DMM continuity tester for the hard of hearing - Page 1
Forum section: electronics / testgear

author: cyb3rphil
author_rank: Contributor
timestamp: February 18, 2020, 10:41:36 pm
content: Hi all,can't really say that I've been a long time lurker here but I've visited this forum relatively often so far, though now I decided to jump aboard as well especially since I need some recommendations that I'm sure a handful of you guys could help me with.I'm hearing impaired (deaf on the left ear, hard-of-hearing on the right) and have trouble hearing continuity beepers from multimters in an industrial (noisy) environment at work. I can barely hear the Benning MM 5-2 that I got provided by my company if some machinery is running nearby. Since that's not really a good thing, I spoke with my boss about the issue and he said I could have a different meter.The question now is which meter to choose. It doesn't need to be a full blown electronics meter with insane accuracy and stuff but rather an electrician's one like the Fluke 115 or 117 or the Benning MM 5-2. Ideal would be a very visible visual indicator like a bright LED or flashlight or something (a tiny NCV LED isn't gonna cut it if you can't place the meter in your direct field of view inside a switch cabinet) and a very loud and distinguishable beeper. When it's somewhat loud around me the beeper sounds like just another piece of machinery going and I sometimes even think it beeps while it actually doesn't or vice versa. But I want a meter that I can be confident in knowing when it's detecting continuity!Also, I have never seen a meter be advertised specificly for its continuity tester. Almost every webshop says things like "Continuity tester - yes" but not "Continuity tester - yes, beep and NCV LED". That way it's really hard to pick out a good one.What do you think of Keysight's UT1232A? I saw in videos of it that it flashes the LCD backlight, is that thing bright and easy to see in bright environments? The meter has a flashlight, it doesn't light up in continuity right? How loud is the beeper? My Fluke 179 is my loudest meter, how does the UT1232A compare to that?What other meters could I look at?Cheers, Philip

author: Muttley Snickers
author_rank: Unknown
timestamp: February 18, 2020, 11:35:21 pm
content: Quote from: cyb3rphil on February 18, 2020, 10:41:36 pmThe model you refer to is the Keysight U1232A and they appear to be a very good little meter with many features and functions. The selector switch integrity and robustness of that series might be of concern to some as discovered by member joeqsmith. Keysight do back their products with a very good warranty though.Another smaller meter with a very good feature set including an illuminated continuity display is the Brymen BM235 and many here own the EEVblog branded model. There may be other brands and models which incorporate an illuminated or flashing continuity display but either of the two mentioned should be suitable.

author: cyb3rphil
author_rank: Contributor
timestamp: February 19, 2020, 11:34:14 am
content: Brymen BM235, added that to the list of consideration, thanks!It seems to have a bright backlight which helps a lot, it doesn't need to be blinking like the U1232A one does. The Keysight also seems darker but that might as well just be because it's orange. Another advantage is its much lower cost (the Keysight is slightly too expensive but if it's the best option I'll try convincing my boss). However it's beeper seems to be quieter than other meters, in a video joeqsmith compared it to a Fluke 115 which I know is a bit quieter than my 179. That's not ideal since it still should be usable conventionally imo.

author: Muttley Snickers
author_rank: Unknown
timestamp: February 19, 2020, 12:54:45 pm
content: Out of curiosity I just put a Fluke 117 alongside the Brymen BM235 and the Fluke has a much louder lower pitched tone, for my hearing this much more appealing than the higher pitched tone on the Brymen.For comparison I could record and post an mp3 of both these meters continuity beepers in the morning. I suspect that the audible levels and frequency may vary even on exactly the same model due to tolerances, so my BM235 could sound slightly different to joeqsmith's.

author: dprylows
author_rank: Newbie
timestamp: February 19, 2020, 02:17:22 pm
content: I have keysight, agilent and fluke meters. The flukes are the only ones that I can hear the continuity beeper on. I wear hearing aids in both ears.

