What hardware requirements does a SPV client have?
Bandwidth - You need to receive an 80-byte header about every 10 minutes. In addition, if you want to spend, you will get SPV proofs that range about 500-1000 bytes per utxo. In other words, the bandwidth requirements are really tiny.

Storage - Each block header is 80 bytes, as of this writing, there are less than 430,000 blocks, so 80 * 430,000 = 35.4 MB. 100 MB should last you another 15 years.

RAM - The main usage of RAM is to do SHA256 and ECC signing/verification operations. A minimal CPU with not much RAM (512 MB) can do both without a problem.