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Advice needed Miniature Temperate Change Warning Device


New Member
I need a monitoring device that will give a beeping warning when the surface of the electronic monitor is either wet or the the temperature raises above a certain set point. The sensor will give a warning with a change in it's condition and will sit in an enclosed container. I envisage the other electronic components needed will be contained in a plastic container no larger than L 7cm X W 5cm X Depth 3 cm.

If I can use a comparison in an effort to explain what I need. Many kids toys have a similar electronic mechanism contained in a small rectangular box that when you touched the toy somewhere it spoke or barked. The device I am after will emit a beeping warning once the sensor is activated.

I know very little about electronics but my research to date has shown me that the likely parts required to produce what I am after seem readily available and reasonably priced.

I am posting here not to get a freebee, but hoping someone will be able to point me in the right direction of a person or business that may help me using their knowledge of electronics put this together. I have trolled the internet for some time now and have come across numerous businesses selling electronic components but have not found any offering a service to actually put it all together.

Any suggestions or leads in this respect would be greatly appreciated.


Active Member
Maybe this should be posted in "Jobs and Careers". More info on what is required would be helpful.
In the meantime read up on Arduino and it 's versatility. The A has many plug-in units (called shields) and program routines (called sketches). The Arduino system is easy to learn and master. E


New Member
Thank you very much for your reply to my enquiry. I believe I will take your advice and post what I require in "Jobs and Careers' when I have more detailed specs. Maybe someone on the forum will be able to assist me. For the record, my initial enquiry came about due a major life-stlye change I have recently had due to a cancerous prostrate operation and with it the constant incontinency problems I have experienced since. I desperately want to change my situation.

Part of my solution involves coming up with a compact warning device that I can easily attach to the body that will alert me to the presence of urine. Basically, it would consist of a some type micro sensor, an Arduino board (if suitable) and a small speaker which would let out a small buzzer type warning signal anytime it comes into contact with urine. I am presently researching the most appropriate and reliable micro sensor to provide the necessary signal that would only activate in the presence of urine and would return to normal monitoring once it is removed. When I find that sensor and the type of signal that it generates I will post again under Jobs as suggested.
Again thanks for prompt your reply.

Les Jones

Well-Known Member
Most Helpful Member
You have not given any details of the temperature at which the sensor is required to change its output state. (Or how accurate this value needs to be.) As you also mention sensing moisture I assume the temperature to be somewhere between 0Deg. C and 100 Deg. C. If this assumption is correct then a thermistor connected to one input of a comparator (such as an LM393) with the other input connected to a variable voltage reference my be good enough. To detect moisture some closely spaced tracks on a piece of PCB connected to a comparator may be good enough. Just using copper tracks on the PCB will probably suffer with corrosion so some kind of plating would be required. There are other methods to detect moisture but thy would be more complex.


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