author: Fungus
author_rank: Super Contributor
timestamp: February 19, 2020, 02:43:16 pm
content: I've always wanted one with a light on the probe.Looking at the screen of the meter and at what I'm probing just doesn't work very well unless you can get the meter right next to the job.

author: Muttley Snickers
author_rank: Unknown
timestamp: February 19, 2020, 03:11:39 pm
content: Quote from: Fungus on February 19, 2020, 02:43:16 pmBe careful what you wish for.https://www.eevblog.com/forum/dodgy-technology/vion-the-worlds-silliest-multimeter/

author: GerryR
author_rank: Frequent Contributor
timestamp: February 19, 2020, 03:12:43 pm
content: Quote from: Fungus on February 19, 2020, 02:43:16 pmThat is an excellent idea! A light in the probe would really change the meter market. Someone would actually have to come up with something new rather than "me too" products. Excellent thinking out of the box!

author: schmitt trigger
author_rank: Super Contributor
timestamp: February 19, 2020, 04:25:59 pm
content: Would you be open to the idea of building a simple continuity tester to complement your DMMs?The circuit should not be too difficult: a constant current source with a diode-clamped output (to limit open circuit voltage) followed by a comparator.The comparator's output, with a suitable transistor, could drive a high brightness LED and/or a loud buzzer. Or even perhaps a small vibrator motor.To calibrate it, purchase an inexpensive -let's say- 1 ohm, 1% resistor. Adjust the comparator threshold to barely detect the resistor.

author: Fungus
author_rank: Super Contributor
timestamp: February 19, 2020, 04:33:26 pm
content: It would be easy to build something with lights/buzzers/chair vibration that has no input protection.Something that could be hooked up to 230V AC and survive? A bit more difficult.

author: cyb3rphil
author_rank: Contributor
timestamp: February 19, 2020, 05:04:27 pm
content: Quote from: Muttley Snickers on February 19, 2020, 12:54:45 pmLouder volume and lower frequency is generally better especially since when people get old they tend to hear higher frequencies less good. For the hearing impaired, it depends. Some can hear higher frequencies better, some lower, and some are inbetween. That's why I like that you can adjust the buzzer frequency on the keysight.Quote from: dprylows on February 19, 2020, 02:17:22 pmTo me my older Uni-T UT61D is barely audible, if the unit is more than about half a meter away from me or not to my right I can forget about doing continuity tests with it. Friend of mine hears it like 10 meters away around 2 corners in the hallway. He does have very good ears but I still can't really comprehend how he does that.Quote from: Fungus on February 19, 2020, 02:43:16 pmWell said. It's kind of like having a slow reacting buzzer with the added hurdle of waiting until the reading somewhat stabilizes and interpreting the result.There's two-pole voltage testers (we call them Duspol here) that have continuity testers built in but then again it's only one probe that lights up and most of them have a longer start-up time from off to detecting continuity and sounding the buzzer.I can imagine illuminated test leads to be relatively expensive and additional conductors for the LED (which could even be a bicolor one for indicating things) would make the lead itself more thicker and less flexible. And CAT III/IV rating a probe isn't made easier by putting additional electronics in it. Oh and, the lead wouldn't fit in standard 4mm jacks as there has to be another connection for the LED, which means the lead is proprietary to a specific meter and can't be used anywhere else.If it were easy, why aren't there any probes with built in flashlights?Quote from: schmitt trigger on February 19, 2020, 04:25:59 pmTechnically yeah, but then it's an additional device to keep around, as the DMM is still needed for voltage and resistance etc.And as Fungus said, accidentally hooking that up to 230V or even 400V isn't going to be fun and then we end up in liability issues (because it's not a device from the company, who's responsible for the accident etc) and other stuff I don't wanna be involved in.Quote from: Fungus on February 19, 2020, 04:33:26 pmVeeeeeery interesting idea. lol - nobody's gonna tell me they can miss that. However I'd rather have the probe vibrate lightly in my hand (this sounds kinda inappropriate) since I rarely work while sitting. Having a vibrating chair sounds kinda cumbersome too, since you can't take it anywhere else as easily as a handheld DMM.

