030436727?hash=item43fe5ed577:g:QwkAAOSwB-1YpWii You simply choose a code with the jumpers, then when you apply 5V dc, it transmits. This is the receiver. https://www.ebay.co.uk/itm/1-Channel-Wireless-Relay-433MHz-RF-Remote-Control-Switch-Receiver-SRD-DC12V-10A/192470066162?hash=item2cd01c23f2:g:uJAAAOSwSfNal7~H This runs from a 12V dc supply. The first time you use it, you turn your transmitter on and then press the button on this module, that teaches it your chosen code. Thereafter you leave the receiver powered, and whenever your transmitter is turned on, this receiver module energises it's changeover relay that you can use to switch anything. There are plenty of other variations on this theme available. 1 Link to comment Share on other sites More sharing options...
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