How reliable is Dupont wire???

lingking

How reliable is Dupont wire??? [Copy link]

 

Some time ago, I used my STM32 development board to do an experiment to read BMP image files and display them on LCD. The effect was pretty good. Then I bought an OV7725 camera module and tried to adjust the camera. After transplanting the program given by the seller, the image data on the LCD was always abnormal. When I hold something close to the camera, there will be a corresponding color on the LCD, but the picture on the LCD is tilted and distorted to the point where the outline cannot be seen at all, and the image is still scrolling to one side. As shown in the figure;;;; Originally, I thought this phenomenon was caused by the LCD's inability to keep up with the refresh speed, but I immediately went to consult the seller, and they also tested it on the same model of LCD and took a video to show me that it was completely normal. The difference is that the development boards are different and the connection methods of the modules are different. They plug the camera module directly into their development boards, while I use Dupont cables to connect to the development board (because my board does not have the corresponding socket). From now on, it should be a problem with the Dupont cables. I don’t know if the cables are in poor contact, interfering with each other, or the signal itself is distorted. I don’t have an oscilloscope and can’t see the actual communication speed. I can only guess. Alas...


         

dcexpert

Nowadays, DuPont wires are mass-produced in factories and crimped together. The wires are thinner and occasionally have poor contact. They are suitable for general experiments, but not for large currents and high-frequency signals.

star_66666

It is enough for testing, but not for the product.

topwon

Not only the contact problem should be considered, but also the interference and impedance control problem should be even greater. The frequency of the data line and clock line of the camera to transmit the image is relatively high, at least use a flat cable to connect (if the module uses differential signals, also consider using twisted pair cables), and arrange ground wires on both sides of the clock line. It is normal for problems to occur with the messy wiring like the one in the picture. It is recommended to make an adapter board and finally connect the module with FFC or other flat cables.

lingking

topwon posted on 2019-5-6 09:52 Not only the contact problem should be considered, but also the interference and impedance control problems should be even greater. The frequency of the data line and clock line of the camera to transmit the image is relatively high, at least...

Suddenly I thought of drawing a "U"-shaped adapter board, and then covering it, leaving a camera interface on the adapter board to plug the module in. This should be the last resort: Sad:

strong161

Buy good quality thread and press it yourself!

lingking

strong161 posted on 2019-5-6 11:52 Buy high-quality wire and press it yourself!

Forget it, I'll just draw a board to transfer it myself

数码小叶

Dupont cables are really unreliable. They can seriously mess up SD reading and writing. Moreover, the quality of Dupont cables sold on Taobao varies a lot.

lingking

Digital Leaf published on 2019-5-6 13:08 Dupont cables are really unreliable. SD card reading and writing are seriously screwed by them. Moreover, the quality gap of Dupont cables on Taobao is really...

The reading and writing speed of SD cards seems to be quite high. The signal transmission of Dupont cables may not be good enough.

数码小叶

lingking posted on 2019-5-6 13:10 The SD card read and write speed seems to be quite high, the Dupont line may not be able to transmit the signal

Yes, I took the step of reducing the frequency after I found the problem

topwon

For high-speed signals, DuPont lines have the following problems: 1. There is no reliable reference ground as an impedance control method and return path; 2. The wiring positions are messy and difficult to fix; 3. The contacts are loose and prone to poor contact; so it is easy to cause signal waveform distortion and serious crosstalk problems.

29447945

Tie the wires together. I have also adjusted it. Separate the wires and tie them together.

lingking

29447945 posted on 2019-5-6 13:23 Tie the wires together. I have also adjusted it. Separate the wires and tie them together.

I have tried it, but it doesn't work.

lingking

Digital Leaf published on 2019-5-6 13:11 Yes, we took the frequency reduction operation after discovering the problem

Did it work later?

lingking

topwon posted on 2019-5-6 13:19 For high-speed signals, Dupont lines have 1. No reliable reference ground as a means of impedance control and return path; 2. The routing position is messy and difficult to fix; 3. The touch...

I plan to draw an adapter board

数码小叶

lingking posted on 2019-5-6 14:41 Did it work later?

It was ok after the frequency was reduced. After the PCB was soldered, it could work at the normal frequency.

zhuyebb

Buy high quality wire and press it yourself

lingking

zhuyebb posted on 2019-5-6 19:31 Buy high-quality wires and press them yourself

Don't bother with that. Just draw an adapter board and send it out for proofing. You will know it when you plug it in.

qwqwqw2088

DuPont wires are commonly used in testing, but few people use them because they are convenient and quick to connect products. After all, the connection is not firm.

lingking

qwqwqw2088 posted on 2019-5-6 21:00 Dupont wires are commonly used for testing, but few people use them because they are convenient and quick to connect products. After all, the connection is not firm

The problem is probably clear. It is a problem with the hardware or PCB design. I bought a cheap development board and got ripped off