author: AVGresponding
author_rank: Super Contributor
timestamp: February 19, 2020, 06:14:29 pm
content: I wonder how easy it would be to piggy-back a small bluetooth module inside a DMM, connected to the continuity buzzer/beeper.Paired with bluetooth headphone/s, you could have it as loud as you like, and since the module inside the meter wouldn't have any connections to the meter's test probes, it should avoid the safety issues.

author: cyb3rphil
author_rank: Contributor
timestamp: February 19, 2020, 07:10:38 pm
content: Some hearing aids are bluetooth capable, so they could connect directly. Something like this should definitely include a volume and frequency or tone pattern (continuos/pulsed) for individual adjustment.A bluetooth DMM could also be connected to a phone that triggers a very visible indicator on the screen or the phone's flashlight. I know there's apps that connect with meters to show the measurements, but is there anything like I described? And how fast is it? I don't wanna wait a second before the screen says "yep, there's a connection".By the way, hearing aid users that are practically deaf without it (like me) can't really use headphones. With hearing aid it will cause feedback like if you bring a microphone close to a speaker outputting its signal. Without it everything's too quiet.

author: AVGresponding
author_rank: Super Contributor
timestamp: February 19, 2020, 07:27:17 pm
content: I've no idea if any meter comes with this kind of bluetooth functionality, but I reckon it would be widely useful.I have better than average hearing for my age, but there's plenty of times when my working environment is so noisy I can't hear my Fluke T5-1000's continuity buzzer.Maybe Dave could add it in his $150 meter...EDIT: Just ordered one of thesehttps://www.ebay.co.uk/itm/Bluetooth-4-1-Stereo-Audio-transmitter-Module-Board-GFSK-Wireless-Transceiver-UK/133275129999, going to experiment...

author: cyb3rphil
author_rank: Contributor
timestamp: February 19, 2020, 08:03:05 pm
content: Looks interesting! I'm gonna keep an eye open for your results.One might also be able to add a DIY board that reads the beeper signal and drives a bright LED that you could hack onto the meter. I'm thinking a small COB so it's still visible in bright environments.If that's a new meter Dave is developing (not the 121GW) and it has some of the features that I'd like in a good meter (backlight continuity indicator, adjustable frequency/tone pattern) I'm gonna be one of the first buyers.

author: AVGresponding
author_rank: Super Contributor
timestamp: February 19, 2020, 09:19:36 pm
content: Since it's coming from China, it'll be a while getting here I suspect...The trick with any of these hacks is to make sure you don't impact the CAT rating in any way, given that you want to use it in a working environment, so you'd have to make sure your LED was visible without modifying the casing.If there's translucent buttons to place it near to, that might work ok, probably best visibility if you can get it near to the LCD.Now I'm wondering how easy it would be to implement a bi-colour LED in place of the standard backlight

author: TheSteve
author_rank: Unknown
timestamp: February 19, 2020, 10:08:06 pm
content: Some of the Keysight meters do allow you to select from several different frequencies for the continuity beeper, that could help in some cases.

author: threephase
author_rank: Regular Contributor
timestamp: February 20, 2020, 03:41:20 pm
content: It may not suit your work flow, but when I am working on electrics, my go to tester is something like a Fluke T110 voltage / continuity tester, other makes are available of course. This has both audible and visual signals for the continuity and also an LED torch on one of the probes.There are also versions with a digital display, if you want actual values and not just LEDs showing a range.Kind regards

author: cyb3rphil
author_rank: Contributor
timestamp: February 20, 2020, 06:37:37 pm
content: Quote from: ThickPhilM on February 19, 2020, 09:19:36 pmSomething like they're doing with wireless charging? That might affect the meter circuitry though and draw a lot of power from the battery.Quote from: TheSteve on February 19, 2020, 10:08:06 pmThat's exactly what I like about the Keysight. It's only four of them on the U1232A and all of them are somewhat high (lowest is 3.2 kHz iirc), but still. Plus it has the backlight come on at the same time.Quote from: threephase on February 20, 2020, 03:41:20 pmThis sounds like the best option so far. Some testers also vibrate (ie. the Fluke T130), I don't know if they vibrate when they detect continuity though. Either way I'd rather use a multimeter than a voltage tester for general electrics, but that's personal preference. And a voltage tester doesn't replace a meter (it doesn't measure current or high resistances or diode test) but - I know you normally shouldn't - in case you don't have a tester at hand, a meter will prove dead in a pinch as well if you confirm it working beforehand and afterwards.

