We’ve seen designs like this become more popular lately as many folks have phones on hand, which can act as a display (the display/UI is one of the more difficult and expensive elements of portable test equipment). When this one popped up on https://www.digikey.com/new we thought it would be worth checking out as it does a good job of matching enough desired specifications to be useful to a Maker or engineer.
We like the mechanical design – it has got a cute retractable cable kit that you can pull out for use. The design of the probes is such that you can plug in optional and included micro-grabbers if desired, but the tips can be used as is. (We’ll note that the micro grabbers don’t fit into the body or anything so they need to be carried separately). While it’s a tad large for a keychain, it isn’t an outlandish size – it definitely could go into a purse or pocket without snagging. There’s also a zipper pouch for those who like to keep their tools in a home.
To work with any phone, it uses BLE for data transport. Unlikely many products we see, this doesn’t use a rechargeable battery. Instead, the battery is an every day CR2032 which you can get replacements for at any hardware or corner shop. There’s pros and cons to going with a primary cell, but we think this was probably a good choice as long as the battery level is well communicated to users.
The processor inside is a Silabs EFR32BR13 wireless microcontroller and a little bit of circuitry. Connecting is easy, after removing the battery tab, download and open the app, it will pair immediately – this went very smoothly. Then from the main screen you can select various functions. Most functions acted just the way you expect: continuity test, DC voltage measurement, temperature and resistance. There is a current measurement capability, which also means there’s a fuse. You do get a spare fuse, and as most multimeters go, its something you’ll probably mess up once by accidentally measuring in parallel. Thankfully the app warms you before going into current measurement mode.
There’s only one thing that folks should be aware of: there is an ‘oscilloscope’ mode but it really is more of a ‘data capture’ mode – the BLE link isn’t fast enough to stream data, even triggered-signal data. Arguably, it’s hard to do this reliably over BLE, but I think it is possible to have some data rate streamed, even if just to make it easier to verify that the right spot is probed – and it would be a really awesome feature. I think BLE 5 with large, non-acknowledged packets could do it. But perhaps it wouldn’t work reliably on every model of phone. Hopefully next revision could do it since it would be such a killer feature!
For something so small, it really does pack a good amount of capability, and while it would not replace your desktop scope or multimeter, it is a great addition to a dev kit. I could have really used something like this when traveling or at events! We picked up the transparent one because we are suckers for clear plastic, but there are a few different colors of the Pokit All-in-One Meter, all of which are available in stock at Digi-Key right now for immediate shipment. Order today and you’ll be toting this lil keychain toolkit with you tomorrow afternoon!
See on DigiKey.com at https://www.digikey.com/short/3pvz50db
See the Pokit video below.