Overview

• This simple and cheap device has many uses, but it’s mainly intended to replace multiple panel meters.
• It can also be used as a small additional text screen for PC, Raspberry Pi or any other computer with USB.
• Whilst working on the high-current linear power supply design it became clear that we needed a way to show several different voltage and current readings, along with heatsink temperature, and it just didn’t make sense to use several panel meters for that job.
• It’s difficult enough to cut a single neat rectangle in the front panel of the instrument case to fit one screen, let alone three or even five.
• And there would be a lot of extra wiring if we used separate panel meters, plus increased current draw and it could end up pretty expensive.
• This one low-cost device using a micro, an LCD screen and not much else makes the whole thing so much easier.
• There are two ways to use this board. In the Bench Supply, we’re feeding in five analog voltages with a common ground. These voltages are a fraction of the actual measured voltages (ie, the outputs of voltage dividers).
• The onboard micro samples these voltages and converts the values back to the original scales, then displays on them on the screen.
• In the case of the fifth input, which is used for temperature sensing via an NTC thermistor, it also performs the required calculations to deal with the non-linear behaviour of the NTC.
• In the other mode, the micro detects when it is plugged into a USB interface and then behaves differently.
• You send it text over a virtual serial link, which is shown on the display.
• So you can easily show whatever you want on the 16x2 or larger 20x4 character backlit LCD screen.

Important Note For Kit Buyers:

• This product is supplied in component form and requires soldering, drilling, and assembly.
• We recommend users are familiar with at least basic electronic principles and have the ability to solder.

Features

• Shows two voltages, two currents and one temperature reading on a 16x2 LCD
• In alternative USB mode, ASCII text from virtual serial port is written directly to 20x4 LCD
• Panel meter input range: 5 x 0-4.096V
• Panel meter scaling: 2 x 0-4.096V -> 0-60V, 2 x 0-4.096V -> 0-9A, 1 x 0-3V -> 0-100°C
• Panel meter resolution: 58.6mV for voltages, 8.79mA for currents
• Panel meter update rate: 5Hz

warranty

• We offer 12 months warranty on this product from its date of purchase