author: threephase
author_rank: Regular Contributor
timestamp: February 21, 2020, 09:04:38 am
content: Quote from: cyb3rphil on February 20, 2020, 06:37:37 pmThe T110 / T130 / T150 only vibrate during voltage detection when the low impedance function is in use. For high impedance voltage measurements or continuity they do not vibrate. No, they do not have the same functionality as a DMM, so if end up carrying both around then it becomes a nuisance.Technically speaking there is nothing wrong with using a DMM to test for dead using the process you have stated. The issue revolves around the potential for user error when using a DMM that a voltage tester mitigates against. I work on high energy circuits where the error with a DMM tends to lead to a 'goodnight Vienna' scenario, so the use of a DMM is prohibited without good reason. If you are working on lower energy circuits without high pressure from management to complete the work, then use of the DMM could be acceptable.You can always increase the safety factor with the DMM for voltage measurement by using fused test probes, but that of course can create its own issues.Kind regards

author: Muttley Snickers
author_rank: Unknown
timestamp: February 21, 2020, 09:48:00 am
content: I bought a really cheap fitness band recently which has a brilliant display and vibration alerts and wonder whether it could be somehow adapted or customised to communicate with a bluetooth multimeter.Currently it communicates with my phone via an application but if it could display even a basic reading from a multimeter or perhaps vibrate for continuity then I think some might find this useful.

author: nowlan
author_rank: Frequent Contributor
timestamp: February 21, 2020, 10:24:41 am
content: There are some talking multimeter hacks. Either rs232 or bluetooth. Not really suitable for mains voltage. More vision impaired hacks.As mentioned above, some hearing aids have blutooth connection now. maybe a box inbetween.Sorry had add any more about real meters.

author: nfmax
author_rank: Super Contributor
timestamp: February 21, 2020, 11:27:13 am
content: Hmmmm...Now if you used clear silicone rubber for the lead insulation, and designed a special shrouded 4mm jack plug and socket, you could couple light from an indicating LEDin the meter itself, and the whole lead would light up as an indication. Probably white for continuity, and maybe also red for voltage above the SELV limit. Any innovative DMM manufacturers out thre?

author: GerryR
author_rank: Frequent Contributor
timestamp: February 21, 2020, 11:50:19 am
content: Quote from: TheSteve on February 19, 2020, 10:08:06 pmI have one that changes frequencies, but the intensity (loudness) is what needs to be changed. There isn't much difference in range of the frequencies you have to choose from. A low growl would be more effective in the industrial environments that I have worked in. IMO. Perhaps the designers should spend some time using their meters in different environments; they might come up with something more useful. Just a thought.

author: tooki
author_rank: Super Contributor
timestamp: February 21, 2020, 01:19:53 pm
content: Quote from: nfmax on February 21, 2020, 11:27:13 amI don’t think clear silicone alone would work (insofar as I think only a short amount of it would light), but one could certainly do what they do in light-up USB cables: fiber optics. They put in a few fibers which have nicks or scuffed spots every so often for light to escape from, such that the whole cable lights up.I think it’d make more sense to have a fiber run all the way to the probe tip and just light a ring there. Looking at the cords themselves doesn’t make a lot of sense to me.

