TABLE OF CONTENTS
- DAKOS and HDMI:
- HDMI connections of the CPUs Mini, v3, v4, and v5:
- Frequently Asked Questions:
- Can you see two different Screens or photos when using the Dual output on the CPU v4 or v5?
- Does the Secondary HDMI output support audio?
- Can DAKboard CPUs be converted to work on other input types?
- What does it mean when the TV Shows No HDMI Signal?
- How long of an HDMI Cable will a DAKboard CPU support?
DAKOS devices, whether purchased from our Shop, one of our Resellers, or done as a DIY project all use HDMI as their method to connect to the display. This article intends to cover the various HDMI connections you will find on Orange Pi and Raspberry Pi computers we use, or that you can buy, and how they play an integral part of your complete Display package.
DAKOS and HDMI:
The DAKOS not only uses the capabilities of HDMI to send and receive Audio and Video, but it also uses these lines of communication to gather information on your Monitor/TV's make and model. Furthermore, we utilize the CEC capabilities of most modern TVs and Monitors to allow you to turn on and off your Monitor/TV using the DAKBoard device's built-in On/Off (Sleep) Schedule.
Because we use advanced features such as CEC, when a DAKOS device first boots up, it reaches out to the connected Monitor/TV to confirm it is using the HDMI connection and waits for a response. Sometimes it fails to get this response and reacts by rebooting itself to try and establish communication. If your DAKOS device is boot looping, only going to the DAKboard loading page, or a rainbow-colored screen repeatedly, this means that your DAKboard is not getting the response from your Monitor/TV.
This can be a sign that either your HDMI Cable is bad or your connection to the CPU and Monitor/TV is loose. If the cable is bad it will need to be replaced if the connection is loose, you can correct this by simply unplugging the power to your DAKboard CPU, unplugging both the HDMI connection on the CPU and the Monitor/TV, then plugging the HDMI cable back in making sure the connection is sound on both ends. Then simply plug the power back in, and your device will start up.
HDMI connections of the CPUs Mini, v3, v4, and v5:
The latest version of the CPU v3 is powered by the Orange Pi 3 LTS. This model has been discontinued due to the lack of support from Orange Pi and the Operating Systems they use. The current models are the CPU Mini, powered by the Raspberry Pi Zero 2W, the CPU v4 is powered by the Raspberry Pi 4B, and the CPU v5 is powered by the Raspberry Pi 5. As seen below, the v3 has a single standard HDMI output:
The CPU Mini has a single Mini HDMI output:
While the v4 and v5 support Dual Micro HDMI outputs.
Though the v4 and v5 have two HDMI out, they do not function independently. This means that the Secondary HDMI output, the one furthest from the power supply, is just a mirrored copy of the Primary HDMI output. So you can hook the CPU v4 or v5 to multiple monitors, but it will show the same Screen on both monitors.
Below is a matrix of what is supported by these HDMI Outputs:
| Device | Supported Output | Video | Audio | CEC | Individual Screen | Resolutions |
| CPU v3 | HDMI | Yes | Yes | Yes | Yes | 2k UW, 4k, 1080p, 720p |
| CPU Mini | Mini HDMI | Yes | Yes | Yes | Yes | 1080p, 720p |
| CPU v4 | Primary Micro HDMI | Yes | Yes | Yes | Yes | 2k & HD UW, 4k, 1080p, 720p |
| CPU v4 | Secondary Micro HDMI | Yes | Yes | Yes | No | 2k & HD UW, 4k, 1080p, 720p |
| CPU v5 | Primary Micro HDMI | Yes | Yes | Yes | Yes | 2k & HD UW, 4k, 1080p, 720p |
| CPU v5 | Secondary Micro HDMI | Yes | Yes | Yes | No | 2k & HD UW, 4k, 1080p, 720p |
NOTE: As of version 4.01 and above, the DAKboard CPU v4 and v5 will support audio through both the Primary and Secondary HDMI outputs as well as through the auxiliary headphone output. If you are running an older version, 3.54 and below, you will need to upgrade to get these added features. You can upgrade to the latest version of the OS by following the steps in our article, Raspberry Pi - Download and Install the DAKOS, or Orange Pi - Download and Install DAKOS.
Frequently Asked Questions:
Can you see two different Screens or photos when using the Dual output on the CPU v4 or v5?
No. This is because the secondary output mirrors the primary output. Both will show the same screen at the same time.
Does the Secondary HDMI output support audio?
For versions 4.02 and above, the Secondary HDMI output now supports Audio. For version 3.54 and below, this was not supported.
Can DAKboard CPUs be converted to work on other input types?
No. The DAKboard CPU requires the use of HDMI signals to function properly. Converting the HDMI signal to any other input type (like DVI, Display Port, VGA, or RCA inputs) will cause the CPU to fail to function or behave in unpredictable ways. You should only use monitors/TVs with HDMI inputs and should use monitors/TVs that support CEC (Consumer Electronic Controls) to be able to take advantage of all the DAKboards OS functionality.
What does it mean when the TV Shows No HDMI Signal?
This message would be coming from your TV or Monitor, not from the DAKOS. This could be caused if the wrong HDMI input is selected on your TV or Monitor, or the HDMI signal is not being sent or received. Double check you have the correct input selected on your TV or Monitor, make sure the CPU's power is on, and if you are still not seeing the image, try unplugging and plugging the HDMI cable back in on both the CPU and TV, or replacing the HDMI cable.
How long of an HDMI Cable will a DAKboard CPU support?
The DAKboard CPUs are all mini computers, because of this they do not have a lot of power to spare for long HDMI cable runs. In testing, we found that about 10 ft is the longest you can run an HDMI cable without assistance from our CPUs. We recommend runs smaller than this to prevent signal loss.
Helpful Articles:
Having trouble? See if these articles help.