# 555 Timer & Oscillators Pro vs AVR Projects

The clearest difference is price: AVR Projects at Free against 555 Timer & Oscillators Pro's $4.99. AVR Projects also leads on update cadence (daily vs every 2 months). 555 Timer & Oscillators Pro's advantage is in-app purchases (none vs 10). On ads, device support and iOS requirement there is nothing between them.

AVR Projects is free to download; 555 Timer & Oscillators Pro costs $4.99 up front. AVR Projects sells 10 one-off in-app purchases. 555 Timer & Oscillators Pro asks for nothing beyond the download.

555 Timer & Oscillators Pro ships an update every 2 months, AVR Projects daily. Both last shipped on October 25, 2026.

## The numbers

| Metric | 555 Timer & Oscillators Pro | AVR Projects |
| --- | --- | --- |
| Price | $4.99 | **Free** |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 2 months | **Daily** |
| Size | 22 MB | 20 MB |
| Requires iOS | 17.0 | 17.0 |
| Devices | **iPhone, iPad, Mac** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [ALG Software Lab](https://appshunter.io/developer/1650561236) | [Zaw Win Myat](https://appshunter.io/developer/1800881321) |

## What reviewers say

### 555 Timer & Oscillators Pro

[App page](https://appshunter.io/ios/app/555-timer-and-oscillators-pro/id6504415162)

**Features:** Vision Pro support

**In-app purchases:** none


### AVR Projects

[App page](https://appshunter.io/ios/app/avr-projects/id6745124011)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (10)**

| Purchase | Price | Billing |
| --- | --- | --- |
| R2R Ladder DAC | $0.99 | one-time |
| Sawtooth Waveform | $0.99 | one-time |
| Triangular Waveform | $0.99 | one-time |
| Sine Waveform | $0.99 | one-time |
| Ammeter AVR | $0.99 | one-time |
| 4x3 Matrix Keypad | $0.99 | one-time |
| Ohm Meter AVR | $0.99 | one-time |
| Voltmeter AVR | $0.99 | one-time |
| TM1637 Interfacing with AVR | $0.99 | one-time |
| Graphic LCD Interfacing | $0.99 | one-time |


## Frequently asked questions

### Is 555 Timer & Oscillators Pro free?

555 Timer & Oscillators Pro costs $4.99, with no in-app purchases.

### Is AVR Projects free?

AVR Projects is free to download, with in-app purchases available.

### Do 555 Timer & Oscillators Pro or AVR Projects have ads?

Neither 555 Timer & Oscillators Pro nor AVR Projects shows ads.

### Which is updated more often, 555 Timer & Oscillators Pro or AVR Projects?

555 Timer & Oscillators Pro ships an update every 2 months, and AVR Projects daily. Most recently, 555 Timer & Oscillators Pro was updated on October 25, 2026 and AVR Projects on October 25, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*