author: cyb3rphil
author_rank: Contributor
timestamp: February 21, 2020, 02:59:29 pm
content: Quote from: nowlan on February 21, 2020, 10:24:41 amI feel that hearing disabilites are the most often overlooked disability. Not to make my fate sound worse but - most people just say "just turn the volume up" but you can't "just walk slower" if you're in a wheelchair.The beeper frequency maybe has to do with cost as well, as it's cheap and easy to grab an off the shelf part that works for most people. And the option to change frequency or volume shouldn't be a feature, it should be standard really. I mean which TV doesn't have audio settings.If there were light-up probes (the finger guard at the end of a probe could light up well) they better be very bright so that they're visible in bright factories as well as outside.Maybe we should discuss these and other options in another thread, as I'd like to collect more suggestions for meters that already exist. I'm sure there's more than just the Keysight U1232A and the Brymen BM235...

author: Fungus
author_rank: Super Contributor
timestamp: February 21, 2020, 04:37:54 pm
content: Quote from: cyb3rphil on February 21, 2020, 02:59:29 pmThe problem is that they have to be sealed inside a thick plastic case for CAT safety reasons, often with a rubber shoe around the outside as well.Maybe a solution would be to drill some discrete little holes near the buzzer to let the sound out.

author: AVGresponding
author_rank: Super Contributor
timestamp: February 21, 2020, 05:38:16 pm
content: Quote from: Fungus on February 21, 2020, 04:37:54 pmUnfortunately this also lets the magic smoke out in an uncontrolled manner and removes any chance of worthwhile CAT ratings.One solution might be to hard bond the piezo sounder to the casing, but as ever, this would increase the manufacturing cost and therefore is unlikely to happen.

author: liketolurk
author_rank: Newbie
timestamp: February 21, 2020, 07:42:46 pm
content: So this thread lured me out of lurkingwould it not be possible to create a device that is triggered by the continuity beeper (audio) and vibrates accordingly, there would be some margin for error in an industrial environment but it's not voice recognition and the distances can be reasonably short?Also there must be a ton of industrial electricians with damaged hearing and fluke already have vibrating two point testers as mentioned earlier in this thread, it might not be a bad idea to poke some sales reps about it :-pAnd thinking on it further it might actually be good value to add blue-tooth audio support for compatibility with some 3m (or other) products intended to prevent loss of hearing in noisy environments, that might also solve the problem of several people working in close proximity.

author: cyb3rphil
author_rank: Contributor
timestamp: February 23, 2020, 10:25:34 am
content: For continuity you could attach it to the display with a suction cup if the display is kept clean and scratch-free. Then press a button while the beeper sounds to make the thing "learn" the sound of the beeper so it reacts only when it sounds, and because it's fixed to the meter, the volume will always be more or less the same. The output could then be a very bright LED or an extra loud beeper. However this obstructs the display and adds the inconvenience of attaching a separate device before testing.

author: cyb3rphil
author_rank: Contributor
timestamp: February 23, 2020, 09:45:16 pm
content: Aren't there any other visually indicating continuity testers out there?

author: vk6zgo
author_rank: Super Contributor
timestamp: February 24, 2020, 12:35:33 am
content: Quote from: cyb3rphil on February 23, 2020, 09:45:16 pmYes, it's called the Ohm's range on a multimeter!Back in the day, with analog multimeters, we measured continuity by using Ohms range & looking at the needle.The advantage of this, (or the equivalent range on a DMM), is that you read the actual resistance of a connection.Many "continuity" tests on DMMs will quite happily "beep" when the resistance is as high as 30 Ohms, which may, in service, cause a fault condition.OK, they have their place, but it is more in trying to sort out connections on an unknown cable or tagblock.This used to be done with a battery & buzzer.The buzzer drew a fair amount of current, so if there was some tens of Ohms resistance in line, it would make a difference to the sound level/ frequency of th buzzer.People have become so enamoured of the "continuity" function, that they use it when testing inside devices, freaking older Techs out.

