Review on ACECAR Universal Dual System 3.5 Inches HUD - Head Up Display for Car with OBD2 GPS Interface, Speedometer, Engine RPM, OverSpeed Warning, Mileage Measurement, Water Temperature - Suitable for All Vehicles by Ines Jones

Ignore the 1 and 2 star reviews. All the issues raised in these reviews can be solved if they read the manual and set it up properly. Of course, the instructions are written in broken English or with the help of a Google translator, but you don't need to be a genius to understand them. The manufacturer is so desperate for people to read the manual that they put 2 copies in the box I received. I bought it for $23 when it was on flash sale. To solve two of the most common problems, OBD speed is NOT accurate out of the box. To calibrate it, you need to drive at highway speed and notice how much the displayed speed differs from your speedometer. Once you've parked safely, hold down the scroll button until you see '1', which means option 1 of the settings menu. Press the button again and you can calibrate the speed. Roughly speaking if the HUD shows 65 mph while driving at 60 you should set it to 107 (default) - 5 = 102. The calibration value here is not equal to 1:1 of the displayed mph offset, it takes some trial and error to enter it. I ended up setting it to 103 on my Honda and Toyota. By default, the HUD will alert you when you exceed 5000 rpm or 150 km/h. I have another HUD that allows you to turn off the alarm entirely, but I haven't figured out how to do that with this one. If anyone knows please let me know. I just set menu item 2 to 75 (7500 rpm) and option 4 to 199 (123 mph). Unless you live in Germany, you will probably never activate the alarm after setting options 2 and 4 to the maximum. I left all other menu items as default. If your vehicle has an automatic engine start and stop, you can increase the delayed shutdown timer (menu option 10) from the default 20 seconds to prevent the HUD from going black when stuck at a long red light. Compare with my other HUD (https://www.amazon.com/gp/product/B01NADDHED/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1), auto-brightness works much better on this HUD. The other HUD has a poor light sensor and the display is too dim to read in the late afternoon when the sun is slanting on it. I haven't encountered this problem with this HUD yet. The ambient light sensor seems to be quite sensitive and reacts to changes in the ambient light. I also like the simple layout of this HUD. The rev band is accurate and responsive. I turned off the white, blue, and red lights to keep the windshield from lighting up like a Christmas tree when driving. With all accessories, the OBD HUD consumes power all the time, even when the car is off. When the display is switched off, the HUD goes into sleep mode, which according to the instructions draws 20 mA. With a fully charged, healthy battery, it's safe to leave it plugged in for at least 2-3 weeks without completely draining the battery, but the manual recommends unplugging it if you're not going to ride for more than an hour. a week or so.