4 Line LCD Build - BOM and any instructions.

My search fu may well be weak - but I cant' find information on a 4 line LCD build. The only thing I found was from 2015 and no P/N listed.

I am building a successor to my Heatermeter Buddy build and want to go with a 4 line display.

I don't need anything fancy - a 4 line Part # comparable to the stock 2 line is fine - and something preferably pin compatible.

I'd appreciate pointers to builds, BOMs, and such that I missed.

Once I get going I'll post another build link as this will be outdoor and fully waterproof and intended to be left on top of the smoker. Related I just gutted a donor MES 30 to 1200 watts, 350F cutout, HM compatible accurate probes, and no controller. This will be the host for the new build but I'll post information on both.

Appreciate some help if not clue bat on the 4 line LCD options or P/N to order.

Bryan Mayland

TVWBB Hall of Fame
I don't think we ever used anything from Mouser so there wasn't any part number for it. I bought like 5x new old stock from eBay back when the 4-line mode was suggested. The ones I have, Varitronix MDL-20464B-LV-GLED4, are 20x4 but note that even in 4-line mode, HeaterMeter still only fills 16 characters wide. I don't think you can use 16x4 character displays though, because the RAM layout might set row two at RAM location 16 instead of 20, which is where we put it. I do know some 16x4 LCDs work, but I remember someone posting a 16x4 display where row 2 was shifted right by 4 characters, then row 3 was off by 8, and row 4 was shifted by 12. You can probably find something by searching eBay for 2004 or 20x4 LCD. You want one with the cheaper HD44780 parallel interface, NOT "IIC/I2C/TWI/SPI".

I do not know which model Tom used to base the 4-line 4.2 HeaterMeter case on, and there's no case design for a 4-line 4.3 HeaterMeter.

To connect the LCD, you'll need to run wires from the LCD footprint on the HeaterMeter to the LCD pins, because not even NewHaven Display makes a 20x4 with the header along the bottom.
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Thanks Bryan for the part number. I just found 4, "pre-owned" but looking good, on ePray. He's asking $33 and I've offered $15; might consider going to $20. Not a big deal otherwise as It's mostly wifi access.

For this 2nd build (thanks for prompt shipping on the kit!) I'll use another Pi Zero W or a 3A+.

The case isn't an issue as It's going totally custom.

But my goal is to have a leave-out-uncovered controller as my Heatermeter + Heatermeter Buddy is a setup/take down "semi-chore".
To address that I've
  • Replaced the MES internal meat probe with a 72/73 (I strongly prefer Thermoworks - but a 6' cable allows meat / probe length to the side of the smoker without pulling out of meat).
  • Co-ran a new thermocouple pit probe - for bottom rack clip - orphaning the original pit probe.
  • So that addresses the probe related setup/tear down.
The Weather issue intention is
  • Carlon 4x4 or 6x6 abs box
  • Membrane switches (Adafruit has a nice 1x4)
  • IP67 toggle switch boots
  • Liquid Tite fittings for the extension cord stubs (no IEC)
  • Something - maybe water-tight phone case? with closed cell foam "seal" on the bottom.
  • LCD cutout, membrane switch cutout, and backside SSR heat sink, RTV sealed.
I'm hoping that work. And that the vendor with those 4 line displays accepts my offer.

Thanks! Mike


New member
I have a 4 line since I purchased and built my HM back in '17. Still going strong!

The LCD was a mere $7.56 Australian including shipping back then, the ebay description was: "IIC/I2C/TWI Serial LCD 2004 20x4 Display Shield Blue Backlight for Arduino New T"

I had to solder in a ribbon cable to the parallel pins as Bryan mentions in his reply, a header with pins will not work as there are some cross-overs, quite straight forward as the pins are labeled on the silkscreen of the LCD and easy to match with the details available with the HM schematics. The little serial daughter board is not used and just taken off.

Here an older photo of my HM/Damper with 4-line LCD & built-in fan combo. I have since upgraded the pushbuttons to these below.


I have an older HM 4 line and decided to build a new on on the 4.3 platform. I'm good on the electronics bus will need to modify the case. I'm able to do what I need in F360 but am lost with OpenSCAD. Can anyone help with adding a 4 line cutout option? Or anyone help getting it to a format F360 can handle? Best i can do is export as an STL and import as a mech body in F360 but that is a royal pain. Any help would be appreciated.