author: cyb3rphil
author_rank: Contributor
timestamp: February 24, 2020, 11:47:09 am
content: Right, but the continuity tester that beeps is designed to be more convenient as it speeds up testing. If you touch the probe to a pin and instantly hear a beep, you know you got a somewhat decent connection. Of course I could look at the display, but then I'd have to hold the probes still until the reading stabilizes, then make sense of the numbers displayed etc. The beeper removes that messing around and gives a clear yes or no answer.Also, as I have stated before, there are situations in which you can't place the meter to conveniently look directly at the display.That said, if the quality of a connection is important (rather than finding out where the wire that's buried deep in the wire guide goes) you're indeed better off using the Ohm's range.Oh, and also. Most DMM continuity modes output very little current, reducing chances of damaging equipment if the current flows through it. And they have input protection, so they won't explode or anything if you accidentally connect it to some high voltage. But yes, in many cases, a battery and buzzer (or in my case a light) can be an effective solution as well.

author: kripton2035
author_rank: Super Contributor
timestamp: February 24, 2020, 12:46:24 pm
content: Quote from: cyb3rphil on February 23, 2020, 09:45:16 pmthere are some here :http://kripton2035.free.fr/continuity-repos.html

author: cyb3rphil
author_rank: Contributor
timestamp: February 27, 2020, 11:51:16 am
content: Quote from: kripton2035 on February 24, 2020, 12:46:24 pmThanks for the link, very interesting stuff. These aren't commercially available multimeters though.So my boss had the Brymen BM235 ordered and it arrived today. I guess the Keysight was too expensive, which I can understand. I gave it a quick test and the LCD backlight is actually flashing instead of lighting up. It's reasonably bright, maybe a bit brighter than a Fluke 117, but I have to put both meters next to each other for a better comparison. The beeper is MUCH quieter than the Benning MM 5-2, which is about as loud as the 117. I can barely hear it even when putting it right next to my ear. However, the blinking LCD light is much more noticeable than the tiny NCV LED, so that's a big plus for me.I will post a more detailed review of it after I've used it for a while.Please keep posting suggestions for other multimeters, I'm still interested in knowing what other stuff is out there...

author: Fungus
author_rank: Super Contributor
timestamp: February 28, 2020, 02:51:03 pm
content: Quote from: vk6zgo on February 24, 2020, 12:35:33 amBack in the day you didn't have more than about three wires to choose from. No 200-pin packages to zip along the sides of.

author: cyb3rphil
author_rank: Contributor
timestamp: May 06, 2020, 05:46:59 pm
content: Hi all,so I have been using the Brymen BM235 for a while now, mostly for continuity checks but I also took some voltage measurements.Overall it's a good meter, as already mentioned in continuity mode it beeps relatively quiet (quieter than the Flukes I've tested, but louder than my Uni-T UT61D). To me at my workplace, the beeper is barely audible, but it's not really needed anyway. The display lights up with no noticeable delay (it turns off if the backlight is already lit) and flashes about 1 time a second. However that doesn't matter, as long as I can notice the display doingsomethingI know there's continuity. I always touch the probes together to check if it's working properly and to make sure I can see the display while not actually looking at it.The backlight is also relatively bright (could be brighter, say about as bright as a Fluke 115). If you don't shine a desk lamp directly at it you will see it lighting up.The meter is well equipped (it has everything a good meter needs to have), and it's nice that it remembers which mode selection it was in last time the rotary switch was in that position. So if you don't do resistance measurements too often but instead continuity, it stays in continuity mode when you switch it to the ohms range, until you press the mode button to switch it back. It does that for the voltage and current (switching between DC, AC and a AC with low pass filter) and diode/capacitor modes too. I find this to be a bit inconvenient especially in the voltage mode, because you have to remember the last setting yourself or look at the display to make sure the correct mode (AC or DC) is selected. You can't just memorize "turn to V setting then press mode button for AC volts) or something. If you're almost always using one setting only then it'd make sense.Another thing I find inconvenient is the LoZ setting, which is to the left of the OFF setting. You can't turn the switch all the way to the left until it stops to turn it off.Other than that and the quiet buzzer, I really like this meter. I've 3D printed a better kickstand (the original one is really badly designed as it doesn't really support the meter when you're pushing the buttons, it just flops back) and a magnet holder so I can stick it to a metal surface like the Benning I had previously.I hope someone else finds this info useful - there's really not a lot of (fast) visual indicating continuity testers out there...