I found this interesting activity which involves students decoding binary numbers. The activity involves students drawing a picture on pixels, coding their picture and decoding another studnets picture.

1. Studnets are to draw a picture using the pixels only using black or white

2. The student then code the picture with white square representing 0 and black squares representing If the paper is 8X8 each line should have 8 numbers.

3. Studnets  are now the decoders so studnets have to  swap their code (hiding the picture) with someone else in the class and have to try to put the picture back together using the code.

Here is the link

https://www.digitaltechnologieshub.edu.au/teachers/scope-and-sequence/5-6/data-representations/representing-images-using-binary

Here is an example of a completed worksheet

https://www.digitaltechnologieshub.edu.au/docs/default-source/Lesson-Ideas/5-6/using-binary-to-create-on-off-pictures/pixel-binary-template—completed-example.pdf