Deutsche Version
Deutsche Version

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Projector 'Joy' from GammaBai

The gadget in moving pictures and with audio

You can buy the GammaBai Joy on Amazon.
By purchasing via the specified affiliate link, you support "How Open Is This Gadget?" without any additional costs for you - thanks!

How Open Is This Gadget?

Category Remark Info
Firmware Firmware is closed source.
Hardware All parts are bolted, components can be easily replaced.
Website The manufacturer's website offers up-to-date information about the devices, emails are answered.
No download section for Firmware Updates.

About the gadget

Figure 1:
The "Joy" is a cheap entry-level projector, but the electronics offer a wide range of functions. With a weight of only 1.4kg and the dimensions 145x175x175mm, the "Joy" is anything but heavy and quite compact, so that the device can easily be carried around. For that, a strap of synthetic leather is attached on top of the projector.
The great advantage of these devices is that they convert any white wall into a screen and the size of the projection surface can be freely selected within wide limits.

Technische Daten

Category Value Remarks
Resolution 1280x720 Ratio: 16:9
Dimensions 145x175x175mm  
Weight 1.4kg  
Minimal focal length 125cm Results in a screen diagonal of 95cm
Energy consumption 48W Case temperature approximatels 35°C, 50°C at the cooling air outlet.

Package contents

Figure 2:
Included in the shipping box are a power cord, an HDMI and an AV cable as well as a remote control.


Figure 3:
A matrix of 11x6 corresponding to 66 LEDs serves as the light source. These LEDs consume the largest part of the electrical input power and must therefore be actively cooled in order to remove the dissipated power. The fan used for this is temperature-controlled, but somehow always turned on which can be heard.
The image generated by a 1280x720 pixel LCD and two Fresnel lenses, is directed to the front lens via a mirror.

Photos test patterns

Figure 4:
Uniform illumination.
Details on the test procedure.

Figure 5:
Test pattern.
Details on the test procedure.

Figure 6:
Details on the test procedure.

My conclusion

The "Joy" from GammaBai is a low-cost projector for your entry into the world of "big pictures" or as a second device on the go. You shouldn't expect perfection at the asking price, but you definitely get a device that at least throws good projections onto any white wall, provided the ambient light is rather low. When it comes to electronics and firmware, the "Joy" is very flexible. Data can be transmitted both wirelessly and via USB.
The big downside: the firmware is closed source (which is unfortunately true for the competitors as well).
...and because we're talking about a cheap device with a plastic case that gets warm during use: The first video evening should be held in a well-ventilated room. After a few hours of operation, the vapors will dissipate and the cinema fun will increase.

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