Multimeters are one of the key tools in a hardware hacker’s bench. For 90% of us, the meter leads are perfect for making measurements and looking over at the results. Sometimes you need a bit more distance though, and for that, [Ken Kaarvik] has created the Multimeter remote display. Remote displays are pretty handy when you want to measure something several feet away from your bench. They’re also great if you need to check something in an enclosed space, like a server rack or a refrigerator. Fluke actually sells multimeters with wireless displays, such as their model 233.
The key to this project is the FS9721 LP3 chip by Fortune Semiconductor. (PDF link) The FS9721 is essentially a system on chip (SOC) for multimeters. It contains a digital to analog to digital converter, an LCD driver, and a microcontroller. It also can send data out over a 2400 baud serial link. Two of [Ken’s] multimeters, the Digitek DT-4000ZC and a Fluke 17B, both have this chip. The Digitek has a 1/8″ plug for connecting to the outside world, while the Fluke requires some simple hardware mods to enable data output.
Since this was his entry for the Trinket EDC contest, [Ken] connected the serial output of the FS9721 to an Adafruit Pro Trinket. The Trinket formats the data and sends it to an nRF24L01+ 2.4GHz radio module. The receiving end has an identical radio, and another Pro Trinket. [Ken] actually built two wireless displays. One is a dual-boot Game Boy advance which has a really slick background on the color display. The other receiver utilizes a 128×64 OLED. The trinket, nRF24L01+ and display all fit neatly inside an Altoids tin.
Click past the break to see both wireless remote displays in action!
Really cool!
Something like this could probably easy be done with the UNI-T UT61E multimeter, as it has a optical to serial output to connect the meter to the PC (read only, you can’t control the meter from the PC). See here for more information: http://lygte-info.dk/review/Review%20UNI-T%20UT61E%20UK.html
the Most UNI-T Multimeter are equiped with this.
I was building an BLE/Bluetoth Modul with CR20XX and HM-11/HM-13
for this.
But there are Modules to http://www.uni-trend.com/en/product/2014_0626_536.html
See this: https://moosh.im/ – meter that uses your smartphone as the display, via Bluetooth low energy.
This got me to thinking about the bluetooth meters that have been mentioned here so I did a quick search and found this meter the TekPower TP9605BT Multimeter. It is only sold by one source but cost only $79.00 usd with shipping. Here are the specs; Full Function 6000 Counts True RMS Multimeter with Intelligent Connections, Bluetooth Cellphone Connected Multimeter ( Android Only Now), USB connected multimeter, Comes with K-Type Thermo sensor and Optical USB Cable, Free APP software and USB Data logger software. It seems to be so new I am unable to find any reviews. I did purchase one to play with and see how “hackable” it might be.
I also wonder how much the vendor provided app sucks (or doesn’t).
“They’re also great if you need to check something in an enclosed space, like a server rack or a refrigerator.”
In a server rack, maybe, but not for sure. It depends of the rack. Inside a fridge, definitely not, because the fridge case is metallic, and it will act as a Faraday cage.
Only if you lock yourself inside of it!
Like Indiana Jones?
You’d damn well better hope that the fridge you select to shield you from a nuclear blast is indeed a Faraday cage.
Yes, but the door gaskets are rubber, so I suspect plenty of signal would make it out.